Some aspects of the fishery, ecology and the reproductive biology of Holothuria Scabra (Jaeger, 1935) along the coast of Dar es Salaam.
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Date
2002
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University of Dar es Salaam
Abstract
More than 10 commercial sea cucumber species were recorded at three landing sites along the coast of Dar es Salaam. The most important were Holothuria scabra, Thelonata ananas, Thelonata anax, Bohadschia vitiensis, Holothuria nobilis, Actinopyga milliaris, Actinopyga mauritiana, Stichopus chloronotus, Stichopus hermanii and Holothuria edulis. Other sea cucumbers of low value are known by their local names as "Ulimbo, Kipilipili, Tambi, Sumu, Shapedi, Kibuta and Maua". H. scabra showed considerably higher abundance in Buyuni compared to Mjimwema and Kunduchi, (Fr = 19.44, P<0.0001). There was significant difference in abundance between the three sites (P<0.001). Investigation on the level of exploitation showed significant difference between all study sites. There were temporal variations of H. scabra abundance at the three sites. The catch was generally high during March, April, July, November and December. H. scabra at Buyuni was found to prefer tidal pools located in sea grasses and algae (Fr = 32.5, P<0.0001). Small gastropods, detritus, debris of red algae and fresh pieces of polychaetes were observed and unidentified animal parts mixed with sediments were noted in the gut content. Length frequency distribution of H. scabra showed dominance of young individuals ranging between 7-16 cm. The multiple comparison of size frequency of H. scabra between Kunduchi and Mjimwema showed significant difference (P > 0.05) while that of Mjimwema and Buyuni was highly significant (P < 0.001). Studies on the reproductive biology of H. scabra showed that the length at first maturity is 16.8 cm and they breed throughout the year with two spawning peaks (August - September and December - January). The statistics from the Fishery Division of Ministry of Natural Resources and Tourism showed some discrepancy with those of FAO and a survey of local markets revealed declining size, quality and quantity in Dar es Salaam. Further studies on ecology of developmental stages and future consideration in the conservation and management for holothurians are recommended.
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Keywords
Fishes ecology, Fishery reproductive biology, Holothuria Scabra, Dar es Salaam Coast, Sea cucumber species
Citation
Mmbaga, T. K. (2002). Some aspects of the fishery, ecology and the reproductive biology of Holothuria Scabra (Jaeger, 1935) along the coast of Dar es Salaam. Masters dissertation, University of Dar es Salaam. Available at (http://41.86.178.3/internetserver3.1.2/search.aspx?formtype=advanced)