Cumulative Effects of Avian Predation on Upper Columbia River Steelhead

Evans, Allen F.; Payton, Quinn; Cramer, Bradley M.; Collis, Ken; Hostetter, Nathan J.; Roby, Daniel D.; Dotson, Curtis

doi:10.1002/tafs.10197

Cited by 14 publications

(76 citation statements)

References 32 publications

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“…Large numbers of bald eagles Haliaeetus leucocephalus overwinter in eastern Oklahoma, including the Spavinaw Creek catchment where they target prey, including fishes (Lish 1973). Predation from birds is common for salmonids (Evans et al 2019), and that may have contributed to increased mortality following stocking while hatchery fish were still naive to predators. Difficulties transitioning from hatchery to natural food and behavior may also reduce survival immediately after stocking.…”

Section: Discussionmentioning

confidence: 99%

Survival and Movement Patterns of Rainbow Trout Stocked in a Groundwater‐Influenced Warmwater Stream

Wolf

Brewer

2021

N American J Fish Manag

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Stocking Rainbow Trout Oncorhynchus mykiss to create additional angling opportunities is common; however, the spatial and temporal dynamics of such stocking practices are unclear in groundwater‐influenced, warmwater streams. Our objectives were to determine Rainbow Trout dispersal from a stocking location on Spavinaw Creek, Oklahoma and to quantify apparent survival of two cohorts of Rainbow Trout stocked in November 2018 and February 2019. Rainbow Trout were PIT‐tagged prior to autumn (N = 495) and winter (N = 605) stocking and located poststocking using both an active floating array and two passive fixed arrays. We actively tracked a 6‐km extent every 2–3 weeks poststocking and found that PIT‐tagged Rainbow Trout dispersal ranged from 0 to 4 km with ~90% of detected tagged fish remaining within 1 km of the stocking location. Directional movement by stocked Rainbow Trout was evident with upstream movements related to increases in daily water discharge and downstream movements related to decreases in daily discharge. Estimated apparent weekly survival of Rainbow Trout was lowest during the first 2 weeks poststocking (91% and 75% for autumn and spring cohorts, respectively). Apparent weekly survival rates for both autumn and spring stocked fish increased through winter and spring when maximum water temperatures were below 25℃, reaching survival rates of 99% by the end of spring. Rainbow Trout persisted in Spavinaw Creek throughout the summer; however, the weekly apparent survival rate declined for both cohorts (93%) when maximum daily water temperatures exceeded 25°C. Our results can be used to guide stocking decisions in similar warmwater streams and suggest that Rainbow Trout persist through spring and summer poststocking under the conditions encountered during our study.

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Section: Discussionmentioning

confidence: 99%

Survival and Movement Patterns of Rainbow Trout Stocked in a Groundwater‐Influenced Warmwater Stream

Wolf

Brewer

2021

N American J Fish Manag

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“…We also collated detections of these tags at two sites downstream of Bonneville Dam where biologists sample with portable antennas: within the Columbia River estuary (Towed PIT array–TWX, rkm 75) and at a colony of piscivorous double‐crested cormorants Phalacrocorax auritus and Caspian terns Hydroprogne caspia on East Sand Island (ESANIS, rkm 8), near the mouth of the Columbia River. The ESANIS site is intended to recover PIT tags from depredated fish from cormorants and terns that forage in the Columbia River and estuary downstream from Bonneville Dam (e.g., Evans et al 2019). From these detection data, we were able to generate encounter histories for individual PIT tags that spanned implantation or release within the hatchery, transfer out of the hatchery to the river release location, and nearly the entire freshwater migration corridor from river release site to the Pacific Ocean.…”

Section: Methodsmentioning

confidence: 99%

Ingestion of PIT Tags by Hatchery‐Reared Juvenile Steelhead and Subsequent Detection at Main‐Stem Dams in the Columbia River Basin

Peterson

Engle

2021

N American J Fish Manag

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During the past 30 years, millions of hatchery‐reared Pacific salmon Oncorhynchus spp. have been implanted with PIT tags to estimate their survival and track their migration through the extensive system of hydroelectric dams in the Columbia River basin. The mark–recapture models that are used for these analyses assume that the tags are not lost, making it important to understand retention rates for PIT tags and the fate of shed tags. To understand the potential fate of shed PIT tags in a production hatchery, we distributed 12‐mm PIT tags in two traditional cement raceways and the two circular tanks of a partial reuse aquaculture system (PRAS) containing juvenile summer steelhead O. mykiss. We then monitored the detection of these PIT tags at the time that the fish were released as smolts and at main‐stem dams during their migration. The probability that a loose PIT tag was inside a steelhead smolt at release ranged from 0.200 to 0.519 across the raceways and tanks, confirming that the fish consumed tags during hatchery rearing. Detections at six dams—including one located 1,208 km from the release site—and up to 36 d after smolt release confirmed that some ingested tags remained in the steelhead during their migration. The estimates of apparent survival for smolts with ingested and implanted PIT tags suggested that some ingested tags were being excreted during migration through the Columbia River basin. The results highlight the need to reevaluate assumptions about the fate of shed PIT tags in steelhead production hatcheries and ensure that biologists and managers have reliable estimates of tag retention.

