Menai Bay Conservation Area Guide Book

Transcription

1 HERE ARE SOME WAYS THAT YOU CAN TAKE A PART IN PROVIDING A FUTURE FOR CORAL REEFS Respect the life you have come to see and remember that it is you who are a visitor in their world. N Never capture, feed, handle or harass any marine life. Never touch, stand on or collect coral. Take care to control how you are swimming so that you do not break or knock coral. Never purchase coral reef souvenirs. Tell other people not to purchase them. Do not order turtle or shark meat in restaurants or any food made from endangered wildlife. If you are unsure then choose another meal. Make sure that boat crews take care where they place and how they retrieve anchors if no moorings are available. Never dump trash or plastics in the sea. Wherever you go to visit coral reefs, respect the local communities of the area and their way of life. Support conservation efforts both in your own country and in those you visit. Educate yourself about issues affecting the marine environment. Remember, it is you who can make a difference whether coral reefs survive into the next millenium. 1km 10km MBCA Menai Bay Conservation Area Guide Book MENAI BAY CONSARVATION AREA GUIDE S ARAH C URRAN

2 Contents The voice of the sea speaks to the soul. The touch of the sea is sensuous, enfolding the body in its soft, close embrace. Kate Chopin (The Awakening) Introduction 1 Zanzibar map 4 Menai Bay conservation area 5 Living on a reef - Marine life 8 Building a coral reef 9 Feeding 11 Reproduction 12 Coral aggression 12 What coral s need 14 Types of coral lifeforms 15 Types of reef 15 Coral Reef Fish 17 Common fish on a coral reef 21 Invertebrates 25 Other reef visitors 29 Turtles 29 Marine mammals 31 Seabirds 33 People and coral reefs 35 Threats to coral reefs 39 The impact of tourism 42 Ecotourist tips 44 Organisations in Zanzibar concerned with marine conservation 45 International organisations concerned with marine conservation 47 Sites to snorkel or dive in Menai Bay 49 MENAI BAY CONSERVATION AREA PROJECT ZANZIBAR Head Office: Fisheries Department P.O. Box 774, Zanzibar, Tanzania Tel: Mobitel: Fax: wwfmenai@zitec.org

3 It is not a wonder, which at first strikes the eye of the body, but rather, after reflection, the eye of reason. We feel surprised, when travellers relate accounts of the vast extent of certain ancient ruins; but how utterly insignificant are the greatest of these, when compared to the pile of stones here accumulated by the work of various minute animals. Charles Darwin Voyage of the Beagle I n t r o d u c t i o n Piles of stone are how Darwin described the overwhelming structures that are coral reefs. The bewildering diversity of life that exists in these vibrant oases is unparalleled in nature. We need only step from the face of the earth to enter a realm of such astounding colour and life, breaking the surface of the oceans to observe one of the most productive ecosystems on earth. In terms of sheer numbers and diversity of observable lifeforms these piles of stone stand alone. Darwin, so bewildered by the life found there, felt what many visitors experience; wonderment and awe as one swims, snorkels or dives in these aquatic Edens. We can float over a multitude of life forms in a cascade of vibrant dazzling hues. The visual impact is astounding. Existing between the latitudes of 30 degrees north and south of the equator, coral reefs can be found in all tropical seas where the appropriate environmental conditions are available. Conditions such as light, sun, nutrients, temperature between C degrees year round and clean clear water. The number of species on coral reefs has been recorded at around 3,000 for one reef area. This diversity is unmatched by other ecosystems on earth. The framework of the reef provides food and shelter for an enormous diversity and abundance of lifeforms. But what is the framework of the reef? Many people are surprised when they learn that the reef is constructed of tiny creatures akin to jellyfish. Creatures, part plant, part animal, that trap energy from the sun in the same way plants do, to build the calcium carbonate that is the reefs structure. These colonising organisms, called coral s, exist in a diversity of forms and colours that baffle the eye. Magnificent and intricately designed, they are the living organisms that form the oases in the otherwise nutrient desert of shallow tropical seas. This book aims to raise awareness for the visitor to Zanzibar of coral reef resources, issues that threaten their survival and health, and the coastal communities that rely on these resources. Coral reefs are often visited by tourists who see the diversity of life on some of the most healthy reefs. These areas may be few and far between. The reality is that nature s bounty is being destroyed and needs your support and action to remain the unique and magical underwater kingdom that now exists only in pockets around our coastlines. Located in the West Indian Ocean 35km from the mainland of Tanzania, Zanzibar is made up of the main islands of Pemba and Unguja. The main island of Unguja (commonly called Zanzibar) is 50 miles long and 24 miles wide covering a total area of 995 square miles. The islands of Zanzibar attract visitors from all over the world. People visit the islands for the rich melting pot of culture, romantic Arabian Nights architecture, untouched forests, rare wildlife and the idyllic coasts, bays, islets and coral reefs. The coral reefs are the mainstay of the local people providing opportunity and livelihood. Zanzibar s shores are lapped by the West Indian Ocean, a continuous region of the vast Indo-Pacific realm that stretches from the Red Sea and South Africa to Polynesia in the Pacific. It is an ocean stretching two thirds of the way around the Earth. Coral reefs, one of the oldest ecosystems on earth, are scattered across this realm. They can take the form of small shallow patch reef areas and steep drop off 1

4 I n t r o d u c t i o n I n t r o d u c t i o n reefs fringing islands, to the vast expanses of barrier reefs such as the Great Barrier Reef in Australia. The most developed reefs in East Africa are found in southern Kenya and Tanzania. Along the continental African coastline, the peak of species diversity in East Africa is probably found on the islands of Tanzania such as Mafia, and the Zanzibar islands of Pemba and Unguja. Two thirds or 600 kilometres of Tanzania s shelf are covered with coral reefs. Because of particular current systems along the East Africa coast, the islands of Zanzibar are well placed to receive more interesting or unusual species and are a rich source of marine life for much of the area. Coral reefs cover an estimated 600,000 km 2 of the globe. Their value, in terms of the genetic diversity they provide for life on the planet, is inestimable. Their economic value is easier to measure. In terms of simple economics they provide food and sustenance for millions of coastal dwellers and provide revenue for many developing nations as well as protection from storms. The coastal zone has high human settlement with the consequent increase in pressure on coastal resources. Pressures have increased worldwide in recent decades and here in East Africa is no exception. The continuing survival of coral reefs and other coastal habitats has been put seriously at risk by destructive extraction methods, over exploitation, coastal development and pollution. Zanzibar can be considered a microcosm of sorts for coastal and coral reef related concerns in the East Africa region. In Zanzibar there exist some of the most interesting and diverse coral reefs in the Indian Ocean and protection is critical if they are to survive into this new millennium. Efforts are increasing at community and government level to manage them sustainably. One such project is in Menai Bay in south west Zanzibar. An area of 470 km 2 is being managed by community and local government units facilitated by The World Wide Fund for Nature (WWF) in Tanzania. This guidebook focuses on the Menai Bay project as an example of reefs under threat and local people battling to safeguard them. It is an example of an increasing number of projects that require everyone s support. Do not forget these ocean oases when you return home, they need your help if they are to survive this millennium and if your children are to visit, as you have, one of nature s greatest creations. The voice of the surf heard now and then was a positive pleasure, like the speech of a brother. It was something natural that had reason, that had a meaning. Joseph Conrad (Heart of Darkness) 2

5 Nungwi N Mwana-mwana Tumbatu Bawe Changuu Popo Bumbwini Chapwani Kibandeko ZANZIBAR Morogo Nyange Pange Chumbe Tazari Kidoti Potowa WEST DISTRICT: Nyamanzi, Dimani, Kisakasaka, Bweleo, Fumba. CENTRAL DISTRICT: Uzi, Ng ambwa, Unguja Ukuu, Kikungwi, Bungi. SOUTH DISTRICT: Mzuri Makunduchi, Mtende, Kizimkazi Mkunguni, Kizimkazi Dimbani, Muyuni A, B, and C, Muungoni. Mkwajuni Mahonda Mbuzini Bububu Tele Ndogo Mwamba Ukombe Chaani Tele Kubwa Mnemba Matemwa Kinyasini W Pwani Mchangani Fumba Nguruwe Komonda Kiwengwa Pongwe Ndutu Ukanga Uroa Marumbi Miwi S Chwaka Unguja Kwale Ukuu Nyamembe E Mkhamvi Charawe Uzi Pungume Mwamba Mpya Muungoni Ukongoroni Vundwe MBCA Mwamba Mikunga Mwamba Kobela UNGUJA ISLAND MENAI BAY CONSERVATION PROJECT Bwajuu Muyuni Paje Jambiani Kizimkazi Dimbani Mtende Border Villages Road Land MBCA Island Makunduchi Mtende mnarani Mtende border I n t r o d u c t i o n Menai Bay conservation area Menai Bay in the south western tip of Unguja, is a popular tourist area. It s coastal resources, wildlife, isolated sand bars and rugged island scenery attract many visitors. Its proximity to the capital of Unguja Island, Stone Town means that it receives an increasing number of visitors each year. It is an important fishing ground in Zanzibar and supports nearly two thousand fishers and their families. Fishing and resource use had for many years been managed sustainably by the local populace, using traditional low impact fishing gear. However, in the late 1980s and early 1990s there was a dramatic increase in the use of destructive fishing methods. Practices such as dynamite and Kigumi fishing had devastated marine habitats and the previously productive fisheries. Seeing the destruction that resulted from such practices, and then watching their catches decline, local people took action to protect their livelihoods and the marine resources that they so depend on. The main purpose of the MBCA project is "Conserving the natural resources of Menai Bay for the benefit of present and future generations" Recent biological assessments of the area indicate that the area has degraded considerably from what it once was. Ecosystems have suffered heavily from human interference. Further, the coral reefs of Menai have also suffered from mass coral bleaching as a result of the unusually severe El Nino event of 1998, making recovery from human damage more problematic and much slower. The past use of dynamite and destructive fishing methods, fine mesh nets and intense over harvesting of nature is taking it s toll on the resources of Menai Bay. In 1995, ecological and socio-economic information was collected to pinpoint the conservation issues and concerns in Menai Bay. The World Wide Fund for Nature (WWF), an international conservation group with a local office in Zanzibar, were invited to co-ordinate activities. In the five years since their involvement began, they have, alongside local communities set up the Menai Bay Conservation Area or the MBCA as it is called

