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Observations on Double-crested Cormorants ( Phalacrocorax auritus ) at sportfishing waters in southwestern Utah
| Content Provider | Semantic Scholar |
|---|---|
| Author | Ottenbacher, Michael J. Hepworth, Dale K. Berg, Louis N. |
| Copyright Year | 1994 |
| Abstract | -Counts of Double-crested Cormorants (Fhalacroconu aurit-us) were made at 13 reservoirs and lakes in southwestern Utah during 1989-91 to determine current abundance of that species. Food habits of cormorants were studied at three of the reservoirs in 1989. Data were also collected on trout abundance during standardized gill-netting to make comparisons between cormorant numbers and trout abundance. Cormorants were observed at all waters studied except one and were generally most numerous during the spring as they migrated through the area. Estimated connorant abundance ranged from 0 to 34 bud-days per ha and was highest at the larger, lower-elevation reservoirs. Connorants were summer residents at several of the larger reservoirs and nested successfully at Piute Reservoir. Trout accounted for 24-81% ofthe diet ofcormorants. with Utah chubs constituting most of the remainder of the diet. Estimates of the annual consumption of fish by cormorants ranged from 0 to 15.8 kg per ha. The index of trout abundance was inversely related to cormorant abundance (P < .01) at the waters studied. Cormorants apparently have increased in numbers and extend· ed their range in southwestem Utah during the past decade. This change may be the result of factors that have led to similar changes throughout North America as weD as some factors unique to Utah. Methods to mitigate the impact of predation by pisdvorous birds on sportfisheries are discussed. The Utah Division of Wildlife Resources has initiated a new management plan at MinersviUe Reservoir that incorporates piscivorous birds into sportHsh management at that reservoir. |
| Starting Page | 8 |
| Ending Page | 8 |
| Page Count | 1 |
| File Format | PDF HTM / HTML |
| Volume Number | 54 |
| Alternate Webpage(s) | https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=2887&context=gbn&httpsredir=1&referer= |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
