TANZANIA MARINE RESEARCH PROGRAMME. Utende, Mafia Island, Tanzania

Transcription

1 TANZANIA MARINE RESEARCH PROGRAMME Utende, Mafia Island, Tanzania TZM Phase 144 Science Report 23 rd September 15 th December 2014 Catherine Gutmann Roberts (Project Manager) 1

2 Staff Members Name Catherine Gutmann Roberts (CGR) Allison Shafer (AS) Jamie Lawson (JL) Louise Howell (LH) Amanda Dennis (AD) Abbalena Sherwood (AS) Position Principal Investigator/Project Manager (PI/PM) Assistant Marine Research Officer (AMRO) Conservation Apprentice (CA) Outgoing Dive Officer (DO) Incoming Dive Officer (DO) Assistant Dive Officer (ADO) Volunteers Name Olivia Lacasse Romany Burns Rhianna Jarvis Danny Heydon Katja van Rennes Leanne Albon Stephen Albon Suzie Fordce Mike Taylor Inge Schringver Programme Marine conservation and diving Marine conservation and diving Whaleshark and Turtles Marine conservation and diving Marine conservation and diving Marine conservation and diving Marine conservation and diving Marine conservation and diving Divemaster Internship Marine conservation and diving 2

3 Contents 1. Introduction Training Briefing Sessions Science Lectures Field Work Training Tropical Habitat Management BTEC Research Work Program Survey Areas Survey Methodology Statistical Analysis Method Overall Results Benthic Analysis Fish Analysis Invertebrate Analysis Discussion Proposed work programme for next phase References Appendices

4 1. Introduction Tropical marine ecosystems, including coral reefs, mangrove forests and seagrass meadows, are valuable environmental resources that provide significant economic goods and ecosystem services to people all around the globe (Kimirei, 2012; Nagelkerken et al., 2000; Hughes et al., 2003). They contribute to the livelihoods and food security of millions of people living in coastal countries and play a crucial role in both stabilizing global ecosystems and in mitigation of coastal erosion (Hoegh-Guldberg, 1999). The health and stability of these resources is therefore critical to human wellbeing worldwide (Wilkinson et al., 2008). Tanzania is currently ranked as one of the world s poorest countries, with a large proportion of its population directly or indirectly depending on coastal ecosystems for the provision of cheap, easily accessible protein through subsistence fishing and trading marine resources, in addition to benefits associated with dive tourism (Francis et al., 1997). Amongst Tanzania s administrative regions, the Mafia Archipelago is one of the least developed, with a disproportionately large percentage of the population depending on farming and subsistence fishing (Holberg, 2008). Mafia Island is located approximately 120 km south of Dar es Salaam, 20 km offshore of the Rufiji Delta and 850 km south of the equator. It is centrally located in the Mafia Archipelago, a sandstone and coral rag chain consisting of 15 islands, several of which are inhabited. Mafia is the largest, measuring approximately 50 km by 15 km, with an estimated population of 40,000 people living on the main island, the majority being based in the south of the island. The archipelago is significantly less developed than neighbouring Pemba and Zanzibar (Holberg, 2008; Boeser, 2005) and receives far fewer tourists per year (Holberg, 2008). However, as foreign investment increases, it has been predicted that this will change over the coming years. While increased tourism and development of infrastructure is expected to benefit the local population, it also puts pressure on a way of life that has been conserved over countless generations. Subsistence fishing and unregulated small scale trade are often the only means of obtaining protein on Mafia Island (Holberg, 2008). Given the fragility of the coastal ecosystems, intensification of these practices may lead to biodiversity loss. The creation of a sustainable fisheries system that guarantees the long term livelihoods of people while also protecting the reefs is therefore of primary concern (ISRS, 2004). A management plan was established for Tanzania s first multi-user marine park, which was gazetted in Marine Protected Area (MPA) designations can range from strict no take zones to communally managed multi-use parks, depending on the desired outcome (Mclanahan, 2006). Multi-use marine parks aim to conserve resources and biodiversity, as well as improving the fisheries and livelihoods of local people. Successful MPAs have increased abundance and biomass of target species (Lester, 2009), raised fish recruitment rates (Evans et al., 2008) and increased migration of adults into neighbouring areas (Jupiter and Egli, 2010). At the 2003 World Parks Conference in Durban, South Africa, Tanzania pledged to dedicate 10% of its marine areas for conservation by 2012, rising to 20% by 2025 (Ruitenbeek, 2005). Tanzania currently has 12.5% of its coastal waters under some form of protection (Ruitenbeek et al., 2005). The marine park boasts high reef biodiversity with 273 species of coral within 63 genera (Obura, 2004). Fish biodiversity is also high, with 394 species recorded from 56 genera (Garpe and Ohman, 2003). The marine habitats around Mafia are some of the richest on the East African coast and the marine park is a critical area for biodiversity (CBD, 2001). It provides nesting habitat for Hawksbill and Green turtles and is a feeding ground for Loggerheads, Olive Ridley and Leatherback turtles (Muir, 2005). As well as having an important coral reef system there are also important seagrass beds around Mafia Island where there are reports of Dugongs that are almost extinct within East Africa (Muir et al., 2003, Marsh, 2008). 4