6 They were to do so by creating a conservation and management area, by reviewing legislation for protection of marine areas, by developing management systems that ensure full community participation, to produce a full management plan and to conduct research and monitoring programmes as well as environmental education and awareness. This management area covers 467 km 2 and was gazetted on the 9th August It involves 3 districts, 2 regions and 17 villages. The area is a marine park, protected by the local communities around Menai Bay, This means that local fishers protect their resources from illegal and destructive fishing. They are also involved in environmental awareness and activities to empower the community in decision making. Members of the local community attend training courses on fisheries management and conservation. The project still in it s initial stages awaits a full management plan. The main objective for the bay is to produce a multiuse zoned site where all users can be satisfied and the ecology of the area is not placed under undue stress. The marine environment of Menai Bay is under threat and there is severe deterioration and resource decline. As populations increase, so too does the demand for WHAT IS A PROTECTED AREA A marine protected area, marine reserve, marine conservation area, marine park, these are all terms for the same thing. A defined area that is usually determined by it s resources or resource use and where some form of management and control is practiced. This management may take many forms from total area closure, to no fishing zones, restrictions of certain fishing activities or use, to multiple use zoned area, to only the prevention of illegal and destructive fishing gears. Effective management needs full and active participation of the community and education is a critical component to this. Raising raise local and national awareness of the issues and the needs and benefits of marine protected areas for long term sustainability of marine and coastal resources. I n t r o d u c t i o n resources. Menai is close to Zanzibar town, a centre of increasing population and increasing tourism. Therefore as resources are depleted close by, increased demand for fish and other uses of coastal habitat activities are moving to areas like Menai Bay. High agricultural costs are also contributing to local people moving to fishing for their livelihood. Traditional fishing management is being degraded as outsiders flock to the area. Traditionally in Menai Bay, the local fisher communities practiced their own management by closing off fishing areas to allow stocks to replenish and by limiting the use of types of damaging fishing gear and practices. I n t r o d u c t i o n Recognizing that more traditional resource management was lacking, local fishers in the area formed themselves into a management committee made up of local fishers from the surrounding villages. The local community, with help and support of government departments and WWF, are continuing to work together to try to rectify the marine resource management concerns that plague the area. Although the community management committee had no formal status their original formation and work was a corner stone in trying to reclaim marine resources and take decisions in their management. In order to safeguard their resources, from local and illegal practices, the local fishers volunteered their own fishing boats to take part in surveillance activities and raised their own funds for fuel for patrols. They reached a point in the project where they needed support of government units, required technical and financial assistance. A workshop was held to discuss the issues and how stakeholders could work together. The main concerns were identified as; illegal and destructive fishing, uncontrolled mangrove harvest, low co-operation between government departments and communities. They needed increased environmental awareness, protection, training of local people in management and equipment for activities like patrolling the bay against illegal and destructive practices. The project also investigates traditional use of resources that are consistent with modern conservation and management ideas. The long term goal of the Menai Bay project is a multi-user marine park and to improve the social and economic conditions in poor communities. Management is now critical if the area is to survive and to remain productive, sustaining biological health and those of the local fishing communities relying on these resources. 6

7 MANGROVES SEAGRASS L I V I N G O N A R E E F Marine life Discussing a coral reef is not complete without looking first at the habitats that they are mutually dependent on, the mangrove forests and sea grass beds. Plant life are critical elements in coastal and marine ecosystems. As on land, they are the basis of the food web. Plants are primary producers converting sunlight into energy rich compounds for growth. They are consumed by invertebrates and fish which are themselves eaten by larger animals. The three main plant ecosystems in the proximity of coral reefs are seaweeds, seagrasses and mangroves. Seaweeds are the most abundant plant life and common along areas of beach that are periodically exposed and submerged by the tide as well as on coral reefs. They are unlike land plants in that they lack roots, stems and leaves. They appear in a diverse array of forms from branching to soft encrusting types on rock surfaces. As well as being primary producers, they also provide critical habitat for a variety of organisms. The other two main ecosystems that are linked with coral reefs are the seagrass meadows, extensive in Menai Bay, and the mangroves. Both are critical for protection of the coast as they bind sediment and soft seabed material with their root systems. They are also critical in nutrient recycling, in providing important habitat for a wide diversity of species, and as refuges and nursery areas for many coral reef inhabitants. Seagrasses are often found interspersed with reefs and are very productive areas. They have retained leaves, roots and flowers, but have evolved to be fully adapted to the marine environment. Their growth is largely restricted by light availability, in that at depth there is less light available for them to obtain the critical energy for their growth. In general, seagrass beds are found down to depths of 20m, but not deeper. They are under threat from siltation, trawling activities and seaweed farms. L I V I N G O N A R E E F Mangroves are salt tolerant trees that grow in the margin between land and sea, and are often in close proximity to coral reefs. Usually they can be found bordering estuaries and lagoons. There are ten species of mangroves worldwide with nine occurring in East Africa. Again they provide shelter and food for a large number of organisms, as well as trapping sediment and protecting coastlines. They are under extreme pressure from harvesting practices as they are cut down to provide wood for building, for fuel, to build aqua-culture ponds and for coastal development. Both mangrove and seagrass beds are critical habitats that have complex links to coral reefs. Building a coral reef This section gives an overview of the builders of the reef, the coral s themselves and other creatures likely to be found on the reefs in Zanzibar and in Menai Bay. Common and scientific names will be used for species. This is not to complicate matters or to confuse the reader, but because a variety of common names can be used for the same organism across different regions. Also, the same common name can be used for a number of different species. This means that the only surefire way to identify a species accurately across the globe is to use the international system of taxonomic names. The marine life on a coral reef is indeed vast, with around 3,000 species being recorded on one reef alone, from the coral s that build the reef s framework, to the algae and plankton, the invertebrates and fish that make up the coral reef community. The complexities of interactions between the various species on a reef is a finely balanced design. Such a series of relationships is called a food web and describes the way that energy circulates 8 9

8 around the system to keep this balance undisturbed. The food web is a complex organization of intricate relationships that must remain in balance if life on the reef is to thrive. Once this balance is disturbed, we can never be quite sure what the consequences will be. The food chain starts with the tiny microscopic plankton in the water. These tiny plants are primary producers and the equally tiny animals that exist with them in the water column, zooplankton, consume these. In their turn, the tiny zooplankton are preyed upon by larger animals like fish, shelled animals, octopus and lobsters. Even higher up the food chain, these are then eaten by larger animals such as sharks and whales. At the very end of the food chain are the decomposers that recycle the nutrients from dead and decaying matter. Coral reefs are one of the world s oldest ecosystems and they are truly ancient. These bizarre half animal, half plant organisms first appeared in the world s seas around 450 million years ago. These early forms are now extinct and the coral forms we see on reefs today evolved relatively recently, around 25 million years ago. There are around 800 reef building coral species world-wide, and around 140 of these occur in East Africa. The warm, clear waters found in tropical seas year round, are essential for the coral to produce the large amounts of limestone required to build coral reefs. Most people have a picture in their mind of what a jellyfish looks like, but few will be able to picture the creature as a coral. These marvellous organisms are relatives of jellyfish and sea anemones, and are known scientifically as cnidaria. The individual coral organism looks somewhat like an upside down jellyfish and is called a coral polyp. Each of these tiny polyps sits in a cup-like structure and are connected to their neighbouring polyps in the colony by a thin sheet of tissue. They secrete a limestone foundation providing support and protection for the colony. The tissue forms a layer of living tissue over the block of limestone they have secreted. SIMPLIFIED FOODWEB ON A CORAL REEF L I V I N G O N A R E E F L I V I N G O N A R E E F What makes corals the remarkable organisms that they are is a masterstroke of evolution. Hard corals have evolved, through time, a very special relationship with single celled algae called zooxanthellae. It is the zooxanthellae living in the coral tissues that are responsible for giving coral the rainbow of colours and shades we see on the reef. Without the presence of the zooxanthellae in their tissues, corals would appear dull and look quite lifeless, and without them the vast limestone structures would not be remotely possible. Many people are surprised that such vast structures as coral reefs are really the product of the labours of these tiny jellyfish like creatures. Not all coral s are responsible for building the reef. Corals can be conveniently divided into reef building (hermatypic) and non-reef building corals (ahermatypic). The hermatypic reef builders require sunlight to live and thrive and are therefore restricted to around the first 70m of the sea s surface. Non-reef builders (ahermatypic) can normally live without sunlight and are usually found at deeper depths. tentacles gut opening gut stomach cavity expanded coral polyp with tentacles THE BASIC STRUCTURE OF CORALS Feeding The zooxanthellae are the key to the success, abundance and diversity of life on coral reefs as they are able to utilize sunlight and carbon dioxide to produce energy rich compounds. Like plants on land, they are the first link in the food chain of coral reefs. Zooxanthellae consist of chloroplasts just as plants contain the pigment chlorophyll. In the same way plants synthesize food products through the process of photosynthesis, zooxanthellae synthesize carbohydrates for the coral host. It is 10 11

