REPRODUCTIVE BIOLOGY OF A COMMERCIALLY IMPORTANT SEA CUCUMBER Stichopus horrens IN MALAYSIA: IMPORTANT INSIGHTS FOR AQUACULTURE DEVELOPMENT.

Syed Zulfaqar*, M. Aminur Rahman**, Fatimah Md. Yusoff and A. Arshad
 Laboratory of Marine Biotechnology,
Institute of Bioscience, Universiti Putra Malaysia,
43400 UPM Serdang, Selangor, Malaysia
*Presenting author's E-mail: syedzulfaqarsmk@gmail.com
**Corresponding author's E-mail: aminur1963@gmail.com

Sea cucumber fisheries have seen a period of relative increase in catch in the past decades. The rise in catch has brought together the unintended consequences of overexploitation and resource exhaustion. These circumstances have caused many closures of sea cucumber fishing sites in many parts of the world. Malaysia had also experienced such closure when the sea cucumber fisheries in one of the most famous landing site in Langkawi Island collapsed around mid-1980s. The tragedy has since sparked interest in a national aquaculture program for possible production of sea cucumbers without reliance upon capture fisheries. Despite these positive initiatives, Malaysia is still heavily relied on capture fisheries for sea cucumbers. As such, greater attention for management of these resources is to be demanded. There are however very limited accounts of the biology of sea cucumbers species available in Malaysia. Such knowledge, especially on the reproductive biology of sea cucumber species will not only be good for management of the capture fisheries but might also enhance the prospects of good aquaculture program. In a view to understand the modes of gonadal development and reproductive patterns, we investigated the commercially important sea cucumber, Stichopus horrens for a period of one year. Monthly samples of 20−40 sea cucumbers were collected from Pangkor Island, Perak, Peninsular Malaysia. The samples were dissected and their gonads were analyzed in the laboratory through macroscopic and histological examinations. The gonad weight and tubule diameter were significantly different between male and female, being heavier and longer in the latter. The gonad index (GI) was peaked at 0.76% in September, 2015 and gradually declined to the lowest at 0.03% in May, 2016. The proportion of matured species was also the highest in September, 2015. The spawning started in September, 2015 and prolonged up to April, 2016 with the majority spawned in November, 2015. The results also demonstrated that matured species can be found almost throughout the year. The prolonged release of gametes and availability of matured adults throughout the year might facilitate sustainable aquaculture program of this species. The period of enhanced spawning observed will also contribute to better management of broodstocks in such program to a greater extent.

Key words: Sea cucumber, Stichopus horrens, Reproductive biology, Aquaculture, Malaysia