The Ecological Importance and Ethnobiodiversity of Parrotfishes (Scaridae): A Pacific Island Perspective

Transcription

1 The Ecological Importance and Ethnobiodiversity of Parrotfishes (Scaridae): A Pacific Island Perspective The 11 th Pacific Science Inter-Congress 2 nd 8 th March, 2009 Papeete, Tahiti Session: Biogeography [Ecosystems Session Room 1] Teddy Fong and R. R. Thaman School of Geography, The University of the South Pacific and Asakaia Balawa Waiqanake Village, Vanua Navakavu Rewa Province, Fiji Islands

2 Focus Using parrotfishes (Scaridae) and Vanua Navakavu, Fiji Islands; Bellona, Solomon Islands; Ouvea, New Caledonia; and Tikehau, French Polynesia as a case study, we examine the diversity, ecological niches, conservation status, and the role of parrotfishes as indicator species of the health of our coral reef and nearshore marine ecosystems

3 Ethnobiodiversity A Definition The knowledge, uses, beliefs, management systems, conservation ethics, taxonomies (classification systems) and language that different cultures (including modern scientific and international AID, NGO and development communities) have for BIODIVERSITY

4 The Study Sites Vanua Navakavu, Fiji

5 The Study Sites Bellona, Solomon Islands

6 Global Parrotfish Distribution Europe Asia North America Latitudinal Range Atlantic Ocean Africa Indian Ocean Australia Pacific Ocean Solomons NC Tahiti Fiji South America Latitudinal Range New Zealand ~90 species from 9 genera ~27-28 from 7 or 8 may occur in all study sites except Tahiti 19 from 6 occurs in Tahiti (Bacchet et al. 2006) West to East Indo-Pacific attenuation Map by FishBase

7 Parrotfishes and Phase Names Known to Fishers of Vanua Navakau Species Common Name Initial Phase Terminal Phase ID Bolbometopon muricatum bumphead parrotfish kalia kalia Calotomas carolinus stareye parrotfish ilava vucesa ilava vucesa K,P Calotomas spinidens Raggedtooth parrotfish bubute bubute K Cetoscarus bicolor bicolour parrotfish soqo lawi S,K,P Chlorurus bleekeri Bleeker's parrotfish bubute kakarawa S,K,P Chlorurus frontalis reefcrest parrotfish kakarawa kakarawa K,P Chlorurus japanensis redtail parrotfish soqo (bubute) kakarawa K,P Chlorurus microrhinos steephead parrotfish ulurua ulurua S,K,P Chlorurus sordidus bullethead parrotfish bubute kakarawa S,K,P Hipposcarus longiceps longnose parrotfish ulavi ulavi S,K,P Leptoscarus vaigiensis slender parrotfish bubute? bubute? K,P Scarus altipinnis minifin parrotfish soqo lawi S,K,P Scarus chameleon chameleon parrotfish bubute kakarawa S,K,P Scarus dimidiatus yellowbarred parrotfish maqwa kakarawa S,K,P Scarus festivus festive parrotfish bubute kakarawa Scarus flavipectoralis? yellowfin parrotfish bubute kakarawa S,K Scarus forsteni whitespot parrotfish bubute kakarawa S,K,P Scarus frenatus bridled parrotfish soqo kakarawa S,K,P Scarus ghobban bluebarred parrotfish ulavi lawi S,K,P Scarus globiceps globehead parrotfish bubute kakarawa S,K,P Scarus longipinnis highfin parrotfish kakarawa kakarawa S,K,P Scarus niger swarthy parrotfish soqo soqo S,K,P Scarus oviceps egghead parrotfish maqwa kakarawa S,K,P Scarus psittacus palenose parrotfish bubute kakarawa S,K,P Scarus rivulatus surf parrotfish bubute kakarawa S,K,P Scarus rubroviolaceus ember parrotfish bubute, soqo kakarawa S,K,P Scarus schlegeli Schlegel's parrotfish bubute kakarawa S,K,P Scarus spinus greensnout parrotfish bubute kakarawa S,K,P Note : S = SPC Muaivuso Data recognizes 21 species : Fishermen recognized and had names for 28 species : K = Kulbicki s data recognized 26 species : There are 8 names that distinguish species by colour, : P = We have photographed 24 species : behaviour and morphology

8 Nature of Parrotfishes Belong to the family, SCARIDAE, which is closely related to the wrasse family, LABRIDAE. Well-named based on the fusion of their teeth into parrot-like dental plates and the bright blue-green and ornate coloration of many species (Randall 2005). Most species have a number of distinct growth and color phases ranging from juvenile and sub-adult to the initial adult and terminal male growth phases.

