|SREL Reprint #2085|
Genetic and Ecological Guidelines for Species Reintroduction Programs: Application to Great Lakes Fishes
Gary K. Meffe
University of Georgia
ABSTRACT. Complete restoration of the Great Lakes is unlikely, due to
naturalization of exotic species, habitat degradation and destruction, heavy fishing
mortality, lack of native gene pools, and complicated political jurisdictions that
rarely work toward a common vision. A more realistic goal is rehabilitation, a
movement along the trajectory toward complete restoration. Proper rehabilitation
employs an evolutionary-genetic perspective, which protects and works with the
remaining genetic variation available in lake trout or other species of concern. A
difficult question is how to define the units of genetic conservation; one answer is
to determine Evolutionarily Significant Units. To do this, population structure must
be defined, and various conceptual models are here presented that determine
genetic population structure as a function of geographic structure of the habitat.
Several concepts from the developing field of conservation biology should also be
incorporated into lake trout rehabilitation. These include metapopulations-groups
of populations that experience some degree of regular or intermittent gene flow,
and that serve as recolonization sources after local extinctions. Related to this is
"source-sink dynamics, " a recognition that habitats typically are unequal in quality.
Habitat fragmentation is also relevant because it can stop inter-population
movement and disrupt metapopulation structure and source sink dynamics. Finally,
hatcheries should be used in rehabilitation only with great caution and skepticism.
Hatcheries tend to address the symptoms, rather than the causes, offish declines,
and may mask the underlying problems by continually replacing declining fish.
Improved habitat quality, rather than artificial production, is the key to
rehabilitation of the Great Lakes for lake trout and other native species, and
hatcheries should only be used as a stopgap measure to prevent further losses of
SREL Reprint #2085
Meffe, G.K. 1996. Genetic and ecological guidelines for species reintroduction programs. Journal of Great Lakes Research 21:3-9.