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“…Previous research has identified predation by Caspian terns ( Hydroprogne caspia , hereafter “terns”) and double-crested cormorants ( Nannopterum auritum , hereafter “cormorants”) and consumption by California gulls ( Larus californicus ) and ring-billed gulls ( L . delawarensis , collectively hereafter “gulls”) as a substantial mortality factor for some salmonid species and populations in the CRB in some years [ 4 – 7 ]. Previous studies were largely focused on quantifying the effects of individual breeding colonies [ 4 – 6 , 8 , 9 ]; however, most salmonid populations, like those originating from the Snake River, must migrate through the foraging ranges of breeding birds from multiple colonies during seaward migration [ 6 , 10 ].…”

Section: Introductionmentioning

confidence: 99%

Cumulative effects of piscivorous colonial waterbirds on juvenile salmonids: A multi predator-prey species evaluation

et al. 2022

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We investigated the cumulative effects of predation by piscivorous colonial waterbirds on the survival of multiple salmonid (Oncorhynchus spp.) populations listed under the U.S. Endangered Species Act (ESA) and determined what proportion of all sources of fish mortality (1 –survival) were due to birds in the Columbia River basin, USA. Anadromous juvenile salmonids (smolts) were exposed to predation by Caspian terns (Hydroprogne caspia), double-crested cormorants (Nannopterum auritum), California gulls (Larus californicus), and ring-billed gulls (L. delawarensis), birds known to consume both live and dead fish. Avian consumption and survival probabilities (proportion of available fish consumed or alive) were estimated for steelhead trout (O. mykiss), yearling Chinook salmon (O. tshawytscha), sub-yearling Chinook salmon, and sockeye salmon (O. nerka) during out-migration from the lower Snake River to the Pacific Ocean during an 11-year study period (2008–2018). Results indicated that probabilities of avian consumption varied greatly across salmonid populations, bird species, colony location, river reach, and year. Cumulative consumption probabilities (consumption by birds from all colonies combined) were consistently the highest for steelhead, with annual estimates ranging from 0.22 (95% credible interval = 0.20–0.26) to 0.51 (0.43–0.60) of available smolts. The cumulative effects of avian consumption were significantly lower for yearling and sub-yearling Chinook salmon, with consumption probabilities ranging annually from 0.04 (0.02–0.07) to 0.10 (0.07–0.15) and from 0.06 (0.3–0.09) to 0.15 (0.10–0.23), respectively. Avian consumption probabilities for sockeye salmon smolts was generally higher than for Chinook salmon smolts, but lower than for steelhead smolts, ranging annually from 0.08 (0.03–0.22) to 0.25 (0.14–0.44). Although annual consumption probabilities for birds from certain colonies were more than 0.20 of available smolts, probabilities from other colonies were less than 0.01 of available smolts, indicating that not all colonies of birds posed a substantial risk to smolt mortality. Consumption probabilities were lowest for small colonies and for colonies located a considerable distance from the Snake and Columbia rivers. Total mortality attributed to avian consumption was relatively small for Chinook salmon (less than 10%) but was the single greatest source of mortality for steelhead (greater than 50%) in all years evaluated. Results suggest that the potential benefits to salmonid populations of managing birds to reduce smolt mortality would vary widely depending on the salmonid population, the species of bird, and the size and location of the breeding colony.

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Cumulative Effects of Avian Predation on Upper Columbia River Steelhead

Cited by 14 publications

References 32 publications

Survival and Movement Patterns of Rainbow Trout Stocked in a Groundwater‐Influenced Warmwater Stream

Survival and Movement Patterns of Rainbow Trout Stocked in a Groundwater‐Influenced Warmwater Stream

Ingestion of PIT Tags by Hatchery‐Reared Juvenile Steelhead and Subsequent Detection at Main‐Stem Dams in the Columbia River Basin

Cumulative effects of piscivorous colonial waterbirds on juvenile salmonids: A multi predator-prey species evaluation

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