Author/s: Blackwell B.F., Dolbeer R.A. & Tyson L.A. 2000.

Title: Lethal control of piscivorous birds at aquaculture facilities in the northeast United States: Effects on populations.

Journal: North American Journal of Aquaculture, 62(4): 300-307.

Abstract: Predation by piscivorous birds is considered a substantial threat to the aquaculture industry. However, lethal control of birds at aquaculture facilit ies has raised concerns about the effects on the distribution and abundance of populations of the species killed. We examined the relationship between numbers of piscivorous birds reported killed under U.S. Fish and Wildlife Service (USFWS) permits at aquaculture facilities in New York, New Jersey, and Pennsylvania and species population trends within the respective states. The USFWS issued 26 permits to 9 facilities from 1985 through September 1 997. Eight species appeared on permits, but only six species were reported killed: black-crowned night-herons Nycticorax nycticorax double-crested cor morants Phalacrocorax auritus, great blue herons Ardea herodias, herring gulls Larus argentatus, ring-billed gulls L. delawarensis, and mallards Anas platyrhynchos. Over 13 years, the authorized number of birds to be killed per species or group (e.g., gulls) ranged from 5 to 800 (mean = 240, SD = 30 0), whereas the reported number of birds killed per species or group (1985- 1996) ranged from 0 to 289 (mean = 83, SD = 118). Across states and species, the number of birds authorized to be killed per permit ranged from 2 to 6 0 (mean = 27, SD = 20), whereas reported kills ranged from 0 to 45 (mean = 12, SD = 10). Herring gulls (N = 272) and great blue herons (N = 163) were the most frequently killed species. The number of birds reported killed, re lative to systematic long-term population trends, is considered to have had negligible effects on the population status of the respective species.

Address: Blackwell, BF US Anim & Plant Hlth Inspect Serv, USDA, Wildlife Serv, NatlWildlife Res Ctr,Ohio Field Stn, 6100 Columbus Ave, Sandusky, OH 44870 USAUS Anim & Plant Hlth Inspect Serv 6100 Columbus Ave Sandusky OH USA 44870

 Cormorants

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