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• 11. [Article] Evidence for selective mortality in marine environments: the role of fish migration size, timing, and production type

  To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Inter-Research ...

  Citation × Citation Citation Abstract Copy Title: Evidence for selective mortality in marine environments: the role of fish migration size, timing, and production type Author: Teel, David J., Emmett, Robert L., Miller, Jessica A., Weitkamp, Laurie A., Claiborne, Andrew M. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Inter-Research and can be found at: http://www.int-res.com/journals/meps/meps-home/. Title: Evidence for selective mortality in marine environments: the role of fish migration size, timing, and production type Author: Teel, David J., Emmett, Robert L., Miller, Jessica A., Weitkamp, Laurie A., Claiborne, Andrew M. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Inter-Research and can be found at: http://www.int-res.com/journals/meps/meps-home/. Close

• 12. [Article] Sandy beach surf zones : what is their role in the early life history of Chinook salmon (Oncorhynchus tshawytscha)?

  Early life stages of many marine and diadromous fish species use sandy beach surf zones, which occur along >50% of the world's marine coastlines. This extensive habitat can provide juvenile fishes with ...

  Citation × Citation Citation Abstract Copy Title: Sandy beach surf zones : what is their role in the early life history of Chinook salmon (Oncorhynchus tshawytscha)? Author: Marin Jarrin, Jose R., 1980- Early life stages of many marine and diadromous fish species use sandy beach surf zones, which occur along >50% of the world's marine coastlines. This extensive habitat can provide juvenile fishes with an abundant supply of potential prey and the ability to hide from predators in its shallow turbid waters. Chinook salmon is an anadromous species that migrates to the ocean during their first (subyearlings) or second (yearlings) year of life. The majority of subyearlings reside in estuaries during their first summer season; however, a small number of juveniles also use surf zones. Early marine residence is considered a critical period for Chinook salmon due to high mortality rates; however the role of surf zones in Chinook salmon life history is unclear. Therefore, I determined the distribution of juvenile Chinook salmon on beaches of the eastern North Pacific, compared the migration and growth patterns observed in surf zones and estuaries, identified the factors that accounted for variation in juvenile surf zone catch, explored the factors that influence growth rate variation in surf zones and estuaries, and modeled how growth rates in these coastal habitats may vary in the near future with predicted changes in climate. The majority (94%) of juveniles were caught in surf zones adjacent to estuaries with trough areas, which are beach sections where sand moved by currents and waves produce a trench-like shape. Surf zone fish were collected in significantly lower numbers than estuarine juveniles but entered brackish/ocean waters at similar sizes. Juveniles in surf zones consumed similar organisms (gammarid amphipods, crustacean larvae and insects) as in estuaries. Furthermore, stomach fullness indices (average = 2% of body weight) and growth rates (average = 0.4 mm day⁻¹) were similar in surf zones and estuaries. At one surf zone, juvenile catch was positively correlated to short-term specific growth rates (14 days prior to capture). A bioenergetics modeling approach indicated that given current conditions, consumption rates accounted for more of the variation in growth than prey energetic content and temperature. Climate models predict future increases in fresh water temperature (1.5 to 5.8°C), sea surface temperature (1.2°C) and wave height (0.75 m) that could influence estuarine and surf zone use. Therefore, I developed a local mixing model based on these predictions to estimate future surf zone and estuarine water temperatures in two of the watersheds studied. Based on these temperature projections and the bioenergetics model, I predicted how juvenile specific growth rates would vary in both habitats. I determined that increases in water temperature in both habitats would reduce specific growth rates by 9 to 40% in surf zones and estuaries if diet composition and consumption rates remain similar to present conditions. To compensate for the decline in growth, juveniles may increase their consumption rates or consume more energetically rich prey, if available. If they are not able to compensate, their size at the end of the season may be reduced, which could reduce their overall survival. These results confirm that a small number of suyearling Chinook salmon use sandy beach surf zones, mostly adjacent to estuary mouths, where they experience growth conditions comparable to estuaries. My findings indicate that, in certain situations, juvenile Chinook salmon surf zone use can be influenced