The genetic impacts of human activities on wild fish populations

Abstract

A review of the literature confirms that human activities have caused genetic changes in some wild fish populations, with most of these changes being adverse. These genetic effects include a reduction in growth rate and/or possibly in age/size at sexual maturity in some heavily fished populations. There was also considerable evidence of hybridization between wild and released populations (sometimes resulting in the loss of the wild population) and the extinction of some wild populations due to habitat changes and to competition and/or predation from introduced species.

There is a need to monitor wild fish populations for genetic change, with particular emphasis on exploited populations of prominent economic or recreational value. This is best done by directly examining either the genome (e.g., genetic fingerprinting, with gene probes, DNA sequencing) or gene products (e.g., protein electrophoresis). In order to detect genetic change, it is necessary to have access to at least two chronologically distinct samples of the same population. As DNA is also relatively inexpensive to store, DNA depositories could be established in order to provide a historical record of the genetic composition of populations of either commercial or scientific interest.

Key words:

• genetic change
• selection
• hybridization
• translocation