5 The Mafia Island Marine Park encompasses both terrestrial and marine habitats in its management plan, and has more than 23,000 people living within its boundaries (MPRU, 2011). Fisheries resources provide the majority income for most residents within MIMP focussing on fin-fish, octopus and lobster (MPRU, 2011). Hence, the management needs to finely balance environmental conservation with socio-economic development (MPRU, 2011). The Marine Park is responsible for 822 km of coastline, almost half of the shore around Mafia Island (Fig. 1). While the park management has been partly successful enforcing gear and boat confiscation and taking legal action (Pers observation and communication, 2014), some challenges have arisen including lack of funding for patrolling the park and enforcement of fishing regulations. Within the park, a zoning policy was developed with three zones; Core/No-Take, Specified Use and General Use. Within Core Zones there is no resource extraction but diving and research is permitted; within Specified Use Zones there is no pull net fishing allowed and no fishing by non-residents, and within General Use Zones national fishing regulations apply, with non-residents requiring a permit to undertake activities within the park. As with most protected areas, illegal practices occur and undermine the management in place, there are regularly reports of fishing activity within the Core Zone and even destructive fishing practices that are illegal across Tanzania, are happening in MIMP, such as dynamite fishing and beach seine netting. Figure 1: Management zonation of the MIMP. See figure key for the different zonation areas of the MIMP. Few studies have assessed reef-fish assemblages in Tanzania (McClanahan 1994, McClanahand & Arthur 2001, Garpe & Ohman, 2003) and even less literature is available on interactions between reef health and invertebrates (Fabricius, 2005). There is little data on the efficacy of the current management techniques and the Marine Park does not have the ability to carry out monitoring in the area. The aim of the current project is to implement and complete aspects of a five year survey and monitoring programme agreed between Frontier and the MIMP. Objectives within the programme include but are not limited to: Collection of baseline biodiversity data on coral reefs Collection of baseline mangrove survey data and mapping of habitats Collection of baseline seagrass bed data and mapping of habitats 5

6 Comparison of biodiversity in different use zones Collection of socio-economic survey data on fisheries areas and fishing methods Collection of socio-economic survey data on mangrove harvesting, forest logging and coral mining Collection of socio-economic level data, including poverty, access to health care, education and impact of tourism Collection of socio-economic data on community relations Feasibility studies of potential aquaculture projects Development of a management plan and risk assessment report for the MIMP, based on evaluation of datasets. An important practical indicator of the MIMP success is the health of its fisheries. Maintaining fisheries can provide both indicators of reef community health and livelihoods to local people who depend on the marine resources. MIMP and Frontier have developed a proposal to monitor fisheries in the different management zones of the marine park. Belt transects are used to estimate the diversity and abundance of fish, benthos and invertebrates (Hill et al., 2004). The aim of conducting baseline survey protocols is to provide an assessment of the abundance, species richness and size of commercial fish within Chole Bay, the health of the coral reefs and the species richness of invertebrate indicator species. The hypothesis was that zones with stricter protection would have higher fish and invertebrate abundance and diversity. Higher fish abundance and diversity is expected as less fishing pressure allows diversity and abundance to increase, through protecting adult and juvenile. Diversity often increases in areas where certain fish are not targeted and apex predators are left to keep systems in balance. Invertebrate diversity and abundance is expected to increase as removal of invertebrates will be lower in areas of high protection and the reef will suffer less damage and degradation which will positively impact invertebrate diversity and abundance. 2. Training 2.1 Briefing sessions Research assistants received briefings after deployment (during the first few days of each month) on health and safety, medical issues, TZM project history, phase aims and objectives and general information on life in Utende. 2.2 Science lectures Marine science lectures were conducted to train research assistants (RAs) in the identification of marine families and species of fish and invertebrates. Training in benthic composition was also carried out to teach RAs how to survey hard corals using morphology, instead of taxonomy, this is done to increase data accuracy as taxanomic ID is difficult for non-specialist surveyors. Additional lectures were delivered to develop a broader understanding of marine ecology and conservation and to stress the need for research and accurate identification. The book Coral Reef Fishes, Indo- Pacific and Caribbean by Leiske and Edward (2001) was used as reference during study sessions. RAs come for a varied amount of time and not all RAs were able to see all lectures. 6

7 Table 1. Science lectures conducted during phase 144 by Catherine Gutmann Roberts, Jamie Lawson, Abbalene Sherwood and Allison Shafer Core Science Lectures Introduction to TZM Hazards of the Reef Commercial Territorial Fish Commercial Schooling Fish Extra Science Lectures Fish morphology and ecology Mangroves Seagrass Marine Protected Areas Surveying and Monitoring Methods Fisheries of Mafia Island Benthic composition Invertebrate Identification Angelfish Identification Turtle Conservation Whaleshark Biology Importance of Coral Reefs Surgeonfish Identification Butterflyfish Identification 2.3 Field Work Training Field work training was provided through a series of Power Point lectures and practical underwater sessions. All lectures were given either at camp or in the field. Lectures were given covering all fish families and species needed for surveys; these were split into territorial and schooling fish groups to aid learning. Phase 144 saw continued use of the fish list used in the previous phase. The current Commercial Fish Species List is designed to suit the needs of the MIMP s long-term monitoring program and focuses on commercial fish species, families which are targeted by the local fishing communities and can be indicators of reef health. Fish tests were completed using PowerPoint presentations; RAs were required to reach a 95% pass mark and staff a 100% pass mark before they could take part in surveying. If RAs initially failed to achieve the pass mark, individual study sessions were held and RAs re-tested until the required pass mark was achieved. After passing these photographic fish, invertebrate and benthic tests, underwater sessions were held with staff to further test RAs and ensure consistency between surveyors. Fish size estimation training was carried out by snorkelling on shore and estimating the size of suspended plastic fish on a line. RAs swam 1-2 meters above the fish and estimated their sizes. RAs were tested multiple times until they were able to accurately estimate the size of model fish to within 5cm with a 95% pass rate for 15 sizes of fish. 2.4 Tropical Habitat Management BTEC BTEC s completed: Jamie Lawson Crown of Thorns (4-week) Rhianna Jarvis Whalesharks (4-week) Romany Burns Fire Coral distribution throughout the bay (4-week) Katja van Rennes Seagrass and fish species (10-week) 7

