Conservation of Atlantic salmon - gene banking: principles and considerations

Introduction to gene banking

Gene banking may be considered as part of a conservation strategy to respond to declines in populations by retaining inherent genetic biodiversity within and across stocks, as well as the associated adaptive capacity to evolve to meet future environmental changes. Such genetic conservation is not an end in itself, but rather a means of ensuring that genetic diversity within and across populations is retained.

There are two basic approaches to conservation strategy: in situ and ex situ. In situ methods maintain stocks in their original habitats, whereas ex situ conservation maintains organisms outside their original habitats in facilities, such as hatcheries and/or preserves frozen gametes or embryos in cryobanks. The approaches are not mutually exclusive: different conservation systems can complement each other and ensure against the shortcomings of any one method (FAO 1993). In principle, ex situ gene banking can be achieved through the maintenance of breeding population/s in a hatchery (Live Gene Banking), and/or the cryopreservation of gametes (Cryobanking/Cryopreservation). Gene banks or cryobanks are thus types of ex situ biorepositories that seek to preserve genetic material. These two approaches are examined in detail below.

Thus, gene banking can be seen to be a potential tool in the arsenal of different conservation options available. However, as with many such interventions, it has inherent risks, which must be addressed. The opportunities and risks are examined in detail below. Furthermore, gene banking is not universally applicable as an appropriate approach to conservation.