Fisheries Behavioral Ecology - Abstracts
De Robertis, A., C.H. Ryer, A. Veloza, and R.D. Brodeur. 2003. Differential effects of turbidity on prey consumption of piscivorous and planktivorous fish. Canadian Journal of Fisheries and Aquatic Sciences 60:1517-1526.
Abstract
Contrast degradation theory predicts that increased turbidity decreases the visibility of objects that are visible
at longer distances more than that of objects that are visible at short distances. Consequently, turbidity should disproportionately decrease feeding rates by piscivorous fish, which feed on larger and more visible prey than particle-feeding
planktivorous fish. We tested this prediction in a series of laboratory feeding experiments, the results of which indicated that prey consumption by two species of planktivorous fish (juvenile chum salmon (Oncorhynchus keta) and
walleye pollock (Theragra chalcogramma)) is much less sensitive to elevated turbidity than piscivorous feeding by
sablefish (Anoplopoma fimbria). Planktivorous feeding in the turbidity range tested (0–40 nephelometric turbidity units
(NTU)) was reduced at high light intensity, but not at low light intensity. Comparatively low (5–10 NTU) turbidity
decreased both the rate at which sablefish pursued prey and the probability of successful prey capture. These results suggest that turbid environments may be advantageous for planktivorous fish because they will be less vulnerable to
predation by piscivores, but will not experience a substantial decrease in their ability to capture zooplankton prey.
Last updated
26 April, 2007
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