8 3. Research Work Programme 3.1 Survey Areas Chole Bay is a highly tidal and bathymetrically complex inlet and is separated from the ocean by Kinasi Pass and Chole Pass with an average depth of 20 m. The tidal range in the bay is approximately 3 m on a spring tide and 1 m on a neap tide, with a small intertidal area at mean low water. There are several fringing reefs located mostly between 6 18m depth with many sand beds, coastal seagrass and mangroves areas. Survey sites during phase 144 were only located in the Core, Specified and General Use Zone within Chole Bay. Figure 2.Satellite image of Chole Bay and estimated locations of survey sites, showing the Core and Specified Use Zones within the bay, General Use Zone is the area outside of the polygons (Google Earth, 2014) Milimani North (GPS: S E ) An area of sheltered fringing reef, within the Specified Use Zone (Fig. 2), facing inward from the mouth of the bay. Located several hundred metres west of the Kinasi Pass, this site is surrounded by sand and sea grass beds. Milimani contains a coral shelf that gradually drops to around 20m and contains an abundance of foliose, massive and branching coral. Fish diversity is high, with fish species ranging from moustache triggerfish to juvenile groupers, with large schools of soldierfish frequently observed sheltering in the submassive coral. Milimani South (GPS: S E ) Fringing reef that runs perpendicular to Chole Wall, to the west of Kinasi Pass, and borders the channel running from the mouth of the bay inwards, within the Specified Use Zone. This site comprises mostly of foliose, columnar and submassive coral morphologies. Fish are diverse with lots of damsel fish, soldier fish and triggerfish. Chole Wall (GPS: S E ) Chole Wall is about 3m deep and is within the Specified Use Zone, lying 6.1km from Utende. Chole shows high biodiversity within the bay, with high abundances of Acropora formosa, Acropora valida and Montiporaa equituberculata with Scleractinian corals dominating the benthos. There are many Alcyonacea species including 8

9 Anthelia glauca, Cespitularia erecta andxeniidae spp, all in high abundance. The bathymetry of the site comprises a steep shelving wall from 5-14m with a rich and biodiverse reef flat, falling away to a deep water channel filled with sandy rubble. Exposed to fast currents on the tidal ebb and flow, Chole Wall shows a high abundance of both commercial and reef fish species. Utumbei Deep (GPS: S E ) UtumbeiDeep is a continuation of the Kinasi Pass, leading into Milimani South and is the survey site closest to the mouth of Chole Bay. The bathymetry consists of a number of steep-sloped channels with a maximum depth of 24 m. Utumbei is home to a high number of larger fish species, including Napoleon wrasse, rays and groupers. Although Utumbei straddles the border between the Core and Specified Use Zones, TZM is currently using it as a Core Zone survey site due to the inaccessibility of the Dindini site. Usumbiji (GPS: S 075 E 039) Usumbiji is a General Use site located next to the marker bouy for the edge of the Specified Use Zone. It is a patchy reef with some large rock pinacles, reaching a maximum depth of 14.3 m,although the reef comes up to about 5 m. This is the first phase that this site has been surveyed and the variation in depth makes it difficult to do a steady dive profile but with experienced divers it is manageable. Kinasi Pass (GPS: S 075 E 039) Kinasi Pass is in the Core Zone reaching a maximum depth of around 26 m. Few coral formations are found shallower than 20 m, hence experienced divers are needed to carry out a survey at this depth, as air consumption limits dive time. There is a pinacle of rock with high fish abundance, the rest of the site is predominantly rubble with some black corals. This site is at the entrance of the bay so it is very susceptable to strong currents and dives need to be accurately scheduled to avoid a drift dive. Small Rock (GPS: S E ) Reef around the base of a small limestone island creating a wall dive, near the entrance of Chole Bay and within the Core Zone. Westerly side of the site is shallow rising to 4m below the surface and to the East of the site it reaches a maximum depth of around 15m. Can be subject to strong currents. Coral morphologies varied including some delicate structures such as table coral. A few fish species at this site are not observed at any of the other survey sites. 9

10 Table 2. Number of surveys at each site and their designations Designation Deep Shallow Milimani North Specified 5 4 Milimani South Specified 5 2 Chole Reef Specified 4 4 Utumbe Deep Core/ Specified 3 3 Usumbiji General Use 4 4 Small Rock Core Survey methodology Baseline Survey Protocol (BSP) was conducted by a team of three to five individuals, each allocated a certain domain (or possibly two depending on the numbers of volunteers available). Surveyors recorded information on: Territorial fish; Schooling fish; Invertebrates; Benthic Composition and Physical parameters. All surveys were undertaken using Self-Contained Underwater Breathing Apparatus (SCUBA). The protocol was conducted using a 100m tape measure weighted with a 1kg steel dive weight secured to the anterior end of the tape or with a piece of string attached to a rock at the site. Set as an 80m transect, each transect consisted of three 20m sections with a 10m redundant section between them (0-20, and 60-80m). Surveyors swam slightly above the transect recording their allocated taxa within 5m of the transect (2.5m either side) and to 5m above the sea floor creating a 25 metre square box. Survey dives were aborted if the sea state became higher than a 3 on the Beaufort scale, in strong currents, or if any diver s tank pressure reached 70 bar. Transects remained at a relatively constant depth following the reef contour. Communities were assumed to be distinct at different depths so surveys were classified as deep or shallow within sites and for all sites a contour was classified as being deep below 8m. Due to the variation in depth at each site, it was not always possible to carry out surveys at both deep and shallow areas (Table 2) Prior to the dive; the Physical surveyor recorded the date, survey site, number of fishing vessels on the reef, cloud cover (0-8), Beaufort sea state (0-8) and air temperature ( C). Upon descent, the Physical surveyor secured the end of the tape measure and reeled out 80m of line onto the substrate, securing it within coral or rocks to keep it in place in mild currents. The Physical surveyor would record the start and end time of the survey, the maximum depth of the survey, the visibility (estimated in meters) and the water temperature at the bottom ( C). The Schooling fish surveyor would buddy with the Physical surveyor but swim marginally in front to minimize disturbance to fish. The Schooling fish surveyor recorded all teleost species which generally occurred in groups in the water column (see Appendix for families and species). After five minutes, the Territorial fish, Invertebrate and Benthic surveyors began surveying. The Territorial fish surveyor recorded all species observed within the 25m² box but swam in a generally straight line unless there was an overhang to check underneath. The Invertebrate surveyor swam 2.5m on each side of transect and thoroughly searched for all invertebrates and recorded any they observed (see Appendix). The Benthic surveyor scrutinized the benthos directly below the survey line and recorded the structure (Table 3) and length occupied of any morphology change greater than 10 cm, recorded to the closest cm on the tape measure. The benthic survey methodology has been developed by Frontier and used to collect data at a number of locations, both across Tanzania and globally (English et al., 1987). 10