9 12 L I V I N G O N A R E E F this ability to produce their own food from the products of sunlight that enables corals to grow into such large colonies. There are species of table corals that can grow up to 10 cm a year and the rapidly growing staghorn up to 15 cm a year. Other larger massive coral life forms can reach 8 metres in height with only a growth rate of 2 cm diameter and 1 cm height a year, Such colonies can be hundreds of years old. Our hard working reef building corals actually have access to two sources of food. Firstly, as we have already discussed, they can feed by synthesizing their own food by the zooxanthellae in their tissue. They can additionally feed by sweeping zooplankton caught on stinging tentacles, into their mouths. The non reef builders do not have access to the nutrient supplying zooxanthellae so like their relations, anemones, rely solely on paralyzing and capturing organisms with their stinging cells. Reproduction Like all creatures, corals must have a strategy for reproduction. This can occur in two main ways; either through asexual or sexual reproduction. Asexual reproduction occurs by budding where the parent plant divides into two, and no fertilisation takes place. Sexual reproduction, occurs where the male and female polyps release male and female cells into the water column where they become fertilised. The resulting young coral, or planulae, will drift in the plankton until it finds a suitable site to settle and grow. One disadvantage to spawning into seawater, is that there is a danger of the male and female sex cells being lost or washed away in the water column before the female cells can fertilise. But coral, or rather evolution, has thought of this too and different colonies of the same species will spawn at the exact same time, to reduce the risks of sex cells being lost before fertilisation. Such mass spawning has rarely been documented but on the Great Barrier Reef in Australia, sex cells are released at the same time each year, after sunset on a full moon in November. Coral aggression Corals, giving colour and form to the reef, appear to be benign, sedentary creatures unlikely to engage in conflict of any type. But surprisingly corals do show signs of aggression between species. Like all organisms, they must defend themselves and their resources from potential L I V I N G O N A R E E F threats. This is most evident to the observer when we see one colony overgrowing another as they compete for space on the reef. What is more akin to aggression as we understand it, are the nocturnal battles that ensue between species as corals extend their tentacles up to several centimetres away. They either digest the tissues of neighbouring species or, using their specialized stinging cells, nematocysts, sting the adversary until it retreats. For the human visitor to the reef the obvious results of such battles are dead margins where colonies have been successfully pushed back by another species. The stinging cells of coral polyps are not only for attacking or hunting but they also provide protection from other organisms living on the reef, such as fish and invertebrates that feed on them. One of corals greatest predators is the Crown of Thorns starfish (Acanthaster plancii) that feed on live coral and causes a large amount of damage in areas of high Crown Of Thorns densities. The coral have little or no defense against such a voracious predator and large areas are wiped out by this species. T HE RESULT OF NOCTURNAL BATTLES BETWEEN CORAL LEAVES THE DEAD MARGIN BETWEEN THE ADVERSARIES C ROWN OF T HORNS IS A VORACIOUS PREDATOR 13

10 A PRODUCTIVE REEF WITH HEALTHY CORALS AND HIGH DIVERSITY OF FISH L I V I N G O N A R E E F What corals need The reef crest is usually the most productive and diverse zone on the reef, being exposed to currents, waves and clear warm shallow water. A single coral reef can support an incredible diversity and abundance of species. Yet this astounding productivity occurs in waters that are otherwise devoid of the essential nutrients required to support life. Coral reefs are a true oasis in an ocean desert. For corals to fulfill their great potential for productivity, they require certain specific conditions to thrive; high light availability, the correct temperature,salinity range, wave action, low sediment loading and the correct tidal conditions. Light is required, as we have said, for the zooxanthellae to be able to photosynthesize and produce food for the coral polyp. Water visibility can be anything from less than a metre in areas subject to sediment where the sea is stirred after heavy storms, to in excess of 50 m in the open ocean. The availability of light in different areas determines the depths at which corals are found, as different species thrive under different light conditions. On the whole though, we can say that coral s are restricted to the upper 40m of reefs where light is at its optimal for coral development and growth. Linked to depth of coral growth is temperature. The best conditions for coral growth is between 20 to 28C degrees and this factor again controls the growth and development of a reef. Salinity, i.e. the amount of saltiness in the water, too high or too low, can affect growth of coral. Low salinity can occur, for example, in areas close to rivers where fresh water flows into the sea. This means that coral reefs do not form in the close vicinity of rivers. Wave action is another important controlling factor as areas that are exposed to large waves need to be hardy, sturdy species and are usually stunted in growth. Corals take many diverse life forms depending on species and environmental conditions. For example short sturdy forms are found in wave exposed areas, more fragile, branching forms can grow where conditions are calmer and less exposed to weather conditions. Some types of coral life forms are termed massive, branching, table, plate, staghorn and foliose, but they are all builders of the reef. L I V I N G O N A R E E F Types of coral lifeforms Tidal ranges control how many nutrients are transported and time of exposure to intense sunlight and air where corals can dry out or dessicate. There are a number of types of sedimentation on and in the vicinity of reefs. Silt (particles of matter and seabed sediment), can arrive on reefs through river systems, from land after development activities or through the cutting of forests, landslides, and dredging the seabed. This sedimentation is carried on the reefs where they become smothered and essentially choke to death. Sedimentation can also reduce light availability, and without light, as we have learned, corals cannot grow. This is perhaps one of the greatest threats to reefs worldwide, as it is almost impossible to prevent once it has begun, and the damage is long term. Types of reef Charles Darwin, one of the founders of the theory of species evolution, first saw coral reefs on his historic voyage of discovery of nature on the HMS Beagle. Fascinated by the life found there, he turned his thoughts to the way in which reefs are formed. No easy feat without modern technology, computerized mathematical models and the geological and biological data now available. But, come up with a theory he did, and to this day, Darwin s theory of coral reef formation stands. In fact more than 100 years later, his theory was put to the test and drill cores from Eniwetok atoll in the Pacific confirmed his volcanic origin theory BRANCHING(1}, MASSIVE(2) AND FOLIOSE CORAL(3) 14 15

11 T Y P E S O F R E E F There are three types of coral reefs that exist; fringing, barrier and atoll. They are essentially varying stages of evolution of the same reef. The coral grows around a volcanic island this is the fringing reef, and as that island sinks coral growth increases upwards in an effort to gain sunlight, thus producing the barrier reef with a lagoon between the island mass and the reef. Further land subsidence as the island disappears below the water, gives rise to what is called the atoll. The diagram below illustrates this. Coral Reef Fish Coral reef fish are the most dominant and visually obvious lifeforms on a reef. All divers and snorkellers have experienced the bewildering display of shapes, sizes and colour of reef fish, and there is an equally bewildering diversity of behaviours. Most reef fish are what are called bony fish as opposed to cartilaginous fish, such as rays, sharks, jacks. The term bony means that the skeleton is made of bone. These bony fish usually have specialized fins that enable them to be exceptional swimmers. Further, they possess a swim bladder which is used for hearing and to control buoyancy. To the human visitor on a coral reef, the quality and diversity of the reef can be measured by its numbers and variety of fish. There are an estimated 12,000 marine fishes and around 7,000 occur on or near coral reefs. Coral reefs harbor the highest number of fish species in any aquatic habitat. Every conceivable ecological niche is occupied by a species of fish. 16 MENAI BAY CORAL REEF GUIDE 10 17

12 C OMPRESSED FOR EXAMPLE B UTTERFLYFISH AND A NGELFISH F LATTENED TOP TO BOTTOM SUCH AS RAYS 18 C O R A L R E E F F I S H There is an astounding number and variety of fish but it is possible to learn to identify common species and the main families through their body shape of which there are four forms Fish can be further classified by their place in the food web of coral reefs. They can be considered as herbivores, feeding on plant material like our cattle on land, omnivores, like humans feeding on both plant and animal matter, or carnivores that feed exclusively on animal matter. And there is a further category; corrallivores; these are essentially the same as omnivores but they specialize on feeding exclusively on coral s (which are themselves a combination of plant and animal). S LENDER AND SNAKE- LIKE, SUCH AS EELS T ORPEDO SHAPED FOR F AST SWIMMING SUCH AS BARRACUDAS, JACKS AND TUNA Fish do however have one thing in common, almost all display a dazzling array of bold colours and designs. Why this is so has baffled biologists for many years. It is now clear that colours are used for all sorts of reasons in the complex environment of the reef. Colour plays a major role in the life of fish, in predation avoidance, camouflage, for defense, communication between and within species, and in courtship. Many species change from juveniles to adult forms. This is especially true for angelfish and butterflyfish. The photo shows the semicircular angelfish (Pomacanthus semicirculatus). The juvenile fish is marked with bright blue curved bars on a dark background that fade away as it reaches adulthood. Biologists interpret this as the fish using colour to disguise the young of species from adults so that they can live within and near the territories of mature adults without attack. J UVENILE AND A DULT ANGELFISH C O R A L R E E F F I S H Since many reef fish are hermaphrodite colour is used to signal the onset of sex change to other individuals. For example, wrasses and parrotfish are hermaphrodites throughout their life cycles and may pass through five or six colour stages. The last phase may even be a different shape for example the fairy basslet (Anthias squammipinnis). Colour is also used to indicate social status and hierarchy so that reef fish can behave appropriately so exist together without undue conflict within their own communities. Colour can also function in the same way that expression does in humans, indicating changes in emotional state. It is usually quick colour changes that fulfill this function. Mimicry and camouflage are other common uses of colour in the reef fish s world. Some use colour, design and body shape to mimic another species to pretend to be toxic when it is not at all. An example is the juvenile Pinnate bat fish (or spade fish), Platax pinnatus that pretends to be a toxic flatworm. Another (Platax orbicularis) resembles a floating leaf in both appearance and behaviour and is found amongst mangroves and lagoons. Mimicry is also used to gain access to food for example, cleaner wrasses (Labroides species). These small fish help other reef fish in ridding themselves of parasites and in the process have a hearty meal. But the almost identical false cleaner wrasse, (Aspidontus taeniatus), uses its remarkable charade to get close to unsuspecting fish and nips off pieces of fins, skin and scales. Divers and snorkellers can observe the expression of surprise and even outrage when a parrotfish allows itself to be cleaned by what he assumes is a harmless and beneficial cleaner wrasse only to be bitten painfully on the rump by the false cleaner. Perhaps one of the most well observed examples of using colour for camouflage is when a diver comes to the surface saying they have seen green, yellow, brown and striped forms of the trumpet fish, (Aulostomus chinensis). All these multi-colored fish are in fact probably the same individual seen in a variety of situations. The trumpet fish can imitate a range of animals and plants by altering its colour rapidly. It will then swim with fish schools, individual fish or lie by corals. M ALE ( RIGHT) AND F EMALE Anthias SHOWING DIFFERENT B ODY S HAPES BETWEEN THE SEXES (not to scale) TRUMPETFISH IN YELLOW FORM HIDING AMONGST CORAL 19

