Induced spawning, larval development and rearing of two indigenous Malaysian mahseer, Tor tambroides and T. douronensis

By B. Ingram, S. Sungan, G. Gooley, S. Sim, David Tinggi, S. S. Silva. 2005

113 citations recorded by the source corpus.

The Mahseers (Tor spp.) are highly valued freshwater ¢shes across the Himalayan and South-east Asian regions. Over exploitation of natural stocks because of high demand and the deteriorating environmental conditions have resulted in marked decline of mahseers in the wild. Malaysian mahseers, T. tambroides (Bleeker) and T. douronensis (Valenciennes), locally known as empurau, kelah or belian and semah, respectively, have signi¢cant cultural and economic importance but both species are now threatened in the wild because of environmental degradation and over ¢shing. A captive breeding programme was instigated to attempt to propagate these two species arti¢cially for conservation and aquaculture purposes. Both pond-reared and tank-held T. tambroides and T. douronensis reached sexual maturity in captivity and were successfully induced to spawn using hormone treatments. Ovaprim (0.5 mL kg � 1 ) was the most successful hormone treatment for both species. Pretreatment of ¢sh with Ovaplant (28^68m gk g � 1 ,2 ^7 weeks before spawning induction) greatly improved the success rate of spawning induction. Repeat spawning (within 4 months of initial spawning) was induced in some captive ¢sh. Use of formalin baths improved hatching by preventing fungal infections. Embryonic development and hatching are described. Juveniles were reared in static greenwater ponds. Tor tambroides reached 142^179 g (max 270 g) in 60 weeks. These results represent the ¢rst successful captive spawning and rearing of both species. Options for future research to improve production are discussed.

Subfields: Aquatic Science, Nature and Landscape Conservation, Physiology

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