摘要：Commercial harvest of White Suckers Catostomus commersonii for
bait in the American Lobster Homarus americanus industry is minimally
regulated in Maine and there are concerns as to the influence
of increasing harvest. We built a population model using
parameters (i.e. age-specific mortality, age at maturity, and sizespecific
fecundity) from literature and field studies to investigate
the theoretical effects of harvest mortality on age structure.
Because stock-recruitment relations are poorly characterized for
this species, we explored the influence of both Beverton-Holt and
Ricker recruitment processes. Our base model closely resembled
the empirical age structures reported from three unfished lakes in
Maine, with four percent of fish in the modeled spawning run
being age-10 or older. We assessed the additive effects of harvest
mortality on age structure using the full range of possible mortalities.
As expected, increased harvest mortality in the model
resulted in a decline and disappearance of older age-classes such
that few fish greater than age-10 remained in the population
under a realistic harvest mortality scenario. This age-truncation
was qualitatively comparable to data from aggregate age distributions
reported from three commercially harvested lakes in Maine.
Because the loss of older fish may compromise population viability,
this model is a valuable guidance tool for managers to craft
regulation of this growing fishery.
关键词：Age structure ; harvest impacts ; maine ; population modeling ; white sucker