13 20 C O R A L R E E F F I S H Scorpion fish and frog fish are also well known masters of disguise and often lay camouflaged on coral patches or on rock, largely invisible to the eye. Many fish routinely change colour as they swim off the reef and become a shade to blend in with the monochrome sea off the reef, then changing once more as they return to a patch of coral. Reef fish display an enormous almost endless variety of behavioral adaptations to help them survive and thrive. Many of these have been mentioned and for further information I will refer you to the books listed at the end of this guide. Some species evolve or develop a special relationship with other species on the reef. These relationships are called symbiosis meaning living together. There are three main types of symbiosis depending on the degree that the species benefit from the relationship. These are mutualism, where both benefit equally, commensalism, where one benefits more than the other, and parasitism when one benefits to the detriment of the other. The most extreme case is where the parasite causes the death of the host. There are numerous examples in the reef environment and you can observe such relationships. There are a couple of common associations that anyone who has snorkeled or dived will have observed. Shark suckers (Echeneis naucrates) are fish that have a modified sucker on their heads and are often seen attached or associating with larger animals on the reef such as sharks or turtles. They will also sometimes successfully attach themselves to humans. The sucker fish benefits by gaining shelter from the larger animal. It is less likely to become prey for anyone else if it is attached to a shark for example. It can also forage on scraps of food leftover from the larger animals feeding. In return it is thought that the larger animal has small parasites and dead skin removed by the sucker fish. Common fish on a coral reef Anemonefish Anemonefish, commonly called clown fish because of their striped markings, are a common sight on a reef as they weave in and out of the anemone s tentacles. Interestingly all species of anemone fish have their own specific species of anemones that they will always associate with. So how does this relationship work. The anemone fish are immune to the stings of the hosts tentacles. They achieve this by rubbing themselves on the underside of the anemones and coat themselves in a mucous layer that prevents the release of stinging cells. In return for shelter and the anemone s defense against predators, the fish fulfills its part of the bargain by guarding the anemone by sometimes aggressively attacking creatures that come close, as many divers will testify. It is also thought that the fish clean the host of parasites. Grouper Groupers vary in colour but are most often brown, grey and blotched. They are a prized food fish, and can reach large sizes. Groupers have a formidable set of teeth but are unlikely to be a threat to divers beyond a sharp shock if meeting a full grown adult face to face. They spend their days under ledges, corals and in caves, and rely on ambush tactics for hunting. A NEMONEFISH AND HOST T HE PEACOCK GROUPER (Cephalopholis argus P ARROTFISH 21

14 C O R A L R E E F F I S H C O R A L R E E F F I S H P ARROTFISH (juvenile Scarus spp) S POTTED S WEETLIPS (Plectorhincus spp) T ITON T RIGGERFISH (Balistoides viridescens) CLOWN TRIGGERFISH (Balistoides conspicillum) Parrotfish These vibrantly coloured fish come in shades of blue, green, purple, pinks, and are often seen grazing algae or nipping at coral on the reef. There are different markings between male and female and juveniles. This makes identification of parrotfish particularly difficult. Parrotfish can grow up to 130 cm such as the enormous bumphead parrotfish. Parrotfish have strong throats that grind coral and rock to help in digestion. The ground up rock is a major source of sand on the reef, and divers often see parrotfish expelling this. During darkness parrotfish may be seen wrapped in a mucous sleeping bag or cocoon. This is thought to hide their scent from predators and so let them rest safe and sound. Sweetlips These large fish are related to snappers, and can grow up to a metre in length. Their thickened lips give the fish their name and they can be distinguished from other species by this feature. Some juveniles display a dramatic colour alteration as they become adults and swim with a very distinctive undulating almost comical gait. This may be to imitate toxic flatworms, or perhaps it is just an unattractive swimming motion to predators. The adults are fairly inactive during daylight hours and can be seen on the reef sheltering under ledges and by coral heads. Triggerfish Triggerfish are so called because of their ability to lock into place a modified dorsal spine when under threat. They will escape into a crevice or cave and lock the first trigger into place in a way that it cannot be pulled out of the crevice it is in. Males fiercely guard eggs once laid and are very territorial. The Titon triggerfish, may attack divers if it feels threatened. They are usually wary but divers must heed their warnings not to get too close. Angelfish Angelfish have similar body shapes to butterflyfish, are very colourful and are often confused with them. Juveniles are often found amongst rocks and adults are more often seen in rich coral areas, sometimes peering out of caves or ledges. They feed largely on sponges, invertebrates, algae and fish eggs. Unicornfish Unicornfish are a type of surgeonfish that get their name from the two sharp spines on either side of the body at the base of the tail. These spines are sharp like a surgeon s knife and dangerous to the unwary diver or fisherman if they are touched. They become erect when the fish feels threatened or stressed and can inflict severe injury. The bignose unicornfish is found in midwater groups near the reef edge and feeds on zoo-plankton. Interestingly it can turn its vibrant blue markings on and off at will. This is used especially in courtship when the male is brightly marked. Moorish idol A relative of the surgeon fish, this species is unusual in that it is the only species in the family Zanclidae. It s distinctive shape and colouration is well known on reefs. Although a close relative of surgeonfish, they are lacking the sharp blades at the tail s base and have a more elongated snout. They are often seen in small groups but sometimes in larger schools. They feed mainly on sponges. Butterflyfish These fish are small and disc shaped and are one of the most common and obvious shapes on a reef. They are very colourful and are often seen in male and female pairs. Many feed on live coral and for this reason they are often considered indicators of reef health. Most species will patrol a specific area, it s home range that it defends. Those occurring in pairs will remain together for years, often for life. R EGAL ANGELFISH (Pygloplites diacanthus) B IGNOSE UNICORNFISH (Naso vlamingi) M OORISH IDOL (Zanclus cornatuspic) R ACOON BUTTERFLYFISH (Chaetodon lunula) 22 23

15 L IZARDFISH (Synodus variegatus) C O R A L R E E F F I S H Lizardfish Named because its looks very much like a lizard sunning itself as it sits perched statue like on ledges, rocks and rubble propped up on its front (pectoral) fins. It s camouflage is perfect for ambushing small unwary fish as they swim within reach of the lizardfish. Soldierfish Very similar to the squirrelfish in body shape, colourings and habits and are recognized by their large eyes. These are a clue to it s nocturnal habits. It is most often seen during the day, under ledges or at the mouth of caves in groups, hovering in the current. S OLDIERFISH (Holocentridae spp) B ANNERFISH Y ELLOW TOP FUSILIER (Caesion xanthanota) 24 Bannerfish Often confused with moorish idols because of their colouring and the elongated dorsal fin. These butterflyfish (pennant butterflyfish) are seen singly or in groups around the reef feeding on corals. Fusilier Fusiliers are often brightly colored and are usually seen in schools on the edge of the reef. They are also commonly in mixed schools with other species occurring together. These schools swim round the reef and on a dive the same groups will be seen several times as they feed on plankton in the water column. Wrasse (not pictured) Close relatives of parrotfish, this family is large and diverse which makes species identification difficult. They are often mistaken for parrotfish, with similar body shapes and hues, but their lips are slightly thickened and very unlike the beaks of parrotfish. Like parrotfish they also change colour with sex and age. They are inactive at night and are seen commonly on reefs. Invertebrates There are multitudes of invertebrate animals, i.e. those without a backbone, on coral reefs, each with its own particular niche and contributing to the complexities of life and stability of the reef ecosystem. Invertebrates are an incredibly diverse group covering a vast number and array of lifeforms. This group makes up around 95% of life on the planet. The greatest variety of invertebrates exists in the sea. Evolution, as opportunistic as ever, has taken advantage of the buoyancy that seawater provides and of the large expanses of seabed that are excellent habitat for many invertebrates. They are an integral part of the life and functioning of the reef. Their many forms are often quite alien and just as beautiful. Their diversity is astonishing, for example, in the group that makes up the echinoderms; the sea cucumbers, sea urchins and seastars, there are over a thousand species. Many invertebrates are nocturnal, only active at night while others are, like many fish, hidden in crevices, caves or under ledges by day. Some live in symbiosis with other reef inhabitants, commonly living in the structure of sponges, corals, basket stars, with fish like the anemone and clownfish. Many can change colour for defense, camouflage and communication, like the cuttlefish and octopus. Still others are able to steal the toxin from coral polyps to use for themselves. The group is immense and here we can only touch on some of the wonders of invertebrate life. MENAI BAY CORAL REEF GUIDE 25

16 C UTTLEFISH I n v e r t e b r a t e s Perhaps one of the most obvious invertebrates to visitors to a reef are the cephalopods, the octopus, cuttlefish and squid. These remarkable creatures have a learning ability that far outstrips other creatures on the reef from fish to invertebrates. Learning in invertebrates is as varied as their forms and lifestyles. Octopus and cuttlefish are well known for their intelligence and their ability to learn very quickly from experience. They both possess complex brains and excellent vision. CUTTLEFISH When the young cuttlefish hatch they are already adept at feeding and defense, immediately burying themselves in sand, and able to expel black ink in defense to hide itself while it escapes. Young cuttlefish will also recognize their food, shrimps, immediately. As they grow, they learn, by trial and error, to capture larger species like crabs, quickly discovering the best angle of approach and ambush. FAN WORMS FAN WORMS The main groups of invertebrates that we will see on a reef are: Sponges (Porifera) Segmented worms (Annelids) Flatworms (Platyhelminths) Crabs, lobster, shrimps, prawns (Crustaceans) Squid, shellfish (Molluscs) Starfish, sea cucumber, sea urchins (Echinoderms) Seasquirts (Tunicates) Seamats (Bryozoans) Cehalopods (Octopus, cuttlefish) Other not so readily observable lifeforms are thought just as fascinating and critical to the reefs survival. A common sight are the fan worms, or feather duster worms that emerge from coral and rocks, like flowers and miniature Christmas trees scattered across the reef face. Their tentacles poking out of their tubes catching food suspended in the water. These worms react to water movement or shadows by quickly retracting back into their tubes. Any diver will know that as they pass a hand over the fan, it is pulled back into safety in a split second. They are food for fish largely and are favoured especially by the butterflyfish. I n v e r t e b r a t e s SPONGES Giving colour and texture to the reef, sponges come in a large variety of shapes, colours and sizes, and there are more than 5,000 species. Originally, biologists classified sponges as plants. We now know that they are animals, albeit very simple bodied. They are commonly found living under rocks and crevices where there is less light competition. Like corals they come in a variety of body forms depending on species and environmental conditions; branching, columnar, encrusting, spherical. They are constructed like sieves and have no real internal organs but specialized cells to filter food out of the surrounding seawater. Water is filtered to obtain organic food and nutrients. The remaining water is then expelled through the larger opening on the body surface. Sponges play a critical role in the coral reef ecosystem and provide habitat for a number of other marine organisms as they are attached permanently to the reef so other small invertebrates can inhabit their body structure. D IVER AND B ASKET SPONGE( ORGAN PIPE) Organpipe sponges are clusters of hollow tubes resembling the pipes on an organ and can reach 30cm in height. A sponge 10 cm in height can filter around 150 litres of water a day. NUDIBRANCH Nudibranchs, commonly called seaslugs are the beautiful tiny creatures found in all oceans especially in the tropics. They litter coral reefs but you may well miss them if you do not look closely at the microlife that exists on the reef. They are found feeding on coral polyps and grazing algae on rock surfaces and come in such a dazzling variety of colors and designs they are one of the most spectacular creatures found on coral reefs. ORGANPIPE ORGANPIPE 26 MENAI BAY CORAL REEF GUIDE 27

