Why use cryopreservation?

The freezing of sperm is important for several fish species within genetic improvement programmes, in order to diffuse or conserve genetic potential or to evaluate genetic progress.


Cryopreservation of the reproductive products of fish is essential for 4 reasons:

 

• The number of species listed as threatened or endangered is increasing, and the prospects for recovering these species in the near term are diminishing. Cyropreservation can assist in maintaining species and biological diversity.

• Requirements for maintaining captive broodstock and for selecting brood fish from the wild are becoming increasingly stringent, with respect to ensuring genetically representative parents and avoiding adverse effects on wild fish. It is therefore desirable to cryopreserve the genetic reserves available. These reserves can be invaluable in optimising the genetic diversity of the young fish produced by following carefully developed mating strategies, thus enhancing their fitness and prospects for survival in the wild.

• Requirements for maintaining captive broodstock are becoming more complex and necessitate greater space within hatcheries to maintain distinct broodstocks in isolation. It is becoming increasingly advantageous to have genetic reserves on hand in order to reduce the need to maintain live brood fish within hatcheries.

• With increasing knowledge of fish genetics and the ability to genetically engineer fish, it makes good sense to maintain repositories of genetic material that are as diverse as possible, especially since diversity among and within species in the wild continues to decline.

The development of protocols for the cryopreservation of fish embryos would be useful in order to:

 

• Allow the maintenance of large gene pools and reduce inbreeding
• Reduce the pressure on wild populations from collection activities
• Maintain a constant supply of animals
• Decrease aquaculture costs by reducing the facilities needed
• Reduce the impact of aquaculture sites upon wild populations and food resources
• Conserve endangered species

Protocols have been developed for the cryopreservation of sperm for several fish species. Please see the factsheet below for details.

(Information in this section was prepared with the expert assistance of scientist Catherine Labbé).