Factors influencing density, distribution, and mesohabitat selection of juvenile wild salmonids and residual hatchery winter steelhead

Brignon, William R.; Olson, Douglas E.; Schaller, Howard; Schreck, Carl B.

doi:10.1016/j.aquaculture.2011.04.040

Cited by 3 publications

(1 citation statement)

References 41 publications

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“…In general, hatchery-reared juvenile steelhead are larger than naturally produced O. mykiss in rearing areas where the two groups overlap (McMichael et al 1999;Brignon et al 2012;Snow et al 2013). This was also the case in the South Santiam River in 2013 and 2014, where hatchery steelhead were generally estimated to be between 150-300 mm and most naturally produced O. mykiss were between 100-200 mm.…”

Section: Discussionmentioning

confidence: 81%

Ecological interactions between hatchery summer steelhead and wild Oncorhynchus mykiss in the Willamette River basin, 2014

Harnish¹,

Green²,

Vernon³

et al. 2014

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The purpose of this study was to determine the extent to which juvenile hatchery summer steelhead Oncorhynchus mykiss and wild winter steelhead overlap in space and time, to evaluate the extent of residualism among hatchery summer steelhead in the South Santiam River, and to evaluate the potential for negative ecological interactions among hatchery summer steelhead and wild winter steelhead. Wild winter steelhead populations have declined in the upper Willamette River Basin and are consequently listed as "threatened" under the Endangered Species Act. The U.S. Army Corps of Engineers funded the Pacific Northwest National Laboratory (PNNL) to determine whether releases of non-native hatchery summer steelhead juveniles into the South Santiam River (a tributary of the upper Willamette River) have the potential to negatively affect the river's wild winter steelhead population. The 2014 study objectives were to 1) estimate the proportion of hatchery summer steelhead that residualized in the South Santiam River in 2014, 2) determine the extent to which hatchery and naturally produced O. mykiss overlapped in space and time in the South Santiam River, and 3) characterize the behavioral interactions between hatchery-origin juvenile summer steelhead and naturally produced O. mykiss. We used a combination of radio telemetry and direct observations (i.e., snorkeling) to determine the potential for negative interactions between hatchery summer and wild winter steelhead juveniles in the South Santiam River. Both radio telemetry and direct observations were used to determine the spatial and temporal distribution of hatchery summer steelhead in areas containing naturally produced O. mykiss. In addition, radio telemetry was used to estimate the proportion of hatchery summer steelhead that residualized in the South Santiam River. Direct observations were used to assess ecological interaction rates and types among and between naturally produced and hatchery-origin O. mykiss and to evaluate the overlap in habitat use between the two groups. A total of 199 hatchery summer steelhead juveniles from the South Santiam Hatchery were implanted with radio transmitters on March 20 and 21, 2014. The radio-tagged fish were held in a raceway at the hatchery for 11 to 12 days until the gate was pulled that allowed fish to volitionally leave the raceway to enter the South Santiam River in the Foster Dam tailrace. Thirty-five radio-tagged steelhead (17.6%) did not leave the hatchery during the volitional release period and were euthanized. Radio-tagged fish that did leave the hatchery were detected by fixed receivers located on Foster Dam, at the mouths of the South Santiam and Santiam rivers, in the Willamette River, and during mobile tracking surveys conducted in the South Santiam River. Direct underwater observations were conducted at multiple locations in the South Santiam River between June 14 and July 31, 2014 to characterize the relative fish size, abundance, distribution, and behavioral interactions between residual hatchery summer steelhea...

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Section: Discussionmentioning

confidence: 81%

Ecological interactions between hatchery summer steelhead and wild Oncorhynchus mykiss in the Willamette River basin, 2014

Harnish¹,

Green²,

Vernon³

et al. 2014

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Spatial and Temporal Segregation of Wild and Hatchery Winter Steelhead Populations in Eagle Creek, Oregon

Brignon

2017

N American J Fish Manag

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A segregated hatchery program promotes conservation by limiting the amount of overlap in return timing and spawning locations of hatchery‐ and natural‐origin fish. The objective of the present study was to use radiotelemetry data collected from 2005 to 2007 to better understand the level of spatial and temporal segregation between hatchery and natural‐origin steelhead Oncorhynchus mykiss in the Eagle Creek basin, Oregon. The analysis resulted in three key findings. First, hatchery‐origin winter steelhead were unlikely to migrate into the North Fork Eagle Creek, a tributary that has historically lacked any hatchery releases or influence, suggesting a high level of segregation from the natural‐origin population returning to that stream. Second, hatchery fish arrived at the lower fish ladder on Eagle Creek and at Eagle Creek National Fish Hatchery (NFH) earlier than natural‐origin fish, suggesting that broodstock management practices to maintain an early returning hatchery stock (i.e., temporal segregation) have been somewhat successful. Finally, regardless of the differential arrival timing to Eagle Creek NFH, there is evidence of an increased probability of spatial and temporal overlap of the populations as the return progresses, and this may be explained by successful reproduction of hatchery‐origin fish in main‐stem Eagle Creek. Integrated and segregated hatchery programs should be monitored periodically to ensure that they are meeting their stated goals. Received October 12, 2016; accepted March 14, 2017 Published online May 4, 2017

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The Effects of Rearing Density on Growth, Fin Erosion, Survival, and Migration Behavior of Hatchery Winter Steelhead

Kavanagh

Olson

2014

N American J Aquac

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Juvenile winter steelhead Oncorhynchus mykiss at Eagle Creek National Fish Hatchery in Estacada, Oregon, were reared for three brood years (2004–2006) at raceway densities of 7,500 (214 fish/m3), 15,000 (429 fish/m3), and 22,500 fish (643 fish/m3) to determine the effects of rearing density on growth, fin erosion, survival, adult yield, and migration behavior. Coded wire tags were used to evaluate adult survival, and fish were radio‐tagged to monitor migration times from the hatchery to the mouth of Eagle Creek following volitional release from the hatchery. We found rearing density had a significant effect (P < 0.05) on steelhead growth, fin erosion, and adult survival. Winter steelhead reared in low‐density raceways (13.6 kg/m3 at release) were significantly larger at release, larger at return, had significantly better dorsal fin condition, and had significantly greater smolt‐to‐adult survival rates than did those reared in medium (23.4 kg/m3) and high (35.2 kg/m3) density raceways. No significant relationship between smolt size at release and migration timing was detected; however, the effect of rearing density on fish migration was noticeable in brood year 2004. In that year (2004), smolts from the medium‐ and high‐density groups took from 6 to15 d longer to out‐migrate than those from the low‐density group.

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Factors influencing density, distribution, and mesohabitat selection of juvenile wild salmonids and residual hatchery winter steelhead

Cited by 3 publications

References 41 publications

Ecological interactions between hatchery summer steelhead and wild Oncorhynchus mykiss in the Willamette River basin, 2014

Ecological interactions between hatchery summer steelhead and wild Oncorhynchus mykiss in the Willamette River basin, 2014

Spatial and Temporal Segregation of Wild and Hatchery Winter Steelhead Populations in Eagle Creek, Oregon

The Effects of Rearing Density on Growth, Fin Erosion, Survival, and Migration Behavior of Hatchery Winter Steelhead

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