17 S EASLUG S EASQUIRTS G IANT CLAM 28 I n v e r t e b r a t e s Like many species on the reef, nudibranchs are toxic. They feed on corals but how is it that they do not get stung? Well, they are able to take the stinging cells of corals and store them on their back in a sack-like structure called the cerata. The animal then uses the stinging cells to ward off their own enemies. A cunning and successful strategy for what is sometimes a life fraught with dangers. SEASQUIRTS Commonly called seasquirts, tunicates are superficially similar to sponges and are often mistaken for them. However the seasquirt is a more advanced lifeform possessing a gut, heart and a circulatory system. Strictly speaking tunicates exist somewhere between the world of invertebrates and vertebrates. Around 3500 species are known, found at all depths and many are probably still undiscovered. The young seasquirt is like a tadpole swimming through the sea until a suitable place is found to settle. The adults that we see are sacklike organisms encased in a tunic - hence their name tunicates, and are attached to rock or corals. Many divers know that when touched or feeling stress these animals will contract and force water out of their siphon, which is where the group gets its common name. Seasquirts have elicited great interest of late from the pharmaceutical industry as many have proved to be antifungal, antibacterial and even anticancer agents. GIANT CLAM These belong to the bivalve group meaning a shell with two parts held together with a hinge. There are seven species in the IndoPacific and three occur in the West Indian Ocean. Giant clams (Tridacna) are very unusual and unlike other bivalves. Like other marvels of life on the reef, giant clams have evolved a relationship with symbiotic algae in the same way that coral have. The algae grow in the mantle (lips) of the clam and are responsible for synthesizing food from sunlight. These algal cells are also responsible for giving the giant clams the magnificent iridescent hues so familiar on the reef. The great sizes of giant clams (up to a metre or more across) is solely the result of this relationship. They are reported to live to over 100 years. When under threat the clams protect the delicate tissue of their bodies by snapping the shell closed. It is virtually impossible to open this shell until the giant clam is satisfied it is safe to open up. Other reef visitors As well as the corals, fish and invertebrates that live on the coral reef, there are also other marine creatures, some resident and other less frequent visitors. The main ones of these are the marine mammals and turtles, and the seabirds. Turtles Marine turtles are commonly seen resting on the reef or feeding on soft corals and sponges. These ancient mariners glide around the reef spaceship like, moving just a few feet when disturbed or cruising off the reef into the gloom. It is a thrill for any diver or snorkeller to see one of these ancient sea creatures. Air breathing reptiles, they have roamed the oceans unchanged for millions of years. There are eight species of marine turtles worldwide, six of which occur in the Indo Pacific. In Zanzibar and Menai, two species are the most common. These are the green and hawksbill turtles (Chelonia mydas, and Eretmochelys imbricata respectively). They spend almost their entire lives at sea except when the females come ashore to lay their eggs. Turtles travel vast distances throughout their lives and often return to the very same beaches that they were themselves hatched on. Individuals will take around 30 years to reach maturity. 29

18 O T H E R R E E F V I S I T O R S H AWKSBILL TURTLE They are a slow growing species and breed every two years laying around eggs in each clutch. When turtles come to local beaches to lay eggs, they are at their most vulnerable and are easy prey for local people to kill as the females haul themselves to the beach to lay their clutch. Eggs are also collected. As well as humans taking turtle eggs, the eggs and the new hatchlings that appear two months later must avoid the army of obstacles such as dogs, lizards seabirds, monkeys, rats and fish etc as they scramble into the ocean. All species of marine turtle are protected under CITES (The Convention on Trade in Endangered Species of Wild Fauna and Flora) and are considered as endangered. Under tanzanian law, their harvesting and killing is illegal. Unfortunately these wonderful ancient creatures are under enormous threat from humans indirectly from habitat degradation and pollution, and from direct kills and egg collection. Marine turtles are also killed incidentally in fishing nets. They are used for food and sold as curios with their shells being used for jewelry. Such activities have caused large scale damage to populations. In the sea, plastic bags are often ingested by turtles, mistaking them for jellyfish, a favored food source. Ingestion of plastic causes them to choke with fatal consequences. In Zanzibar, even though the trade and harvest in turtles is illegal, they are still harvested for food, and their eggs are still collected from laying beaches. Their shells are used still in the curio jewellry trade. G REEN TURTLE Marine mammals Marine mammals are not strictly coral reef animals but are often seen on or near a reef, taking advantage of the exceptionally high productivity around coral reefs. Marine mammals, whales and dolphins, are air breathing mammals like ourselves. There are two main species likely to be encountered in Menai Bay. These are the bottlenose dolphin (Tursiops truncatus) the dolphin that is most often seen on television and the friendly solitary dolphins that occur. They can achieve swimming speeds of 25 miles an hour. The other species often seen in mixed schools with bottlenose dolphins are the humpbacked dolphins (Sousa chinensis). The Bottlenose dolphin The Bottlenose dolphin (Tursiops truncatus) is a classic dolphin shape, with a short beak or snout, tall dorsal fin and a brown, grey or silver colour. They will usually form groups of between ten to thirty or so although there are sightings of large herds ranging in the hundreds reported from more offshore areas. Their life history is not dissimilar to humans, with young reaching maturity at around 12 years of age. Gestation is 12 months 30 31

19 BOTTLENOSE DOLPHINS DOLPHINS SWIM IN F AMILY GROUPS AND ARE OFTEN SEEN BREAKING THE SEA S S U R F A C E D OLPHIN WATCHING 32 O T H E R R E E F V I S I T O R S and females will bear only one calf and this every second or third year. In dolphins nursing will last for a couple of years and other adults will baby-sit while the mother searches for food. They use a system of sonar called echolocation for communication between themselves and in hunting for food, using pulsed soundwaves. Bottlenose dolphins are more ready to bowride than other species, swimming towards vessels for a free and fun surf on the bow wave. They are often seen body surfing for what is apparently no reason except pure fun in the rougher waters near shore. Humpbacked dolphin Humpbacked dolphins (Sousa chinensis) are very similar to bottlenose dolphins. The animal appears grey or tan colour. Although they are often in mixed groups with bottlenoses, the species is less likely to bowride although it does occur but they are generally less approachable than bottlenose dolphins. One of the major threats to the dolphins is by direct takes. This is killing dolphins directly for food. In dolphins were taken by fishermen in Kizimikazi for use as shark bait. Dolphins are also killed by incidental capture in nets where they drown. Degradation of their habitat and food resources is also occurring. While dolphin watching is a unique experience and recommended by many previous visitors, there can also be detmental effects resulting from this activity if tour operators do not adhere to common sense guidelines. Threats to dolphin populations are a result of growing numbers of boats, which increases stress levels and can in turn cause physiological stress and disease. Boat drivers must be fully aware of simple facts such as that separating calves from mothers will increase the likelihood of collision. Responsibility for environmentally sound behaviour also lies with the visitors themselves especially when swimming with the dolphins. Obviously dolphin schools will feel more threatened if there are calves with them thereby increasing stress levels. There is now a move towards tighter controls on the dolphin watching industry in order to make sure that populations remain healthy and viable. O T H E R R E E F V I S I T O R S Seabirds Most people on visiting a coral reef are consumed by what they are seeing underwater and pay little attention to the creatures above water that are just as much a part of the ocean ecosystem. Take some time out to look above you and you may see some N ODDY TERN of the seabirds that are also attracted by the rich productivity of the seas around coral reefs. Common species are the reef heron that you will commonly see wading around the shallow waters as the tide laps at their feet. Scouring the sand for invertebrates and small fishes. G REATER CRESTED TERN Herons too are seen wading along reef flats, scouring the sand for invertebrates. They are especially present in the early morning at dawn and at dusk in the evening. Terns are also common visitors and can often be seen in groups flying in graceful formation over the oceans before plunging, torpedo like, into the sea to capture small fish sighted from above. Noddy terns are a chocolate brown colour with a distinctive pale patch on the head. They are more often seen in the open oceans or breeding on remote offshore islands. 33

20 34 P E O P L E A N D C O R A L R E E F S The ring of living beauty drawn about our shores was a very thin and fragile one. It had existed all those centuries solely in consequence of the blissful indifference of man. Edmund Gosse (Father and Son) P E O P L E A N D C O R A L R E E F S People and coral reefs Exploitation and use of coral reefs and other marine resources is not a recent phenomena. Humans have harvested and utilized marine resources for as long as we can trace back into history. However, until recent times their use had been limited or managed by traditional beliefs, that protected their resources. These included forbidding the direct kill of dolphins because of special magical powers, limiting the number of turtle eggs taken, leaving areas of sea fallow so that fish stock could recuperate and protecting village owned areas of reef. But this indigenous and traditional management is, for a variety of socioeconomic reasons, now being discarded leading to severe depletion of resources. Research in Kenya and Tanzania indicate that human activities have affected productivity on 30-40% of reefs. Zanzibar is suffering like most of the region from increasing coastal populations and expanding development of urban areas and tourism facilities along the coast. Coastal communities can be defined as those people living alongside the margin of land bordering the seas bays and islets of the coast. They depend for their livelihoods, and to a large extent their survival, on the POPULATION GROWTH INCREASES THE NEED FOR ENVIRONMENTAL EDUCATION near-shore coastal and marine resources available. These are the rich productive mangrove forests bordering the coastline, the seagrass beds and coral reefs. Although we talk about an area as the coastal zone, defining it s boundaries are problematic because activities on land effect marine and coastal ecosystems. Think of the large scale cutting of forests in the uplands. As trees are cut, the land and soil that they have for so long bound together becomes unstable. The ground is loosened and at the onset of rains, this loose matter is washed down to the coastline. Mangroves, designed by nature to help trap such sediment from land and so act as a buffer for seagrass and coral reef ecosystems, are also cut down for firewood and building materials. The buffer system that nature has so perfectly designed is lost and sediment runs freely down the mountains, seagrasses and coral s become smothered and die. As habitat is degraded, so too is the life that exists on it as critical resources, such as food and shelter, cease to exist. So protecting coral reefs means managing land practices as well. Marine ecosystems do not have the same boundaries as on land, they are continuous, fluid and merging. Trying to partition 35