by surf zone growth conditions, while variation in growth rates are themselves most strongly influenced by variation in consumption rates in surf zones and estuaries. Predicted changes in coastal western North American climate will likely modify juvenile growth conditions in the next 50 years, and potentially reduce overall survival. Additional insights into the potential impacts of climate change on juvenile salmon will require estimates of changes in the composition, energetic quality and abundance of prey communities inhabiting coastal environments. Title: Sandy beach surf zones : what is their role in the early life history of Chinook salmon (Oncorhynchus tshawytscha)? Author: Marin Jarrin, Jose R., 1980- Early life stages of many marine and diadromous fish species use sandy beach surf zones, which occur along >50% of the world's marine coastlines. This extensive habitat can provide juvenile fishes with an abundant supply of potential prey and the ability to hide from predators in its shallow turbid waters. Chinook salmon is an anadromous species that migrates to the ocean during their first (subyearlings) or second (yearlings) year of life. The majority of subyearlings reside in estuaries during their first summer season; however, a small number of juveniles also use surf zones. Early marine residence is considered a critical period for Chinook salmon due to high mortality rates; however the role of surf zones in Chinook salmon life history is unclear. Therefore, I determined the distribution of juvenile Chinook salmon on beaches of the eastern North Pacific, compared the migration and growth patterns observed in surf zones and estuaries, identified the factors that accounted for variation in juvenile surf zone catch, explored the factors that influence growth rate variation in surf zones and estuaries, and modeled how growth rates in these coastal habitats may vary in the near future with predicted changes in climate. The majority (94%) of juveniles were caught in surf zones adjacent to estuaries with trough areas, which are beach sections where sand moved by currents and waves produce a trench-like shape. Surf zone fish were collected in significantly lower numbers than estuarine juveniles but entered brackish/ocean waters at similar sizes. Juveniles in surf zones consumed similar organisms (gammarid amphipods, crustacean larvae and insects) as in estuaries. Furthermore, stomach fullness indices (average = 2% of body weight) and growth rates (average = 0.4 mm day⁻¹) were similar in surf zones and estuaries. At one surf zone, juvenile catch was positively correlated to short-term specific growth rates (14 days prior to capture). A bioenergetics modeling approach indicated that given current conditions, consumption rates accounted for more of the variation in growth than prey energetic content and temperature. Climate models predict future increases in fresh water temperature (1.5 to 5.8°C), sea surface temperature (1.2°C) and wave height (0.75 m) that could influence estuarine and surf zone use. Therefore, I developed a local mixing model based on these predictions to estimate future surf zone and estuarine water temperatures in two of the watersheds studied. Based on these temperature projections and the bioenergetics model, I predicted how juvenile specific growth rates would vary in both habitats. I determined that increases in water temperature in both habitats would reduce specific growth rates by 9 to 40% in surf zones and estuaries if diet composition and consumption rates remain similar to present conditions. To compensate for the decline in growth, juveniles may increase their consumption rates or consume more energetically rich prey, if available. If they are not able to compensate, their size at the end of the season may be reduced, which could reduce their overall survival. These results confirm that a small number of suyearling Chinook salmon use sandy beach surf zones, mostly adjacent to estuary mouths, where they experience growth conditions comparable to estuaries. My findings indicate that, in certain situations, juvenile Chinook salmon surf zone use can be influenced by surf zone growth conditions, while variation in growth rates are themselves most strongly influenced by variation in consumption rates in surf zones and estuaries. Predicted changes in coastal western North American climate will likely modify juvenile growth conditions in the next 50 years, and potentially reduce overall survival. Additional insights into the potential impacts of climate change on juvenile salmon will require estimates of changes in the composition, energetic quality and abundance of prey communities inhabiting coastal environments. Close

• 13. [Article] The length of residence of juvenile Fall Chinook salmon in Sixes River, Oregon

  This study was designed to provide life history information about juvenile fall Chinook salmon, Oncorhynchus tshawytscha (Walbaum), in a small coastal river by 1) documenting the length of residence of ...

