Dynamics of recruitment
in larval sea lamprey populations
Like many fish
species, sea lamprey exhibit large
variations in recruitment from year to year. As well, little is known
about the
stock-recruitment relationship for sea lamprey, and thus the degree to
which
density-dependent factors affect population dynamics in the Great Lakes. Recruitment variation and
density dependence (also known as
compensation) can have a large influence on the efficacy of sea lamprey
control
strategies that target reproductive success, such as the release of
sterile
males into spawning grounds. We have investigated the dynamics of sea
lamprey
recruitment in Great Lakes tributary streams
by:
-
measuring
spawner numbers
and the resulting recruitment at age- 1 to learn about the sea lamprey
stock-recruitment relationship in Great Lakes
streams;
- studying possible
mechanisms of density dependence in larval lamprey, particularly during
their
first year of life;
- monitoring
lamprey
recruitment over time to identify possible causes of interannual
variation in
recruitment and to separate “stream” and
“year” effects;
- establishing
single
age-classes of larvae in two streams to develop known-age populations
of larvae;
- using known-age populations to validate statolith age determination, since accurate estimation of
age is
important for measuring recruitment; and
- developing, analyzing, and
applying models that simulate sea lamprey management options in the
presence of
uncertainty about recruitment.
|
 |