21 P E O P L E A N D C O R A L R E E F S areas for protection in the sea is far more difficult than designing our nature reserves on land. Habitats in the ocean are linked by larval transport, nutrients and pollutants because of the mere fluid nature of the medium called the Sea. What happens to a reef in one area may well effect a reef tens or even hundreds of kilometres away. Take for example a reef in western Zanzibar that, because of current flow, happens to be supplying a reef in Southern Tanzania, more than 400 miles away, with coral larvae. As the reef in Zanzibar is smothered by siltation because forests on land are cut down, coral dies, ceases to reproduce, no larvae flows to the southern reef. There is no new coral being supplied. A tropical storm hits the southern reef causing large areas of reef to die. After sometime it still shows no signs of recovery because its supplier, in Zanzibar, is out of business. Coastal communities are reliant on these resources for food and security. Fishing villages are often poor with inhabitants living in crowded and impoverished conditions. The people have little power and voice with which to alter their social and economic situation. Fisher communities are often migratory. In many countries, such as Tanzania, there is an escalating population that is pushing what are traditionally inland people to the coast, as they pursue the improved opportunities available from the ocean s traditionally bountiful, and free resources. As well as there being less restrictions than on land, the seas are largely viewed as a resource that is open and freely available to everyone. P E O P L E A N D C O R A L R E E F S Often as people move to the coast they have no traditional ties with an area, and little indigenous knowledge about its ecology. They may also not traditionally be fishers, so have little understanding of the sea and how to let it remain bountiful. With less understanding they are therefore poorly equipped to manage resources in a sustainable fashion. As poverty in coastal rural areas increases, especially so in areas of high population growth either through birth or the effects of immigration, fishing and harvesting practices become increasingly destructive and unsustainable. The main concerns from fishing villages that threaten coral reefs today are; the use of dynamite, fishing with small meshed nets, using nets that drag on the coral, over-fishing, spear fishing, anchor damage, collection of reef organisms for the curio trade, coral mining, pollution (increase in waste/sewage), siltation, poor agriculture in coastal lands and the deforestation of mangroves. Dynamite fishing, for example, was rampant in the early 1990s in Zanzibar. It still occurs but is much reduced and is now restricted to more remote and uninhabited reef areas. Unfortunately these are likely to be the most pristine and damage will go unchecked because of their remoteness. Destructive fishing practices are likely to C OMMUNITY P ARTICIPATION IN R EPLANTING OF M ANGROVES become more common as fishers become more desperate to increase returns from a dwindling resource base. There are already indications of over exploitation of coral reef resources, overfishing and habitat destruction. As poverty rises in coastal populations, so too does pressure on near-shore resources. Local people become locked in a cycle of resource depletion and increasing poverty. The solution to these problems is becoming increasingly clear. It is to involve local communities in the management of resources in a process of community based coastal resource management. Coastal peoples are the real day to day managers of the resources and their livelihoods are at stake if such resources are destroyed. They are often unaware of options available or lack the knowledge and skills to protect resources. They may feel powerless and with little support. They may lack technical equipment such as boats for patrolling the areas against illegal fishers. Perhaps they require know-how to help with setting up alternative livelihoods, to alleviate pressure from fishing practices, and technical advice on setting up protected sites and managing their resources. The traditional and indigenous knowledge they have can be invaluable in understanding an areas ecology and aid in formulating management plans. 37

22 P E O P L E A N D C O R A L R E E F S Amajor stumbling block to effective management is the ownership or responsibility of coastal and marine resources. Even informal village level rules are difficult to apply at times. Confusion and uncertainties regarding access to resources or rights, along with low government support often means that poor fishers feel they have little choice but to take what they can, when they can and in any way possible. Indeed they have little incentive to do otherwise. However in areas where conservation has demonstrated that in the longer-term there are enormous benefits from protective management, coastal communities are changing their practices to work towards sustainability. Menai Bay is believed to harbor relatively healthy reefs, but the area is next to centres of high population, and there are increasing indications that serious damage is occurring. The Zanzibar channel, west of Zanzibar, is one of the wider areas of continental shelf and supports a small number of islands, sandy bays and fringing coral reefs. In total there is approximately 90km 2 of coral reef around Zanzibar. The east coast of Zanzibar is home to a human population of 30,000 living within 1 km of mean high water line. There are more than 23,000 fulltime fishers on Zanzibar. The main source of protein on the islands is fish. With these sorts of populations pressure on resources is increasing. Communities are heavily dependent on coral reefs but levels of fishing are increasing and reaching levels where species are depleted and fish and coral communities are damaged or altered. As catch decreases so does income, so poverty in turn increases as does the incidence of destructive harvesting methods. Conservation projects always require the full support of national and local government agencies. They also need the involvement of academia and non governmental organizations working in development. We will increasingly see coastal resources managed by a system of co-management where all stakeholders are involved in the planning and management process with strong emphasis on a communitiy s participation and role. It is a multidisciplinary approach to address many issues that effect resource misuse: political, social, economic and cultural as well as environmental. As coastal communities feel that they have more control over resources and access, they are more likely to become more responsible managers. There is a general move away from the top down government centered approach that rarely involves those coastal peoples who depend on natural resources for their day to day existence. Threats to coral reefs BLEACHED CORAL APPEARS A BEAUTIFUL WHITE COLOUR BUT SOON BECOMES DULL AND GREY IN DEATH. Tropical storms cause vast amounts of damage to shallow water reefs that can take many years to recover from. In exposed reef areas it is common to see the aftermath with broken and overturned coral heads and scattered broken pieces of colonies. The influence of low tides, which means exposure to sunlight and freshwater runoff results in coral death. Increased temperatures which can be exacerbated by low tides can cause coral bleaching and it occurs periodically on a small scale around the world. However, in 1998 the coral reefs of the world suffered the worst bleaching incident ever as a result of climate change. The severe El Niño that year caused water temperatures to rise around the world. Water temperatures hit 31 to 32 C degrees. When water temperatures rise, the zooxanthellae in the coral polyps is expelled. As a result the polyp now has no source of food and so dies. Corals that have been bleached first appear a brilliant snowy white colour. Many visitors on first seeing these white coral s are struck by their beauty and unique-ness. Many of these corals are still living for a time after the zooanthellae has left their tissues. However this wonderful whiteness fades very quickly to a dull grey and is colonized by algae. Such large scale and globally distressing events are of great concern. Perhaps under ordinary circumstances coral reefs can cope with natural disturbances, and given time will recover. But under times of increasing and intense human induced stress any buffering ability available is effectively nullified and coral reefs are finding it increasingly difficult to recover from natural anomalies. C ORALS THROUGHOUT THE I NDIAN O CEAN SUFFERED SEVERE MORTALLY IN 1998 AS A RESULT OF ABNORMALLY HIGH SEA TEMPERATURES RELATED TO THE 1997/98 EL NIÑO 38 39

23 T HE EFFECTS OF A D YNAMITE B L AST C ROWN O F T HORNS STARFISH (Acantha ster plancii) 40 T H R E A T S T O C O R A L R E E F S The Crown Of Thorns starfish (Acanthaster plancii), has often been in the news. Sudden and excessive growth called blooms, first came to the worlds attention in the 1960 s on the Great Barrier Reef in Australia and caused untold damage to reef areas. The species usually occurs in fairly low densities, and is often difficult to see despite its formidable appearance and large size, as it tucks itself away under coral heads or in crevices. At times though, for reasons still unclear, it forms dense aggregations. It feeds by digesting coral tissue, causing large scale damage to reefs and leaves behind bare, dead coral skeletons. Many believe that it is a natural predator of coral reefs and that recent blooms of the species are a result of human interference in the ecosystem such as collecting the only known predators the giant Triton s Trumpet. Dynamite used for quick access to fish can destroy large areas of reef, creating a blast site of 1m diameter or more, turning the reef to desolate rubble. It is also highly unselective killing everything in its path. Both adults and juveniles of all species are killed. And it is wasteful as many of the fish sink to the bottom and are not collected. It is a very lucrative in short term since it is highly efficient, but the over harvest and habitat destruction it leaves behind is impossible to quantify. It takes decades for these reefs to recover and the fisheries that have suffered. Ahighly destructive activity, and one of enormous concern internationally, is coral mining. This is the collection of live coral to use as construction material and its practice is especially prevalent in East Africa. It is a major cause of large scale degradation. Live coral is mined as a cement substitute both locally and commercially. There are two sources of limestone material. One source is from what is termed coral rag which is fossilized limestone and coral around the coastline. Coral rag collection at present causes little damage. The second, and more worrying source is from living coral reefs. Live coral collection causes massive destruction. C ORAL MINED FROM SHALLOW NEAR SHORE AREAS IS PILED ONTO A K ILN OF MANGROVE AND COCONUT WOOD, TO BE BURNED FOR LIME PRODUCTION. T H R E A T S T O C O R A L R E E F S Live corals are usually collected on shallow back reefs at low tide where collectors can wade or dive down to get them. Once taken from the reef, they are then left along the roadway or other drying site before being broken up for aggregate or converted to lime for cement or whitewash. As well as the wholesale destruction of large areas of reef, another concern is that the kilns used to roast the coral to produce lime are fired by mangrove wood. It is estimated that around adult trees are needed to fuel each kiln and these kilns are wasteful as 50% of the coral is unconverted and never used. As populations increase, there will be more demand for building materials and also as tourism increases so do the need for facilities. This is a practice that is unsustainable and alternatives must be found. Alarge number and varieties of fishing gear is in use, from traditional artisanal types to more F ISHING modern commercial gear. Nets called gill nets are the most used gear. Often the mesh is very small and is illegal as it catches all species and juveniles so causing large damage to fish populations. The most physical damage from fishing gear occurs from the use of anchors, smashing corals and dragging along the seabed causing extensive damage on reefs areas. Nets that catch on coral breaking it up and dragging it to the surface also destroying habitat. Hook and line to an extent also causes damage, as lost line becomes entangled on coral and lost hooks attract fish and turtles. In Zanzibar local fishers use the Kigumi fishing method. This involves gill nets being set around a reef area with fishers scaring fish out of coral by using poles to pound the seabed coral. This method is very destructive. The over-harvesting of marine fish and shellfish stock is not just a problem in Zanzibar and the West Indian Ocean, but a global concern. Increasing populations, largely centred at the coast, increases demand for food which in turn increases pressure on coastal resources. Coral reef stock and many marine habitats all over the world are being harvested well beyond what is sustainable. The increases in tourism also contribute as more tourists flock to areas known for their seafood and produce so again increasing pressure. Sewage and pollution is also a concern globally but especially so in poorer countries where access to adequate sewage and waste disposal facilities is minimal. Again coastal populations increase and create more urban sewage and garbage that is dumped untreated into the coastal waters, industrial waste and oil, cause severe damage to ecosystems. Siltation, already mentioned in our section on coastal communities, occurs as a result of deforestation, dredging and seabed mining, smothering habitats and reducing light conditions required by corals, and seagrass habitats. TRAWLERS 41

