Science Advisory Report 2008/027

Evaluation of Captive Breeding Facilities in the Context of their Contribution to Conservation of Biodiversity

Summary

• Live gene banking programs are not a stand-alone solution to conservation of biodiversity. Threats to a wild population must be addressed effectively for the conservation of biodiversity to be achieved.
• The conclusions below were developed specifically for programs designed for severely depleted populations where there is thought to be a serious risk of extirpation. Guidelines for use of facilities in other circumstances already exist and were endorsed.
• Maintaining genetic diversity in a captive breeding program during a period of very low survival in the wild is a wise strategy whenever the low survival is due to a cause which can be addressed by management intervention, and such interventions are planned or possible to implement; or the low survival is due to environmental causes and there is an expectation that in the future conditions may return to those associated with higher survivorship. Other conditions are discussed for when captive breeding program may also be appropriate strategies.
• With careful attention to a number of aspects of the breeding program at least neutral genetic diversity within populations (and perhaps quantitative genetic diversity) can be sufficiently maintained in captivity for several generations, with loss rates estimated to be below 2% per generation. This rate is much lower than expected loss rates without attention to those aspects of the breeding program.
• Nine specific practices are listed that should be part of captive breeding programs to minimize loss of genetic diversity. These include practices applied in selecting founders, developing mating strategies, managing family sizes of progeny, protection against failures of facilities, introducing progeny in the wild, and monitoring the captive and wild populations.
• Evidence is summarized that the loss rate calculated for genetic diversity of inner Bay of Fundy salmon is well under 1%.
• The features necessary for a captive breeding program to have a high expectation of maintaining genetic diversity and the possibility of minimizing loss of fitness in the wild can be combined a number of ways, with varying implications for operation costs, likelihood of maintaining the full genetic diversity of the founder stock, and robustness to mistakes or catastrophes.
• For careful captive breeding programs to have a high likelihood of maintaining genetic diversity it is necessary to have a sufficiently large breeding population and to start the program before the wild population has declined to an extent that substantial genetic diversity has already been lost in the wild population.
• Captive breeding and rearing programs should include an effective and comprehensive evaluation and monitoring component.
• Risk management and application of precaution imply that having individual genetic strains in multiple facilities is good protection against catastrophes. However, there are no compelling reasons why a single facility could not support multiple genetic strains as long as operational procedures were well designed and adhered to strictly.
• The evidence is not conclusive with regard to successful reintroduction of populations that have been maintained in captivity. Many examples of failures at re-establishing self-sustaining populations can be traced to either failures to address the threats that posed the original risk, or to captive breeding programs that did not apply appropriate measures.

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