O. Heikinheimo, Effect of predation on the low-density dynamics of vendace: significance of the functional response, CAN J FISH, 58(10), 2001, pp. 1909-1923
Citations number
36
Categorie Soggetti
Aquatic Sciences
Journal title
CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES
During the past 20 years, there have been prolonged vendace (Coregonus albu
la) recessions in several Finnish lakes. Hypotheses have been proposed that
predation by brown trout (Salmo trutta m. lacustris) or perch (Perca fluvi
atilis) on young-of-the-year vendace could prevent the recovery of the vend
ace stocks from a low-density state. In this study, dynamic modelling was a
pplied to examine the effect of predation, assuming a dome-shaped spawning
stock-recruitment relationship for vendace, type II or III functional respo
nses to predation by brown trout and perch, and a constant rate of fishing.
The results showed that the form of the functional response is crucial in
determining the significance of the predation on vendace stocks that have a
steep dome-shaped stock-recruitment relationship. In all cases, however, p
redation by perch had more effect than that by brown trout, probably due to
perch occupying the pelagic zone when the vendace stock is sparse. This ma
y make the mortality of vendace increase with decreasing population density
(depensatory mortality) at certain density levels.