Sperm Cryopreservation of Some Freshwater Fish Species in Malaysia

Sperm Cryopreservation of Some Freshwater Fish Species in Malaysia 

Ex Situ Conservation Methods

Ex-situ conservation is the preservation of components of biological diversity outside their natural habitats.  This involves conservation of genetic resources, as well as wild and cultivated or species, and draws on a diverse body of techniques and facilities.  Gene banks, e.g. seed banks, sperm and ova banks. 

Cryopreservation of fish semen and considering Malaysia has a rich fish fauna with many of them unique to this tropical region, cryopreservation of fish gametes will require detailed study to create new protocol for each fish species intended for semen cryopreservation. To date in Malaysia semen cryopreservation has only been reported for several freshwater fish species, namely Probarbus jullieni, Tor tambroides, T. deuronensis, Hemibagrus nemurus, Pangasius nasutus, Hypsibarbus wetmorei, Barbonymus gonionotus and Clarias gariepinus. It has been demonstrated that semen cryoperservation plays an important role for the genetic conservation of these fish species. 

Cryopreservation technology for fish semen is still not well explored in Malaysia and can be considered as new if compared to the domesticated terrestrial livestocks. Henceforth, this has opened up a new field to be explored with potential applications in aquaculture and in the conservation of the national fisheries genetic resources. Cryopreserved semen could facilitate artificial fertilization especially when mature male fishes are not available or unable to provide viable semen during certain periods of the breeding season. Semen cryopreservation may also be useful for fertilization to produce hybrids of various fish species. It also helps in reducing the cost and labor of maintaining broodstocks under in situ condition. In line with the mission of Department of Fisheries (DOF) Malaysia to develop and manage the national fisheries sector in a sustainable manner, the gene bank of freshwater fishes in the form of semen cryobank of Fisheries Research Institute at Glami Lemi was established in 2008. The establishment of the semen cryobank research has achieved the aim of the DOF towards establishing a national semen cryobank (gene bank) in Malaysia for conserving the genetic materials of the threatened or endangered indigenous freshwater fish species and also for those indigenous species which has potential for aquaculture.

An overview of the current status of semen cryopreservation of Malaysian freshwater fishes is presented in this chapter. The role of semen cryobank is also discussed. Obviously, semen cryopreservation offers potential applications in ex situ conservation and sustainable management of the fisheries genetic resources in Malaysia, especially for those species with rare, vulnerable, threatened or endangered status, those protandry species with sexchanging characteristic over their life time, and also the potential candidates and genetic improved strains for aquaculture development. The successes in semen cryopreservation are very much relied on factors such as having ample knowledge on the biology and reproductive biology of the particular species of interest, trained personnels in various aspects such as gamete cryopreservation, breeding methods, broodstock management and husbandry and larva rearing and nursing of the targeted species.