24 T H E I M P A C T O F T O U R I S M T H E I M P A C T O F T O U R I S M The impact of tourism Wish you were here The population is increasing at 3% a year in Zanzibar with a concomitant increase in tourism as more and more people flock to this island paradise. Coral reefs represent a more recent and lucrative source of income for a growing tourism industry with associated damage. Tourism grew by 22% between 1995 and 1996 with the increase in tourist related structures that are often unplanned. More than 70% of tourists come to Zanzibar for the pristine beaches and to snorkel and dive on coral reefs. However, while the impacts of the dramatic growth in the tourist industry, and therefore the increased number of people diving on coral reefs, must be recognised, the income gained by local communities from increased tourism is vital in the management of these common property resources. Therefore the purpose of this section is in no way meant to discourage tourists from enjoying the beauty of what awaits them underwater, but merely to point out guidelines that should be adhered to for the continued survival and replenishment of life in the Indian Ocean. While the awareness of local communities is being increased to coincide with the devolution of power to local people over the management of these resources, so to must the awareness of tourists of their potential impact of their activities on these resources be incremented. Every year thousands of people are understandably attracted to these aquatic Edens as access improves with the proliferation of dive operators on the island. There are certain areas where tourism can help local communities conserve their marine resources in a sustainable manner. One threat which will become obvious to you as the tourist as you tour the local markets is the abundance of marine curios such as shells, sponges and other living constituents that enrich the diversity of Zanzibar s underwater realm. There is growing concern in this commerce from many environmental pressure groups yet with the absence of any firm guidelines and the continuing success of the trade cannot help but be detrimental. Therefore tourists are encouraged not to partake in the purchase of these items as well as making sure that items are not taken directly from the coral reefs during dive expeditions. These organisms are often taken when they are still living yet even if they are confirmed dead, they still have a role to play in contributing the overall health of the reef. From a coral reef you must take nothing, except some of your most magical memories. Interfering with marine life is also a problem, hitching rides on turtles, scaring pufferfish to defend itself by enlarging its body, all can cause undue stress and in the long term can contribute to a reduction in their ability to stay healthy. It will also have implications on the continued success of tourism in the area as next time they may avoid humans and we will never get to see the wonderful creatures that we came to see in the first place. We must remain solely as observers and must give them the respect that they deserve. Another way to moderate our behaviour would be to avoid careless swimming. By reducing uncontrolled fin kicking and lack of controlled buoyancy we can avoid physically breaking off bits of coral. Coral reefs may resemble colourful lumps of rock but are in no way as hardy and are in fact living organisms and should therefore be treated with the according respect. Contact with coral usually kills the tiny polyps that are the life force of the colony. Damage from this sort of abuse is a major concern worldwide. Areas of the Red Sea in Egypt have been destroyed by the impact of tourism, leaving corals dead and broken. These types of behavioural modifications on the part of the tourist apply just as much to being on the water as they do in the water. As boats drop anchors several times a day on the same reef each time, they smash through the coral and for reefs that regularly undergo this damage, the consequences can be severe. The simple solution is to employ the use of mooring buoys, permanent points at which boats can tie up rather than dropping anchor in random areas, which reduce this form of destruction. While we wholeheartedly encourage visitors to enjoy the splendours that await you underwater, people must be aware that the world of the coral reef is a fragile one and requires care and respect when moving around it if future generations of visitors are to take pleasure in exploring this marine environment. Whilst the threats that we potentially pose seem numerous, there are solutions to all of them through modification of our behaviour that will facilitate the continued success of coral reefs. CORAL REEF CURIOS ARE OFTEN SOLD IN VILLAGES AND TOWNS TO T OURISTS

25 E C O T O U R I S T T I P S O R G A N I Z A T I O N S I N Z A N Z I B A R HIPPOPOTAMUS and WARTHOG TUSKS. REPTILE SKINS such as PYTHON and CROCODILE. ZEBRA and ANTELOPE SKINS and their products. CORAL, GIANT CLAMS and all SHELLS, dead or alive PLANTS including ALOES and some HARDWOODS. All LIVE animals including insects All ELEPHANT IVORY products and other body parts. All RHINO HORN. Coats and other items made from CAT SKINS such as CHEETAH and LEOPARD. SHELLS, JEWELRY and other products from SEA TURTLES and TORTOISES. Some PLANTS such as ORCHIDS and CYCADS. Collection from the WILD of any plant or animal, dead or alive ILLEGAL WILDLIFE TRADE: Are you part of the solution or part of the problem? Tanzania has a wide variety of strikingly beautiful traditional arts and crafts on sale. Many of these skillfully produced items are made from animal and plant parts that are endangered and protected.by getting the proper permits you are supporting the legal and sustainable use of wildlife in Tanzania. This is an important incentive for conservation and contributes to Tanzania s economy and the livelihoods of thousands of people. However, every year, worldwide, thousands of illegal wildlife specimens are confiscated from tourists and other individuals. Ignorance can lead to fines or other legal problems including arrest. ECOTOURIST TIPS Tanzania has strict laws relating to wildlife, fisheries, forestry and CITES, here are some tips to inform you about the laws governing their import, export or other dealings in Tanzania. Documentation is required for all wildlife products leaving Tanzania including plants, mammals, birds, reptiles, amphibians, fish and insects. If you want to take wildlife products home, check whether they are prohibited or regulated. Permits and further advice can be obtained from the Wildlife Division. Only buy from dealers whose licences are publically displayed. Do not rely on assurances of the vendor as to the legality of a souvenir. Check with your home country s embassy and airline on their regulations concerning import and transport of wildlife products. Avoid woodcarvings made from local hard woods, instead choose Mango, Jacaranda or Neem trees. THINK BEFORE YOU BUY. IF IN DOUBT, LEAVE IT. 44 The islands of Zanzibar are massively diverse in the range of habitats and species on them. This richness has not gone unnoticed by the government of Zanzibar or the international community, and several organisations are active on the island with an aim to promote conservation. Some of the major ones include: THE INSTITUTE OF MARINE SCIENCE (IMS) IMS was established by the University of Dar-es-Salaam on the 1st July Their work now covers a range of coastal and marine research from seaweed farming to participating in the United Nations Environmental Programme of the mapping of the East African Coast. IMS s main projects are on the mainland in Mafia and Tanga regions, but investigations have also been carried out into the dolphin populations in the Menai bay area along with many localised projects in the Zanzibar islands. CARE CARE is an international organization that has two main objectives in Zanzibar. Firstly, it raises external funds for conservation issues in Zanzibar, harder than it sounds given the island s turbulent political history. Secondly, it also tries to strengthen the links with the community by forming village management groups. CARE s major project is currently the Jozani - Chwaka Conservation Area, which you can drive through on your way to Menai. CARE hopes to make this and other nearby reserves into a National Park of 5000 ha. and eventually into a United Nations Man and Biosphere Reserve. When visiting Jozani forest, keep your eyes open as the forest holds several rare species of animal. The red colobus monkey is indigenous to the area, and with over 2,500 on the island your chances of seeing one are good. Ader s Duiker are found in only once place on the mainland, Kenya, where only three have been seen in the last ten years (there are between in the Jozani area). Also, there are unconfirmed, reports of the Zanzibar leopard seen in the area. Since there was an extermination scheme in the early 70s, it was believed that they were all extinct. WORLD WILD FUND for NATURE (WWF) WWF came to Tanzania originally as a branch of the central office in Nairobi, before being set up as an independent unit in Since then WWF has been at the forefront of conservation in Tanzania, with projects as wide ranging as community education, endangered rhino conservation and farming techniques development. WWF s flagship project on Zanzibar is the Menai Bay Conservation Area 45 Other organisations in Zanzibar concerned with marine conservation

