Cryopreservation of finfish and shellfish gametes and embryos

Advances in research on cryopreservation of gametes and embryos of aquatic organisms are modest compared with work done in terrestrial animals and plants. While sperm has been successfully cryopreserved in a number of cultured finfish and shellfish species, utilization at the farm level is still very limited. Modest success has been achieved in the cryopreservation of shellfish embryos and early larvae. On the other hand, cryopreservation of finfish ova and embryos has not been successful so far. Unlike shellfish eggs and embryos, finfish ova and embryos are large, contain a large amount of yolk and are covered with a relatively thick chorion. Uniformity in the penetration of conventional cryoprotectants and in cooling during the freezing process has not been attained in these large and dense specimens. Just as cryopreservation has many practical applications in breeding terrestrial plants and animals, cryopreservation also offers the same potential in the artificial propagation of many aquatic animals. Furthermore, cryopreservation has a significant role in such concerns as aquatic biodiversity, eco-toxicology, and environmental conservation. This paper reviews the recent advances in finfish and shellfish gamete and embryo cryopreservation. Work done in the authors' country is discussed separately from those in the other countries. Future cryopreservation research in aquatic animals is directed towards overcoming the problems posed by finfish ova and embryos using very recent technical innovations. The wide application of cryopreservation in fish farming and in the preservation of aquatic animals in general is encouraged. (C) 2001 Elsevier Science B.V. All rights reserved.