9 Taxonomic History Scarids are one of several recently derived families capable of exploiting reef algae and small colonial invertebrates Acanthuridae, Monacanthidae, Pomacentridae, Blenniidae, Siganidae are others Brucae and Randall (1983 and 1985) created two subfamilies of parrotfishes: Scarinae with 4 genera containing approximately 67 species, and Sparisomatinae with 5 genera and 16 species.

10 Biology The modified pharyngeal apparatus is an important adaptation that has allowed parrotfishes to exploit reef algae and small colonial invertebrates Pharyngeal mill reducing ingested material to a fine slurry (sand) Morphological and meristic characteristics separate species most identifications rely on colour patterns however, most species have at least 3 distinct patterns throughout life (juvenile, IP, and TP) juveniles tend to have a drab mixture of browns, grays and blacks, but as they mature a distinct coloration emerges with the addition of red tones. A third set of colors is donned by males and by females that have recently undergone sex change into males. As these males mature, they exhibit bright, intricate patterns of reds, greens, and blues. but there are some monochromic species fishes that do not exhibit sexual color change many species share common colour patterns especially as IPs (concurs with TEK) colours also change after death accurate identifications for many species is best restricted to the colourful TP stage

11 Bicolor Parrotfish (Cetoscarus ocellatus) Terminal Phase Male Initial Phase Female or Male

12 Reproductive Behaviour Complex socially influenced sexual change (socio-sexual) system Most species are protogynous hermaphrodites (individuals maturing first as females, then sexually transforming into males) This sexual transformation is usually accompanied by a change in colour phase Parrotfishes exhibit several types of complex mating systems that vary more by geographic location than by species Reasons range from population density to competition for spawning sites and other resources to geographic factors like seasons and water temperature.

13 Nature of Parrotfishes There are two main groups of parrotfishes based on their jaw and tooth structure and their impact on coral reefs: EXCAVATORS and SCRAPERS. Some of the larger species feed, in part, on live coral, often leaving a characteristic mark from their dental plates.

14 Nature of Parrotfishes (cont.) The excavators have more powerful jaws and stronger dental plates and are able to remove part of the limestone or coral as they feed. They include members of the monospecific genera, Bolbometopon and Cetoscarus and members of the newly recognized genus, Chlorurus.

15 Excavators (A - Bolbometopon muricatum, B- Cetoscarus ocellatus, C Chlorurus bleekeri, D Chlorurus microrhinus) A C B D

16 Nature of Parrotfishes (cont.) The scrapers have less powerful jaws and ingest less inorganic material with the surface algae. Scrapers (A Hipposcarus longiceps TP, B- Scarus altipinnis TP)

17 Feeding Habits Primarily herbivorous Grazing on dead, algae-coated coral (concurs with TEK) And seagrasses (concurs with TEK) Bumphead parrotfish is the exception Consumes significant amounts of live coral Some species, including juveniles and subadults, feed, in part, on algae growing on compact sand surfaces, taking in sand with the algal food (Randall 2005). Form large feeding groups, sometimes with other species (concurs with TEK) To overwhelm territorial fishes and discourage predators

18 A Keystone Species? Parrotfishes have a major impact on coral reefs through intensive grazing and associated bioerosion. Grazing patterns of large schools of parrotfish prevent algae from choking out corals. Many parrotfishes feed on calcareous algae (algae that are high in mineral calcium) contributing significantly to the process of bioerosion and the creation of sediment on reefs. A single Bolbometapon muricatum (bump-head parrotfish) consumes approximately one cubic meter of coral skeletons per year, and turns it into fine sediment. In this way large schools of bump-head parrotfish determine the fine-scale topography of coral reefs. (Choat and Bellwood, 1998) They consume plant material unavailable to most other fishes making them an ecologically important species The large amounts of parrotfishes on reefs makes them an important part of the predatory food chain. Parrotfishes do not only indicate the health and recovery of fish stocks, but can also be used in indicating the health of reef trophic structures, coral reef status and lagoon sediment budget.

19 Threats to Ethno-biodiversity Whereas modern fishermen and many of today's youth often generalize and give parrotfishes one name, traditional fishermen have names for the juv., IP and TP. Ouvea has only 3 distinctive names for over 20 species Bellona has 7 distinctive names for 27 species Researchers in this field often cover TEK, ethno-biology and sacred sights but fail to cover traditional taxonomy Most surveys are not carried out at the same taxonomic level as that of the traditional fishermen (1000s of years of knowledge). While recordings of TEK can be used in schools and by science it still fails to address the loss of it because kids cannot fathom what s being taught. The challenge is to get the good scientists to work with the local scientists.

20 Bumphead Parrotfish Slaughter! Nabukalou Creek Fish Market, 17 March 2007

21 Facilitating Partnerships/Funders MacArthur Foundation