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

Abstract

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 ar-ti¢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 À1 ) was the most successful hormone treatment for both species. Pretreatment of ¢sh with Ovaplant (28^68 mg kg À1 , 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.

DNA Barcoding Indonesian freshwater fishes: challenges and prospects

“…are rheophilic species know to migrate downstream during the onset of the raining seasons for spawning [12] and as such have been largely affected by the development of dams. Furthermore, Mahseer's controlled breeding is still poorly developed mainly due to the difficulties to induce maturation and ovulation by using hormonal treatments [126]. The dynamic of migration and life history traits are still poorly known in Indonesian populations of Mahseers from Sumatra and Kalimantan, however, cryptic diversity and population structure among rivers have been regional main town of Cairns, it was recommended to review the protective status for all Sicydiinae gobies of the country as the interest in collecting Stiphodon species is likely to be high for native fish hobbyists [141].…”

Sperm Cryopreservation of Some Freshwater Fish Species in Malaysia

“…The first successful hormonal induction spawning of T. tambroides under captive pondreared environment was reported by Ingram et al (2005). In captive condition, T. tambroides seems to spawn all year round.…”

“…Similar to other indigenous fishes in Malaysia, the wild populations of Malaysian Mahseer are declining over the years as the consequences of over-exploitation, natural habitat degradation and water pollution. Therefore, Malaysian Mahseer is now classified nationally as ecologically threatened (Ingram et al, 2005).…”

GENETIC VARIATION OF Tor tambroides (Bleeker, 1854) ALONG BATANG TARUSAN RIVER, WEST SUMATERA: IMPLICATIONS FOR STOCK IDENTIFICATION

“…These species are largescaled barbells that live in upstream, clear, running waters (Shrestha, 1990;Ng, 2004). They are attractive as sport fish (Ng, 2004), and are of great economical value and conservation concern (Nguyen et al, 2006), as well as of aquaculture potential (Ingram et al, 2005).…”