Predation at Intermountain West Fish Hatcheries

Publication Type:	Journal Article
Year of Publication:	1996
Authors:	Pitt, WC, Conover, MR
Journal:	The Journal of Wildlife Management
Volume:	60
Issue:	3
Date Published:	1996
ISBN Number:	0022541X
Keywords:	Ardea, Ardea herodias, Ardeidae, Egretta, Egretta sacra, Laridae, Larus, Larus californicus, Nycticorax, Nycticorax nycticorax, Pandion, Pandion haliaetus, Pandionidae
Abstract:	During 1993-94, we observed predators and surveyed managers at Intermountain West fish hatcheries to quantify the extent and species responsible for depredation losses. Our field study confirmed hatchery managers' impressions that great blue herons (Ardea herodias), black-crowned night herons (Nycticorax nycticorax), ospreys (Pandion haliaetus), and California gulls (Larus californicus) were the most important predators. At 2 intensively monitored hatcheries, we calculated losses to avian predation to be 7.0 and 0.6% of annual production, in contrast to the managers' estimates of 15% at each hatchery. Feeding mostly on dead or moribund fish, feral cats (Felis catus), raccoons (Procyon lotor), and striped skunks (Mephitis mephitis) had little effect on fish production. Private hatchery managers estimated higher (13%) total depredation losses than did managers of state owned hatcheries (5%). Hatchery managers viewed netting to be the only effective nonlethal control measure.
URL:	http://www.jstor.org/stable/3802080
Short Title:	The Journal of Wildlife Management

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