11 Due to the non-specialist nature of TZM s volunteer surveyors, hard coral species or genus is not recorded. Instead, morphology is focussed on rather than taxonomy, allowing investigation into the function of the reef as a habitat. Coral species have different morphological characteristics as well as morphologies altering with life cycle. All hard coral were assumed to be hermatypic and all soft corals (determined by movement in the water) were ahermatypic (Marshall, 1996). During surveys 8 42, Fire Coral (Millepora spp.) and True hard coral were recorded separately. Both Schooling and Territorial fish surveyors noted the numbers of fish seen and estimated size using distinct categories (0 10 cm, cm, cm cm and 71cm +). If volunteer numbers were low then the groups would be limited to Schooling, Physical, Territorial fish surveyors in that order on the outward transect and then Invertebrate, Benthic and Physical would survey on the return transect. 3.3 Statistical Analysis Method Data was analysed by calculating the Shannon-Wiener diversity index (H) using natural logs of fish species and families and invertebrates, as shown in the Appendix. Fish species and families were rated using the SACFOR (Super Abundant, Abundance, Common, Frequent, Occasional and Rare) scale from quantitative data to determine rare species within the bay. A log scale was used to create categories between the number of surveys 0 1, 2 3, 4 6, 7 12, and (44 surveys with Territorial data and 45 with Schooling fish data). Fish size data was analysed by assuming the median value for a size range (e.g. 15 cm for cm) and then calculating mean fish size for each species within a transect. Only territorial fish which were classed as Super Abundant and Abundant were analysed in this report, due to restricted time frames and to have enough data points to analyse effectively. Statistics were carried out in R-Studio and ANOVAs were used to analyse variable between sites and zones. 3.4 Overall Results Surveyed maximum depths varied from 4.0 m to 14.9 m, hard coral live cover ranged from 1% to 83% with an average of 26% across Chole Bay. Fire Coral (Millepora spp.) ranged from 0 34% with a mean of 13% across Chole Bay. Dead coral and rubble ranged from 1% to 63% averaging at 22% across the Bay. The mean number of fish observed per transect on a survey (fish abundance) ranged from 40 to 1705 individuals. Invertebrate abundance varied between 13 and 330 individuals Benthic Analysis Coral Rubble was amongst the top three most common substrates at all sites apart from Milimani South Deep where it was 7 th and dead coral was among the top ten for all sites apart from Usumbiji Deep (Table 3 & 4). Bleached coral was only among the most common substrates at Utumbe Shallow. Algae was not within the top ten most common substrates for any of the deep survey sites and was only in the top ten at two of the shallow sites (Utumbe and Usumbiji, Table 3 & 4). Massive coral colonies were not in the top ten most abundant substrates at any site. Fire Coral (Millepora spp.) was in the top ten abundant substrates for all sites in the Deep areas and most of the Shallow (except for Milimani North and Small Rock). 11

12 Table 3. Mean percent, Standard Error (SE) and rank of the 10 most abundant substrate categories from Small Rock, Utumbe and Usumbiji, deep (D) and shallow (S) surveys. Massive is omitted from the list, as it was not in the top 10 for any site. Branching to Tabular are true hard coral morphologies. Small Rock D Small Rock S Utumbe Deep D Utumbe Deep Usumbiji D Usumbiji S S Substrate Mean±SE Rank Mean±SE Rank Mean±SE Rank Mean±SE Rank Mean±SE Rank Mean±SE Rank Algae Seagrass Soft Coral Other Sponge Bleached Coral Dead Coral Rubble Rock Sand Branching Columnar Digitate Encrusting Foliose Laminar Submassive Solitary Tabular Fire Coral

13 Table 4. Mean percent, Standard Error (SE) and rank of the 10 most abundant substrate categories from Chole Reef, Milimani South and Milimani North, deep (D) and shallow (S) surveys. Massive is omitted from the list, as it was not in the top 10 for any site. Branching to Tabular are true hard coral morphologies. Chole Reef D Chole Reef S Milimani North D Milimani Milimani Milimani North S South D South S Substrate Mean±SE Rank Mean±SE Rank Mean±SE Rank Mean±SE Rank Mean±SE Rank Mean±SE Rank Algae Seagrass Soft Coral Other Sponge Bleached Coral Dead Coral Rubble Rock Sand Branching Columnar Digitate Encrusting Foliose Laminar Submassive Solitary Tabular Fire Coral