  Citation × Citation Citation Abstract Copy Title: The length of residence of juvenile Fall Chinook salmon in Sixes River, Oregon Author: Reimers, Paul E. This study was designed to provide life history information about juvenile fall Chinook salmon, Oncorhynchus tshawytscha (Walbaum), in a small coastal river by 1) documenting the length of residence of the juveniles throughout the river, 2) exploring several factors possibly influencing their length of residence, and 3) assessing the relative importance of freshwater and estuarine rearing areas for producing returning spawners. The juveniles were followed from their emergence in the spawning streams to their entry into the ocean. Most information on the length of residence of the juveniles was obtained by seining and trapping at various times and locations in the river. Spawning was distributed throughout the tributary streams, but most egg deposition occurred in Dry Creek. Most fish spawned from November to January. Fry emerged from the gravel from March to May. Newly emerged fry moved downstream from the spawning areas in large numbers at night. Based on experimental studies of juvenile behavior, this movement apparently resulted from emergence at night and lack of visual orientation of the fry during darkness. Downstream movement was reduced during increased light levels (daylight or moonlight). This initial movement of fry is thought to assure rapid dispersal of juveniles throughout the river without extensive energy costs of dispersal by a social mechanism. Many juveniles remained in fresh water until early summer. Most then entered the estuary, possibly because of the influence of high temperature in the main river. A small number of fish continued to reside in the cool spawning tributaries. Detailed studies in 1969 showed that juveniles began entering the estuary in spring, but large increases in the population did not occur until June. During the period of increasing abundance, many juveniles were also captured in the ocean surf. The population level in the estuary peaked at about 145,000 fish during July and August and then declined to a low level in autumn. The rate of growth of the juveniles was reduced for three months during the period of high population abundance. Population density is hypothesized as a major cause of the depressed rate of growth of the juveniles. After the population declined in late summer, growth of juveniles again improved. Following the autumn freshets, most fall Chinook salmon remaining in the estuary and those in the cool spawning streams entered the ocean. A few fish from the tributary populations remained in fresh water through the winter and migrated to the ocean as yearlings the following spring. Based on variation in the length of residence of the juveniles in fresh water and the estuary, five types of life histories were defined. Scale patterns from these types were distinguished and returning spawners from the 1965 brood sorted into the various types. The type-3 fish, those remaining in fresh water until early summer and then remaining for a period of improved growth in the estuary, represented about 90 percent of the returning spawners. Based on the return of these type-3 fish, freshwater and estuarine rearing were concluded to be about equally important to fall Chinook salmon in Sixes River. Title: The length of residence of juvenile Fall Chinook salmon in Sixes River, Oregon Author: Reimers, Paul E. This study was designed to provide life history information about juvenile fall Chinook salmon, Oncorhynchus tshawytscha (Walbaum), in a small coastal river by 1) documenting the length of residence of the juveniles throughout the river, 2) exploring several factors possibly influencing their length of residence, and 3) assessing the relative importance of freshwater and estuarine rearing areas for producing returning spawners. The juveniles were followed from their emergence in the spawning streams to their entry into the ocean. Most information on the length of residence of the juveniles was obtained by seining and trapping at various times and locations in the river. Spawning was distributed throughout the tributary streams, but most egg deposition occurred in Dry Creek. Most fish spawned from November to January. Fry emerged from the gravel from March to May. Newly emerged fry moved downstream from the spawning areas in large numbers at night. Based on experimental studies of juvenile behavior, this movement apparently resulted from emergence at night and lack of visual orientation of the fry during darkness. Downstream movement was reduced during increased light levels (daylight or moonlight). This initial movement of fry is thought to assure rapid dispersal of juveniles throughout the river without extensive energy costs of dispersal by a social mechanism. Many juveniles remained in fresh water until early summer. Most then entered the estuary, possibly because of the influence of high temperature in the main river. A small number of fish continued to reside in the cool spawning tributaries. Detailed studies in 1969 showed that juveniles began entering the estuary in spring, but large increases in the population did not occur until June. During the period of increasing abundance, many juveniles were also captured in the ocean surf. The population level in the estuary peaked at about 145,000 fish during July and August and then declined to a low level in autumn. The rate of growth of the juveniles was reduced for three months during the period of high population abundance. Population density is hypothesized as a major cause of the depressed rate of growth of the juveniles. After the population declined in late summer, growth of juveniles again improved. Following the autumn freshets, most fall Chinook salmon remaining in the estuary and those in the cool spawning streams entered the ocean. A few fish from the tributary populations remained in fresh water through the winter and migrated to the ocean as yearlings the following spring. Based on variation in the length of residence of the juveniles in fresh water and the estuary, five types of life histories were defined. Scale patterns from these types were distinguished and returning spawners from the 1965 brood sorted into the various types. The type-3 fish, those remaining in fresh water until early summer and then remaining for a period of improved growth in the estuary, represented about 90 percent of the returning spawners. Based on the return of these type-3 fish, freshwater and estuarine rearing were concluded to be about equally important to fall Chinook salmon in Sixes River. Close

• 14. [Article] Growth, residence, and movement of juvenile Chinook salmon within restored and reference estuarine marsh channels in Salmon River, Oregon.

