| Abstract: | Radio-tagged double-crested cormorants (Phalacrocorax auritus) nesting on Middle Island, Ontario and unmarked cormorants in the western basin of Lake Erie were monitored in 1999. Radio-tagged cormorants were located by aircraft and by boat along regular survey routes. In addition, foraging flocks of radio-tagged and unmarked cormorants were located during the boat surveys. Approximately 79% of foraging radio-tagged individuals, and approximately 65% of all foraging flocks were observed within 2.5 km of shore. These percentages were greater than expected based on the percentage of water within 2.5 km of shore. All size classes of flocks examined were found more frequently than expected on water a?? 10 m deep. Trawling data collected annually from 1988 to 1999 during the month of August were used to determine the historical distributions of the four fish species found to comprise the majority of the diet of cormorants in the area. August corresponded to a period when there is maximal overlap in the diets of cormorants and walleye (Stizostedion vitreum) in the area and when the number of foraging cormorants in the area is large. Flocks of cormorants of all size classes examined were not found proportionately more in regions that contained higher than the historical median annual catches of any of the four prey species. These results, coupled with previous bioenergetics studies, suggest that the impact of cormorants on the fishery of the western basin of Lake Erie is localized with respect to depth and distance from shore. |
| Genre: | Article |
| ProdID: | 1000875 |
| Citation Author: | Stapanian, Martin A.; Bur, Michael T.; Tyson, Jeffrey T.; Seamans, Thomas W.; Blackwell, Bradley F. |
| Citation Contributing Office: | Great Lakes Science Center |
| Citation Datum: | |
| Citation Day: | |
| Citation Edition: | |
| Citation Editor: | |
| Citation End Page: | 171 |
| Citation Issue: | 2 |
| Citation Keywords: | |
| Citation Language: | English |
| Citation Larger Work Title: | Journal of Great Lakes Research |
| Citation LatN: | |
| Citation LatS: | |
| Citation LonE: | |
| Citation LonW: | |
| Citation Month: | |
| Citation No Pagination: | |
| Citation Number Of Pages: | 16 |
| Citation Online Only Flag: | |
| Citation Phsyical Description: | p. 155-171 |
| Citation Projection: | |
| Citation Public Comments: | |
| Citation Publisher: | |
| Citation Series: | |
| Citation Series Code: | |
| Citation Series Number: | |
| Citation Search Results Text: | Foraging locations of double-crested cormorants on western Lake Erie: Site characteristics and spatial associations with prey fish densities; 2002; Article; Journal; Journal of Great Lakes Research; Stapanian, Martin A.; Bur, Michael T.; Tyson, Jeffrey T.; Seamans, Thomas W.; Blackwell, Bradley F. |
| Citation Start Page: | 155 |
| Citation Volume: | 28 |
| Citation Year: | 2002 |
| Type: | citation/reference |
| Text: | Foraging locations of double-crested cormorants on western Lake Erie: Site characteristics and spatial associations with prey fish densities; 2002; Article; Journal; Journal of Great Lakes Research; Stapanian, Martin A.; Bur, Michael T.; Tyson, Jeffrey T.; Seamans, Thomas W.; Blackwell, Bradley F. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Tue, 1 Jan 2002 00:00 -0600 |
| Publisher: | |