14 Mean amount of substrate Mean amount of substrate TZM 144 Science Report Chole Reef Milimani North Milimani South Small Rock Utumbe Deep Usumbiji Figure 3. Mean amounts of Rubble and Dead Coral (Blue) and Bleached Coral (Red) across all survey sites over 20 m at Deep and Shallow areas showing Standard Error bars Chole Reef Milimani North Milimani South Small Rock Utumbe Deep Usumbiji Figure 4. Mean amounts True Hard Corals (Blue) and Fire Coral (Red) across all survey sites over 20 m at Deep and Shallow areas showing Standard Error bars Dead coral and coral rubble appeared to be in similar amounts at most survey sites, Milimani South and Usumbiji showed the lowest amounts (Fig. 3). Highest amounts of rubble were found at Chole Reef with 23% and 21% at deep and shallow respectively (Table 4). Bleached coral was only surveyed in negligible amounts apart from small amounts at Utumbe Shallow and Usumbiji Deep (Fig. 3). True hard coral was more abundant that Fire coral at all sites apart from Chole Reef Shallow and both Utumbe sites. (Fig. 4). True Hard Coral abundance was highest at Milimani South and Milimani North, two 14

15 Specified Use Zones and actually lowest in the two Core Zone sites Utumbe and Small Rock. Fire coral was most abundant at Utumbe Deep and Chole Reef with least at Usumbiji and Small Rock. Deeper areas within the same site tended to have higher hard coral abundance than shallow areas except for the opposite was found at Small Rock (Fig. 4). Figure 5. Bleached coral cover boxplots at A) sites; Chole Reef, Milimani North, Milimani South, Small Rock, Usumbiji and Utumbe Deep and B) Zones; Core, General and Specified Bleached coral cover was significantly different between sites by ANOVA (F = 8.325, P = 0.003) with the most being surveyed at Utumbe Deep (Fig. 5A). Bleached coral cover was also significantly different between zones with ANOVA (F = 3.008, P = 0.09) with the largest cover in Core Zones (Fig. 5.B). Figure 6. Hard corals cover at A) sites; Chole Reef, Milimani North, Milimani South, Small Rock, Usumbiji and Utumbe Deep and B) Zones; Core, General and Specified Hard coral cover was significantly different between sites by ANOVA (F = 7.248, P < 0.001) with the most being surveyed at Milimani South (Fig. 6A). Hard coral cover was also significantly different between zones with ANOVA (F = 4.126, P = 0.023) with the largest cover in Specified Use Zones (Fig. 6.B). 15

16 Figure 7. Submassive coral cover at A) Sites; Chole Reef, Milimani North, Milimani South, Small Rock, Usumbiji and Utumbe Deep and B) Zones; Core, General and Specified Submassive coral cover was significantly different between sites with ANOVA (F = 3.722, P = 0.005), with Milimani South having the highest cover (Fig 7. A). Submassive coral cover also varied significantly between zones (F = 2.817, P = 0.071) and was highest in the Specified Use Zone (Fig. 7.B). Figure 8. Sand benthic cover at A) sites; Chole Reef, Milimani North, Milimani South, Small Rock, Usumbiji and Utumbe Deep and B) Zones; Core, General and Specified Sand cover was significantly different between sites by ANOVA (F = 3.847, P = 0.004) with the most being surveyed at Usumbiji (Fig. 8A). Sand cover was also significantly different between zones with ANOVA (F = 7.889, P = 0.001) with the largest cover in General Use Zones (Fig. 8.B). 16

17 Figure 9. Mean cover of benthic types at different sites within Chole Bay A) Foliose Coral and B) Rock at Chole Reef, Milimani North, Milimani South, Small Rock, Usumbiji and Utumbe Deep Foliose coral cover was significantly different between sites with ANOVA (F = 2.185, P = 0.069) (Fig. 9.A), with the most found at Milimani South. There was no significant difference in foliose coral cover between zones. Rock benthic cover varied significantly between sites with ANOVA (F = 2.182, P = 0.07) with the most being found at Small Rock (Fig 9. B). There was no significant difference of rock cover between zones. Figure 10. Mean cover of fire coral at different sites within Chole Bay: Chole Reef, Milimani North, Milimani South, Small Rock, Usumbiji and Utumbe Deep Fire coral cover was significantly different between sites with ANOVA (F = 6.195, P < 0.001) (Fig. 10.A), with the most found at Utumbe Deep. There was no significant difference in fire coral cover between zones. 17

18 Figure 11. Mean cover of benthic types at different zones within Chole Bay A) Soft Coral and B) Solitary Coral at Core, General, and Specified Use Zones. Soft coral cover was significantly different between zones with ANOVA (F = 3.282, P = 0.048) (Fig. 11.A), with the most found in General Use zones. There was no significant difference in soft coral cover between sites. Solitary coral benthic cover varied significantly between zones with ANOVA (F = 3.177, P = 0.053) (Fig 11. B). There was no significant difference of solitary coral cover between zones. Figure 12. Mean cover of other substrate types at different zones within Chole Bay: Core, General, and Specified Use Other substrate cover was significantly different between sites with ANOVA (F = 3.367, P = 0.045) (Fig. 12.A), with the most found in General Use zones. There was no significant difference in other substrate cover between zones. 3.6 Fish Analysis Most sites did not exhibit any difference in fish abundance between deep and shallow sites, apart from at Small Rock, where mean fish abundance was three times higher at the shallow site (Fig. 13). Fish diversity was similar between deep and shallow areas of a survey sites Utumbe, Usumbiji and Chole Reef. At Small Rock diversity was greater at the deep site in comparison to the shallow site and at Milimani North the 18