26 O R G A N I Z A T I O N S I N Z A N Z I B A R O R G A N I Z A T I O N S I N T E R N A T I O N A L Other organisations in Zanzibar concerned with marine conservation 46 GOVERNMENT INSTITUTIONS There are a number of official bodies in Zanzibar that either directly or indirectly play a part or have an interest in conservation and the environment. Some of these include the Department of the Environment, The Commission for Natural Resources and the Commission of Fisheries. All of these Departments play a different role in managing conservation in Zanzibar, be it in the form of rangers patrolling sensitive areas; village education representatives conducting community education programmes or fishery officers checking quotas. CHUMBE ISLAND MARINE PARK Chumbe is a privately (self)-managed marine park situated 8 miles south of Stone Town, and on the northern most edge of the Menai Bay conservation area. It consists of 20 ha. of island, reef and sea. The island itself is about 22 ha. with about 18 ha. forest. Chumbe island itself is steeped in history, with the lighthouse (a relic of British occupation) dating from The park was gazetted by the government of Zanzibar in 1994, an ever since has been run by Sibylle Riedmiller as a private marine protected area and enterprise in ecotourism. riedmiller discovered Chumbe in 1991, and campaigned to have it gazetted. After It was gazetted in 1994 she set up Chumbe Island Coral Park Ltd. to start construction of the bungalows and education centre that occupy a small area by the edge of the forest (the site) today. The 20 minute trip is well worth it. The entire island is run on clean technology with reed filter grey-water beds, solar heating, composting toilets, with zero environmental impact. As for the remarkable coral reef that Chumbe protects, it was described by coral expert, Dr Charlie Veron, from the Australian Institute of Marine Science as the Worlds best shallow-water coral reef. Acknowledgements Thanks go to WWF for the opportunity to write this guide. Also to Winley Sichone for information on Menai Bay, to Toby Roxburgh and James Moir Clark for gathering some of the information used in this book, to Catherine Northing and Sam Clark for solving various endless administrative problems, to Alex Tasker for doing background research, providing drawings and for being an endlessly patient sounding board and sympathetic ear. Thanks are especially due to those who gave their time to review my drafts; Sarah Mills, Alex Tasker, Catherine Northing, Damon Stanwell Smith, Winley Sichone, and most of all Cathy Rosario for editorial advice. Finally thanks goes to all those contributing photographs for use in this guide including Dennis and Sandy Coetzee from the Blue Chip Dive Shop/DSM, Seabreeze, Marleen Steenbergen and Shane Granger IN TANZANIA Department of the Environment PO Box 811, Zanzibar Ministry of Tourism, Natural Resources and Environment PO Box 7227, Dar es Salaam Commission of Natural Resources PO Box 3526, Zanzibar Frontier-Tanzania PO Box 9473, Dar es Salaam Institute of Marine Science (UDSM) PO Box 668, Zanzibar IUCN Tanga and Coastal Zone Conservation and Development Project PO Box 5036,Tanga National Environment Management Council PO Box 63154, Dar es Salaam Tanzania Fisheries Research Institute PO Box 9750, Dar es Salaam The Wildlife Conservation Society of Tanzania PO Box 70919, Dar es Salaam Western Indian Ocean Association (WIOMSA) PO Box 3298, Zanzibar WWF Tanzania Programme Office PO Box 63117,Dar es Salaam Menai Bay Conservation Office Livingstone House, PO Box 774 Zanzibar EUROPE Marine Conservation Society 9 Gloucester Rd, Ross-on-Wye Herefordshire., UK Whale and Dolphin Conservation Society 19 James Street Wes, Bath, Avon, UK World Wide Fund for Nature Panda House, Godalming, Surrey World Conservation Monitoring Centre 219 Huntingdon Rd, Cambridge, UK Coral Cay Conservation 154 Clapham Park Rd, Clapham, London, UK Greenpeace International 176 Keizersgracht 1016 DW, Amsterdam, Netherlands International Society for Reef Studies PO Box 1897, Lawrence, Kansas , USA The Society for Environmental Exploration / Frontier 77 Leonard St, LondonEC 2A 4QS, UK NORTH AMERICA Centre for Marine Education 1725 De Sales Street NW, Washington DC 20036, USA Conservation International 2501 M Street NW. Suite 200, Washington DC 20037, USA International Oceanographic Foundation 4600 Ricken backer Causeway, Box , Miami, Florida Ocean Voice International PO Box 3702, 3332 McCarthy Rd Ottawa, Ontario, Canada AUSTRALASIA Great Barrier Reef Marine Park Authority Flinder St,Townsville, Queensland, Australia Australian Institute of Marine Science Townsville, Queensland, Australia WWF GPO Box 12721, Hong Kong Malayan Nature Society PO Box Kuala Lumpur, 50724, Malaysia KKP (WWF) 23-A Maalindog Street, UP Village Diliman, Quezon City 1101 Philippines Websites providing information and good links to other sites of interest SUGGESTIONS FOR FURTHER READING Allen. G & R. Steene 1994 Indopacific Coral Reef Field Guide. Tropical Reef Research, Singapore.ISBN Gosliner, T., Behrens, D. & Williams, G.C (1995) Coral Reef animals of the Indo Pacific. Sea Challengers inc. California. ISBN Leiske. E & Myers. R (1994) Reef Fishes of the World. Periplus Nature Books. Singapore. Richmond. M (1997) A guide to the Seashores of Eastern Africa and the western Indian Ocean Islands. Pub.SIDA ISBN X. Veron J.E.N Coral of Australia and the Indo Pacific.University of Hawaii Press, USA. ISBN Veron J.E.N (2000) Coral s of the World (3 volumes). Pub. Australian Institute of Marine Science, Townsville, Australia Wilson, R & Wilson. J (1992) Watching Fishes.Pisces Books, Houston,Texas. ISBN Text: Sarah Curran Editor: Cathy Rosario Design & illustrations: Africa Vision, DSM,Tanzania Background research & illustrations: Alex Tasker Photography: Dennis and Sandy Coetzee from the Blue Chip Dive Shop/DSM, Seabreeze, Marleen Steenbergen, Bottlenosed Dolphin/Deba Glockner-Ferrali/WWF-US, Whale/Roberto Zambrano/WWF-US, Marleen Steenbergen, Edward Parker, C. Horrill, AfricaVision and Frontier Tanzania. 47 International organisations concerned with marine conservation

27 D I V E S I T E S Sites to snorkel or dive in Menai Bay Menai Bay has many sites of interest for the snorkeller and diver. Boats can easily be hired to take the visitor to some of the more interesting sites. The islands of Menai are unique volcanic formations. Rising up to form icing cake jagged structures from the often turbulent water of Menai Bay. The years of waves battering them in this exposed bay have given them the appearance of an eaten apple core with the base of the islands eaten away. The coral reefs are interesting in that they are mostly a very thin ring of coral growth in shallow waters close to the land masses. The snorkeller will swim over seaweed and dense seagrass beds before coming to interspersed coral patches and the ring of coral with all its abundance of life. All sites are quite shallow and unfortunately many have suffered heavily from destructive practice and from the bleaching event in A NEMONEFISH S CORPIONFISH 48 49

28 Sites to snorkel or dive in Menai Bay Some suitable sites are given in more detail here and there may be many more areas of interest to visitors. For information on visiting Menai Bay, there are numerous tour operators in Stone Town and local transport to Fumba (where you can take local boats out) or to Kizimkazi, to visit the dolphins. 50 D I V E S I T E S KWALE ISLAND (SAND BANK) A one a half hour boat journey from Kizimkazi, and very close to Fumba, this site can be easily accessed from the sand bank to the north of Kwale island. The site slopes gently from sand and rich seagrass beds to scattered coral bommies. The best coral cover is between 4-10m and is an ideal site for snorkelling. Many PUNGUME Pungume island, the most southerly of the islands in Menai, offers some good snorkelling off the sand bar (1) with a remarkable area of foliose coral. A large area is completely undamaged and in pristine condition. The area stops at around ten meters and is 0 10 Pange Morogo ZANZIBAR Nyange UKOMBE A long two hour trip from Kizimkazi, but around 30 minutes from Fumba, Ukombe reef is a submerged reef area close to Chumbe marine reserve. The reef flat drops off on the western side to around 17 meters. The back reef and crest are good snorkelling sites. Off the reef there are several very good reef drop dives. Large porites coral colonies are here, and the area although effected by bleaching, seems less impacted than other sites in Menai. Visibility is variable along the drop off. A good site for giant clams and reef fish, with large schools of anthias and damsel fish. Butterfly fish are also abundant and diverse in the area. Tele Ndogo Tele Kubwa Mwamba Ukombe varied lifeforms can be found and coral cover is healthy. Fish populations are also good. There is a very high aesthetic appeal with large sand areas and scattered bommies teaming with life. There is a scattered ring of coral growth around the north and west sides of the island worth exploring. The chances of seeing both species of dolphins is high here and divers or snorkellers may hear them clicking underwater. taken over by rich seagrass beds. Further along (2) there are dense seagrass beds with scattered bommies and good fish life making an interesting and enjoyable snorkelling site. At the north east corner of the island is an exceptionally clear site (3). The area is heavily damaged by bleaching and dominated by brown algae, sargassum. However some large porites UKOMBE KWALE ISLAND Fumba Nguruwe (SAND BANK) Ukanga Komonda massive coral forms have survived and fish life is surprisingly good here too. Coupled with the remarkably clear water in excess of 20m, this is a very nice snorkel site. The western side of Pungume is very exposed and not recommended for snorkelling or diving as seas can become very rough quickly. The coral here was hit very badly by bleaching. TINDIJE REEF A half hour boat journey from Kizimkazi Dimbani, The reef starts at 6m sloping gently down to 12m where it becomes sand. Reef runs in an East west direction and probably best done as a drift dive. As there is no sheltering reefs or islands, mooring over the reef can be fairly exposed. The site is good for stingrays and large pelagics. Healthy fish populations, including humphead wrasse and large sweetlips. There are unusual numbers of soldier and squirrelfish along most of the reef. The coral here has however suffered damage. There is some bleaching and a large amount of algal cover although there are areas where coral cover is still quite healthy especially the cascading foliose and plate coral forms on large areas of the crest. A high diversity of sponge formations can be seen at this site. PUNGUME Miwi 2 Unguja Ukuu 1 Nyamembe 3 Uzi TINDIJE REEF Mwamba Mikunga Mwamba Mpya Muungoni Vundwe Mwamba Kobela Muyuni to Paje KIZIMKAZI DIMBANI Menai Bay Conservation Area MBCA KIZIMKAZI DIMBANI Some of the best sites in Menai Bay are those close to the village of Kizimkazi Dimbani where a ring of rich patch reefs, rich in fish life runs around 500m from the smaller bay of the village. UNGUJA ISLAND Border Villages Road Land MBCA Island Kizimkazi Dimbani Jambiani Makunduchi Mtende N W E Mtende mnarani The ring of coral starts at around 7m extending down to around 15m. The area is suitable for snorkelling and shallow dives, and offers some of the best in the area. Large schools of fusiliers, snappers, large sweetlips, surgeons and emperors, as well as large angelfish can be found at this site. Giant grouper and Giant Moray eel were sighted here too. Reefs are dominated by massive coral forms. There are Interesting areas of the solitary coral, (Halomitre pileus), called neptune cap laid out like crazy paving. Healthy plate coral forms can be found here. The soft coral cover is also high. Visibility is very good at around 15m. Turtles can be sighted here as can dolphins. S Mtende border