  Tidal wetland channels provide rearing habitat for juvenile Chinook salmon as they emigrate from freshwater habitat and prepare to enter the ocean. Widespread diking and drainage of estuarine marshes ...

  Citation × Citation Citation Abstract Copy Title: Growth, residence, and movement of juvenile Chinook salmon within restored and reference estuarine marsh channels in Salmon River, Oregon. Author: Hering, David K. Tidal wetland channels provide rearing habitat for juvenile Chinook salmon as they emigrate from freshwater habitat and prepare to enter the ocean. Widespread diking and drainage of estuarine marshes for agricultural and urban development may have contributed to a decline in salmon abundance in the Pacific Northwest, prompting efforts to restore estuarine salmon habitat in the region. I investigated the growth and residence patterns of age-0 Chinook salmon in two blind tidal channels in the Salmon River estuary, Oregon. One channel drained a natural high salt marsh in “reference” condition, and the other channel was in an adjacent salt marsh, restored to tidal inundation in 1996 after being diked and controlled by a tide gate for thirty five years. Recapture of individually marked fish indicated salmon growth rates were similar in the two channels, though growth rates varied more seasonally in the restored site. Average minimum residence times of individual fish were approximately ten days in each channel, and individual salmon were observed up to 79 and 117 days after initial marking in the reference and restored channels, respectively. To characterize movement of age-0 salmon within tidal channels, I tested the feasibility of stationary Passive Integrated Transponder (PIT) detection within a small (approximately 8m wide) tidal channel within the natural marsh system. I found that a stationary PIT detector was an effective tool for monitoring tagged fish movement in a brackish water channel network. Salmon movements in the channel were asymmetrical about high slack tide, with peak movement frequency occurring late during both flood and ebb tide periods. Most movements were in the direction of tidal currents, but 20% of individuals entered the channel against the ebbing tide. Individuals occupied the intertidal channel for a median 4.9 hours and as long as 8.9 hours per tidal cycle, and few were detected moving when water depth was <0.4m. Some individuals used the channel on multiple successive tidal cycles, and others entered intermittently over periods up to 109 days. This research used individual-based fish marking methods to quantify juvenile Chinook salmon behavior and performance within tidal marsh channels, assessing functional equivalence of natural and restored sites and demonstrating the value of such habitats for conservation and restoration of salmon populations. Title: Growth, residence, and movement of juvenile Chinook salmon within restored and reference estuarine marsh channels in Salmon River, Oregon. Author: Hering, David K. Tidal wetland channels provide rearing habitat for juvenile Chinook salmon as they emigrate from freshwater habitat and prepare to enter the ocean. Widespread diking and drainage of estuarine marshes for agricultural and urban development may have contributed to a decline in salmon abundance in the Pacific Northwest, prompting efforts to restore estuarine salmon habitat in the region. I investigated the growth and residence patterns of age-0 Chinook salmon in two blind tidal channels in the Salmon River estuary, Oregon. One channel drained a natural high salt marsh in “reference” condition, and the other channel was in an adjacent salt marsh, restored to tidal inundation in 1996 after being diked and controlled by a tide gate for thirty five years. Recapture of individually marked fish indicated salmon growth rates were similar in the two channels, though growth rates varied more seasonally in the restored site. Average minimum residence times of individual fish were approximately ten days in each channel, and individual salmon were observed up to 79 and 117 days after initial marking in the reference and restored channels, respectively. To characterize movement of age-0 salmon within tidal channels, I tested the feasibility of stationary Passive Integrated Transponder (PIT) detection within a small (approximately 8m wide) tidal channel within the natural marsh system. I found that a stationary PIT detector was an effective tool for monitoring tagged fish movement in a brackish water channel network. Salmon movements in the channel were asymmetrical about high slack tide, with peak movement frequency occurring late during both flood and ebb tide periods. Most movements were in the direction of tidal currents, but 20% of individuals entered the channel against the ebbing tide. Individuals occupied the intertidal channel for a median 4.9 hours and as long as 8.9 hours per tidal cycle, and few were detected moving when water depth was <0.4m. Some individuals used the channel on multiple successive tidal cycles, and others entered intermittently over periods up to 109 days. This research used individual-based fish marking methods to quantify juvenile Chinook salmon behavior and performance within tidal marsh channels, assessing functional equivalence of natural and restored sites and demonstrating the value of such habitats for conservation and restoration of salmon populations. Close