19 deeper site was also more diverse with regards to fish life (Fig. 13). Milimani South, however, had higher fish diversity at the shallower site. Small Rock Deep had lower fish abundance than all Deep Specified Use sites; Milimani North, Milimani South and Chole Reef. Milimani South Deep exhibited higher fish abundance (849 individuals) than Milimani North Deep but most other sites were similar in the deep areas (Fig. 13). Of the shallow sites Milimani North and Small Rock had highest fish abundance (Fig. 13). Fish diversity did not vary greatly between shallow areas (Fig. 13). Fish diversity at Deep sites was highest at Small Rock and Milimani North and Milimani South and Usumbiji (Fig. 13). 19

20 D S D S D S D S D S D S Mean Fish Abundance Mean Fish Diversity TZM 144 Science Report Figure 13. Mean Fish abundance (Red line, Primary axis) and mean Fish diversity (Blue, Secondary axis, Shannon Index H ) ± SE across 6 sites at deep and shallow areas Small Rock Small Rock Utumbe Deep Utumbe Usumbiji Usumbiji Chole Deep Reef Chole Reef Milimani North Milimani North Milimani Milimani South South 20

21 Water temperature ( C ) Fish diversity Mean Fish Diversity TZM 144 Science Report y = -0.29x R² = Water temperature ( C) Figure 14. Correlation between water temperature ( C) per survey and mean fish diversity per survey There is a relatively strong negative correlation between water temperature and mean fish diversity per survey Survey number 0. Figure 15. Water temperature ( C, Blue) and fish diversity (Shannon Weiner diversity index H, Red) across the surveys done in chronological order 21

22 Fish diversity appears to reflect small changes in water temperature with an increase between 26 degrees and 27 degrees showing an increase in fish diversity, however, above 28 degrees there seems to be a shift where fish diversity decreases substantially. (Fig. 15). During phase 144 water temperature ranged from 26 degrees to 30 degrees. 22

23 H G F E D C B A

24 Mean fish abundance per survey TZM 144 Science Report Figure 16. Mean fish size per survey A. Blackspotted Sweetlips, B. Peacock Grouper, C. Coral Hind Grouper, D. Halfmoon Triggerfish, E. Orangestripe Triggerfish, F. Butterflyfish, G. Angelfish and H. Damselfish. Red line shows the average for each zone Core, Specified Use and then General. Blackspotted sweetlips mean size varies between survey sites from 9 45 cm, Core Zones appear to have slightly larger individuals than Specified and General Use Zone individuals appear to be smallest. Peacock groupers size varies between survey sites from cm, where the largest fish are in Core and the smallest are in Specified Use. Coral Hind grouper size varies between survey sites from cm with the largest individuals being surveyed in the Core zone and the smallest in the General Use zone. Half moon trigger fish vary from 5 25 cm between surveys with the largest being found in the General Use zone and the smallest within the Specified Use zones. Orangestripe triggerfish vary from 5 25 cm between surveys with little variation between zones but Core showing marginally smaller and General Use having marginally larger. Butterfly fish, as a family, mean size varied between 5 and 16 cm between surveys, with the largest individuals generally found in the General Use and the Smallest generally found in Specified Use zones. Angelfish, as a family, varied between 5 and 25 cm, with the largest individuals being found in the Core zone and the smallest in the Specified Use zones. Damselfish, as a family, varied between 5 and 11 cm with little variation between different zones y = x R² = Mean invertebrate abundance per survey Figure 17. A) Mean Invertebrate abundance against mean fish abundance per site with a linear trend line There was a very weak correlation between fish abundance and invertebrate abundance (R 2 = , n = 45, Fig. 17). There was a relatively strong positive correlation between Invertebrate diversity and Fish diversity (Fig 18). 24

25 Mean Fish Diversity TZM 144 Science Report y = x R² = Mean invertebrate diversity Figure 18. Mean Invertebrate diversity (Shannon Index H ) and mean fish diversity (Shannon Index H ) per survey. Figure. 19. Fish Shannon diversity between sites within Chole Bay; Chole Reef, Milimani North, Milimani South, Small Rock, Usumbiji and Utumbe Deep. Fish Shannon diversity was significantly different between sites (F = 2.051, P = 0.082), with Utumbe Deep showing the highest diversity and Milimani South having the lowest (Fig. 19). Total abundance was not significantly different between sites or zones. 25

26 Figure 20. Mean number of Moorish Idols at A) Sites; Chole Reef, Milimani North, Milimani South, Small Rock, Usumbiji and Utumbe Deep and B) Zones; Core, General and Specified Sites within Chole bay had significantly different amounts of Moorish idols by ANOVA (F = 2.98, P =0.018) and also between zones (F = 4.95, P = 0.012). Core zones had the highest numbers of Moorish Idols, with General having the least (Fig. 20B) and Small Rock had the most within the sites and Usumbiji and Utumbe Deep had the least. Figure 21. Mean number of Yellowspot Emperor at A) Sites; Chole Reef, Milimani North, Milimani South, Small Rock, Usumbiji and Utumbe Deep and B) Zones; Core, General and Specified Yellowspot emperor abundance was significantly different between sites with ANOVA (F = 2.846, P = 0.022), with Small Rock having the highest abundance (Fig 21. A). Yellowspot emperor abundance also varied significantly between zones (F = 2.962, P = 0.063) and was highest in the Core Zone (Fig. 21.B). 26

