1
|
Sherker Z, Pellett K, Atkinson J, Damborg J, Trites A. Pacific Great Blue Herons ( Ardea herodias fannini) consume thousands of juvenile salmon ( Oncorhynchus spp.). CAN J ZOOL 2021. [DOI: 10.1139/cjz-2020-0189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
An array of predators that consume juvenile salmon (genus Oncorhynchus Suckley, 1861) may account for the poor returns of adult salmon to the Salish Sea. However, the Pacific Great Blue Heron (Ardea herodias fannini Chapman, 1901) is rarely listed among the known salmon predators, despite being regularly seen near salmon streams. Investigating heron predation by scanning nesting sites within 35 km of three British Columbia (Canada) rivers for fecal remains containing passive integrated transponder (PIT) tags implanted in >100 000 juvenile salmon from 2008 to 2018 yielded 1205 tags, representing a minimum annual predation rate of 0.3%–1.3% of all juvenile salmon. Most of this predation (99%) was caused by ∼420 adult Pacific Great Blue Herons from three heronries. Correcting for tags defecated outside of the heronry raised the predation rates to 0.7%–3.2%, and was as high as 6% during a year of low river flow. Predation occurs during chick-rearing in late spring and accounts for 4.1%–8.4% of the Pacific Great Blue Heron chick diet. Smaller salmon smolts were significantly more susceptible to Pacific Great Blue Heron predation than larger conspecifics. The proximity of heronries relative to salmon-bearing rivers is likely a good predictor of Pacific Great Blue Heron predation on local salmon runs, and can be monitored to assess coast-wide effects of Pacific Great Blue Herons on salmon recovery.
Collapse
Affiliation(s)
- Z.T. Sherker
- Marine Mammal Research Unit, Institute for the Oceans and Fisheries, The University of British Columbia, AERL, 2202 Main Mall, Vancouver, BC V6T 1Z4, Canada
| | - K. Pellett
- South Coast Stock Assessment Division, Fisheries and Oceans Canada, 3225 Stephenson Point Road, Nanaimo, BC V9T 1K3, Canada
| | - J. Atkinson
- Vancouver Island Division, British Columbia Conservation Foundation, 105-1885 Boxwood Road, Nanaimo, BC V9S 5X9, Canada
| | - J. Damborg
- Vancouver Island Division, British Columbia Conservation Foundation, 105-1885 Boxwood Road, Nanaimo, BC V9S 5X9, Canada
| | - A.W. Trites
- Marine Mammal Research Unit, Institute for the Oceans and Fisheries, The University of British Columbia, AERL, 2202 Main Mall, Vancouver, BC V6T 1Z4, Canada
| |
Collapse
|
2
|
Bailey CJ, Moore JW. Resource pulses increase the diversity of successful competitors in a multi‐species stream fish assemblage. Ecosphere 2020. [DOI: 10.1002/ecs2.3211] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- Colin J. Bailey
- Earth to Ocean Research Group Simon Fraser University 8888 University Dr. Burnaby British ColumbiaV5A 1S6USA
| | - Jonathan W. Moore
- Earth to Ocean Research Group Simon Fraser University 8888 University Dr. Burnaby British ColumbiaV5A 1S6USA
| |
Collapse
|