ABSTRACT
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Cryopreservation of germplasm of aquatic species offers many benefits in the fields of aquaculture, conservation, and biomedicine. It brings the possibility of preserving specific species or strains of particular interests, increasing the representation of genetically valuable animals, extending the reproductive life of a particular animal, and avoiding genetic losses through disease, catastrophe, or transfer between locations. In fish culture and farming, the successful cryopreservation of gametes, eggs, and embryos will offer new commercial possibilities, allowing the unlimited production of fry and potentially more robust and better conditioned fish as required. Further advantages include optimal utilization of hatchery facilities and facilitation of transport of stocks between hatcheries. Germplasm cryopreservation also provides a secure ex situ method for preserving the genomes of endangered species in diversity high enough to reconstruct stable populations when environmental conditions make it possible (see also Chapter 13). More than 65% of the European fish species are threatened (Kirchofer, 1996), and worldwide, the number of species listed as threatened or endangered grows rapidly. The extremely endangered species may be extinct before recolonization is possible, or their genetic variability may be so reduced that reconstruction of a stable population is impossible (Gilpin and Soule, 1986). Fish germplasm is also playing a significant role in human genomic studies. The relatively small size of fish genomes make them easier for sequencing, and ideal models for studies on vertebrate development and human disease. Understanding the relationship between fish and human genomes will help identify roles for human genes from fish mutations and help identify fish models for genes identified by human disease (Barbazuk et al., 2000; Brownlie et al., 1998). Successful cryopreservation of fish germplasm will be of benefit of biomedical as well as embryological and molecular biological studies.