27 Figure 22. Mean number of Moustache triggerfish at A) Sites; Chole Reef, Milimani North, Milimani South, Small Rock, Usumbiji and Utumbe Deep and B) Zones; Core, General and Specified Moustache triggerfish abundance was significantly different between sites with ANOVA (F = 2.789, P = 0.024), with Small Rock and Utumbe Deep having the highest abundance (Fig 22. A). Moustache triggerfish abundance also varied significantly between zones (F = 6.123, P = 0.005) and was highest in the Core Zone (Fig. 22.B). Figure 23. Mean abundance of snappers at different sites within Chole Bay A) Paddletail Snapper and B) Blackspot Snapper at Chole Reef, Milimani North, Milimani South, Small Rock, Usumbiji and Utumbe Deep Paddletail Snapper abundance was significantly different between sites with ANOVA (F = 2.041, P = 0.085) with Small Rock having the highest (Fig. 23.A). There was no significant difference in Paddletail snapper abundance between Zones. Number of Blackspot snappers varied significantly between sites with ANOVA (F = 2.581, P = 0.034) with the most being found at Milimani South (Fig 23. B). There was no significant difference of abundance of Blackspot snapper between zones. 27

28 Figure 24. Mean abundance of fish families at different sites within Chole Bay A) Surgeonfish and B) Parrotfish at Chole Reef, Milimani North, Milimani South, Small Rock, Usumbiji and Utumbe Deep Surgeonfish abundance was significantly different between sites with ANOVA (F = 2.119, P = 0.074) (Fig. 24.A). There was no significant difference in surgeonfish abundance between Zones. Number of parrotfish varied significantly between between sites with ANOVA (F = 2.247, P = 0.06) with the most being found at Milimani North and Small Rock (Fig 24. B). There was no significant difference in numbers of parrotfish between zones. Figure 25. Wrasse abundance boxplots at A) sites; Chole Reef, Milimani North, Milimani South, Small Rock, Usumbiji and Utumbe Deep and B) Zones; Core, General and Specified Wrasse abundance was significantly different between sites by ANOVA (F = 2.191, P = 0.066) with the most being surveyed at Small Rock and Utumbe Deep (Fig. 25A). Wrasse abundance was also significantly different between zones with ANOVA (F = 6.611, P = 0.003) with the highest abundance in Core Zones (Fig. 25.B). 28

29 Figure 26. Trevally abundance boxplots at A) sites; Chole Reef, Milimani North, Milimani South, Small Rock, Usumbiji and Utumbe Deep and B) Zones; Core, General and Specified Trevally abundance was significantly different between sites by ANOVA (F = 3.813, P = 0.005) with the most being surveyed at Utumbe Deep (Fig. 26A). Trevally abundance was also significantly different between zones with ANOVA (F = 5.008, P = 0.011) with the highest abundance in Core Zones (Fig. 26.B). Figure 27. Mean abundance of fish species at different use zones within Chole Bay A) Onespot snapper and B) Arabian Spinecheek at Core, General and Specified Zones Onespot snapper abundance was significantly different between zones with ANOVA (F = 3.189, P = 0.052) (Fig. 27.A), with the most abundance in General Use zones. There was no significant difference in onespot snapper abundance between sites. Number of Arabian spinecheek varied significantly between between zones with ANOVA (F = 3.713, P = 0.033) with the most being found in General Use zones (Fig 27. B). There was no significant difference of numbers of Arabian spinecheek between sites. 29

30 Figure 28. Mean abundance of Sweetlip fish species at different use zones within Chole Bay A) Black Sweetlips and B) Whitebarred Sweetlips at Core, General and Specified Zones Black Sweetlip abundance was significantly different between zones with ANOVA (F = 5.161, P = 0.01) (Fig. 28.A), with the most abundance in General Use zones. There was no significant difference in Black sweetlips abundance between sites. Number of Whitebarred sweetlips varied significantly between zones with ANOVA (F = 2.631, P = 0.084) with the most being found in General Use zones (Fig 28. B). There was no significant difference of numbers of Whitebarred sweetlips between sites. Figure 29. Halfmoon triggerfish abundance across Zones Halfmoon triggerfish abundance varied significantly between zones (F = 2.849, P = 0.07) with the highest abundance at General Use zone (Fig. 29). 3.7 Invertebrate Analysis Across all sites, sponges, brittlestars, segmented worms and bivalves were the most common invertebrate with being found at 100, 78, 82 and 84% of surveys. Mean numbers of invertebrates across all surveys showed sponges, 30

31 Mean Invertebrate abundance Mean Inverdebrate Diversity TZM 144 Science Report brittlestars and non-diadema sea urchins as most abundant with 21, 15 and 23 individuals respectively Small Rock Utumbe Deep Usumbiji Chole Reef Milimani North Milimani South 0.0 Figure 30. Mean Invertebrate abundance (Red line, Primary axis) and mean Invertebrate diversity (Blue bars, Secondary axis, Shannon Index H ) ± SE across 6 sites at deep and shallow areas Small rock exhibited the highest invertebrate abundance at both deep and shallow areas, with 173 and 116 respectively, however it showed one of the lowest invertebrate diversities along with Usumbiji Shallow and Milimani South Deep (Fig. 30). There was little difference between deep and shallow areas of the same site with regards to invertebrate abundance, apart from at Usumbiji where the shallower site was twice as diverse as the deeper area (Fig. 30). Invertebrate diversity did not appear to be affected by depth (Fig. 30). Amongst all of the Deep surveys Small rock and Milimani South showed the least invertebrate diversity and Utumbe Deep was the most diverse. Amongst the shallow surveys Small Rock and Usumbiji showed the least diversity and the other sites were all similarly diverse (Fig. 30). Figure 31. A Boxplots of mean Invertebrate Shannon diversity per survey site, B Total invertebrate abundance for each zone 31

32 Utumbe Deep had the highest diversity of invertebrates with Small Rock displaying the least (Fig. 31.A). Total abundance of invertebrates was significantly different between zones (ANOVA; F = 7.513, P = 0.002), Specified Use and General use had similar abundance with Core Zone having the highest (Fig. 31.B). Figure 32. Mean number of anemones at A) Sites; Chole Reef, Milimani North, Milimani South, Small Rock, Usumbiji and Utumbe Deep and B) Zones; Core, General and Specified Sites within Chole bay had significantly different amounts of anemones by ANOVA (F = 88.73, P < 0.001) and also between zones (F = 2.78, P = 0.073). Core zones had the highest numbers of anemones, with Specified having the least (Fig. 32B) and Small Rock and Utumbe Deep had the most within the sites and Milimani North and Chole Reef had the least. Figure 33. Mean abundance of invertebrates at different sites within Chole Bay A) Crown of Thorns and B) Shrimp at Chole Reef, Milimani North, Milimani South, Small Rock, Usumbiji and Utumbe Deep Crown of Thorn sea star abundance was significantly different between sites with ANOVA (F = 2.972, P = 0.017) with Usumbiji having the most (Fig. 33.A). There was no significant difference between Crown of Thorns between Zones. Number of shrimp varied significantly between between sites with ANOVA (F = 2.140, P = 0.125) with the most being found at Chole Reef (Fig 33. B). There was no significant difference of numbers of shrimp between zones. 32

33 Figure 34. Mean invertebrates between different Zones; Core, General and Specified with A) Sea Cucumbers and B) Feather Stars Sea cucumber abundance was significantly different between zones within Chole Bay by ANOVA (F = 3.745, P = 0.032), with Core zone having the highest abundance (Fig. 34 A). Sea cucumber abundance was not significantly different between sites. Feather star abundance was significantly different between zones with ANOVA (F = 2.662, P = 0.081), abundance was greatest in the Core zone and least at the General Use Zone (Fig. 34 B). Feather star abundance was not significantly different between sites. Figure 35. Nudibranch abundance boxplots at A) sites; Chole Reef, Milimani North, Milimani South, Small Rock, Usumbiji and Utumbe Deep and B) Zones; Core, General and Specified Nudibranch abundance was significantly different between sites by ANOVA (F = 2.138, P = 0.071) with the most being surveyed at Milimani South and Chole Reef (Fig. 35 A). Nudibranch abundance was also significantly different between zones with ANOVA (F = 3.400, P = 0.043) with the highest abundance in Specified Use Zones (Fig. 35.B). 33

34 Figure 36. Octopus abundance between A) Sites and B) Zones within Chole Bay Octopus abundance was significantly different between sites with ANOVA (F = 2.617, P = 0.031), with Small Rock having the highest abundance (Fig 36. A). Octopus abundance also varied significantly between zones (F = 2.729, P = 0.077) which was highest in the Core Zone (Fig. 36.B). Figure 37. Sponge abundance between A) Sites and B) Zones Sponges varied significantly between sites with ANOVA (F = 3.509, P = 0.007), Small Rock and Usumbiji had the highest abundance and Utumbe Deep and Chole Reef had the lowest (Fig. 37 A). Sponges also varied significantly between zones (F = 3.080, P = 0.056) with Core having the highest abundance and Specified having the lowest (Fig. 37.B). 34

35 Figure 38. Tiger cowrie abundance between A) Sites and B) Zones Tiger Cowrie abundance varied significantly between site with ANOVA (F = 2.230, P = 0.060), and abundance was highest at Usumbiji (Fig. 38.A). It also varied significantly between Zone with ANOVA (F = 7.142, P = 0.002) and was highest at the General Use Zone (Fig. 38. B). Figure 39. Abundance of sea urchins (non-diadema) between A) Sites and B) Zones Non-diadema sea urchin abundance varied significantly between sites with ANOVA (F = 4.114, P = 0.003), and abundance was highest at Small Rock and Utumbe Deep (Fig. 39 A). Non-diadema sea urchin abundance also varied significantly between Zones by ANOVA (F = 6.252, P = 0.004) with Core having the most and General having the least (Fig. 39.B) 35

36 Figure 40. Segmented worm abundance across Zones Segmented worm abundance varied significantly between zones (F = 2.609, P = 0.085) with the highest abundance at General Use zone and the lowest at the Core Zone (Fig. 40). Zones Figure 41.A shows that the highest number of fishing boats are sited within the Core Zone and Specified use zone, with an average of 2 per survey and the least are seen in the General Use Zone, with an average of 1 per day. Invertebrate diversity (Shannon Index H) was highest within the Specified Use Zone, with an average value of 2.6, slightly lower in the Core Zone at 2.0 and lowest within the General Use zone with an average value of 0.7 (Fig. 41B). Invertebrate abundance was highest within the Core Zone with an average of 133, lower at Specified use with 62 individuals and lowest within the General Use Zone with 21 individuals (Fig.41C). Number of species of Invertebrates found within zones was lowest at the Core Zone with an average of 17 species or family groups and lowest within the General Use Zone with an average of 6 (Fig. 41. D). Shannon diversity index of fish species was highest within the Specified Use (2.4) and slightly lower in the Core Zone with an average value of 2.1 and the General Use Zone had the lowest with an average value of 0.6 (Fig. 41. E). Fish abundance was highest at the Specified Use Zone with 908 fish seen, Core Zone was lower with 655 and General Use had the least with 239 (Fig. 41. F). 36

37 A 0. B C 0. D Core Specified General E 0. Core Specified General F Figure. 41. Showing the difference between the zones in Chole Bay with A. Number of boats seen whilst surveying, B. Shannon Diversity Index of Invertebrates, C. Abundance of all Invertebrate individuals, D. Number of Invertebrate Species, E. Shannon Diversity Index of Fish Species and F. Abundance of Fish 37