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• 31. [Article] Market Interactions between Aquaculture and Common-Property Fisheries: Examining the Empirical Evidence from the Bristol Bay Sockeye Salmon Fishery in Alaska

  The impressive growth of world aquaculture has led to profound transformations in the economic structure of several capture fisheries. Evidence from the Alaska salmon fisheries supports this argument as ...

  Citation × Citation Citation Abstract Copy Title: Market Interactions between Aquaculture and Common-Property Fisheries: Examining the Empirical Evidence from the Bristol Bay Sockeye Salmon Fishery in Alaska Author: Valderrama, Diego, Anderson, James The impressive growth of world aquaculture has led to profound transformations in the economic structure of several capture fisheries. Evidence from the Alaska salmon fisheries supports this argument as a connection has been suggested between the recent trends of declining ex-vessel prices and the rapid development of salmon farming elsewhere in the world. In Bristol Bay, home of the largest sockeye salmon runs in the globe, participation in the limited-entry fishery has declined by approximately 20% since 2001. Likewise, permit market values have plummeted to historic low levels, with economic conditions not likely to improve significantly in the mid-term future. To examine this problem, we develop a formal analytical framework for the study of market interactions between a limited-entry fishery and an aquaculture sector. We adapt the model of regulated open-access developed by Homans and Wilen to examine the implications of aquaculture development on the actions of fishermen and the regulatory sector in a restricted-access setting. Results indicate that the emergence of a low-cost aquaculture sector brings about important structural changes in the restricted-access fishery, rendering limited-entry regulations irrelevant as participation rates decline due to the falling prices. An important implication is that, despite the limited-entry constraint, the fishery moves to an institutional arrangement closer to regulated open access, with resource rents drastically reduced. Model predictions are compared with the empirical evidence available from the Bristol Bay sockeye fishery. The advantages of cooperative management relative to the current competitive structure of the fishery are highlighted. Title: Market Interactions between Aquaculture and Common-Property Fisheries: Examining the Empirical Evidence from the Bristol Bay Sockeye Salmon Fishery in Alaska Author: Valderrama, Diego, Anderson, James The impressive growth of world aquaculture has led to profound transformations in the economic structure of several capture fisheries. Evidence from the Alaska salmon fisheries supports this argument as a connection has been suggested between the recent trends of declining ex-vessel prices and the rapid development of salmon farming elsewhere in the world. In Bristol Bay, home of the largest sockeye salmon runs in the globe, participation in the limited-entry fishery has declined by approximately 20% since 2001. Likewise, permit market values have plummeted to historic low levels, with economic conditions not likely to improve significantly in the mid-term future. To examine this problem, we develop a formal analytical framework for the study of market interactions between a limited-entry fishery and an aquaculture sector. We adapt the model of regulated open-access developed by Homans and Wilen to examine the implications of aquaculture development on the actions of fishermen and the regulatory sector in a restricted-access setting. Results indicate that the emergence of a low-cost aquaculture sector brings about important structural changes in the restricted-access fishery, rendering limited-entry regulations irrelevant as participation rates decline due to the falling prices. An important implication is that, despite the limited-entry constraint, the fishery moves to an institutional arrangement closer to regulated open access, with resource rents drastically reduced. Model predictions are compared with the empirical evidence available from the Bristol Bay sockeye fishery. The advantages of cooperative management relative to the current competitive structure of the fishery are highlighted. Close

• 32. [Article] Irrigation, Power, and Salmon: The Case for Voluntary Water Transfers in the Columbia Basin

  This paper begins with a brief history of water law in the west, illustrating the roots of conflict over water allocation. A more detailed examination of activities in the Columbia Basin follows, describing ...

  Citation × Citation Citation Abstract Copy Title: Irrigation, Power, and Salmon: The Case for Voluntary Water Transfers in the Columbia Basin Author: Kuhner, Eric Year: 1996 This paper begins with a brief history of water law in the west, illustrating the roots of conflict over water allocation. A more detailed examination of activities in the Columbia Basin follows, describing the many parties affected by issues of water use and the overlapping institutional structures that govern the river and its water. Sources of pressure to change the current pattern of water use are then considered. These include requirements to protect endangered salmon runs and the change over time in the relative values of water for power production and irrigation. This section demonstrates how changes in the value of resources can create conflict when resource allocations are inflexible. Alternative approaches to water allocation are then detailed. An argument is made that water use on the Columbia should be flexible, and that the ability to transfer water more easily from one use to another would be beneficial. The potential economic, social, and environmental benefits and costs of water transfers are also considered. The final section of the paper looks at barriers to water transfers and recommendations for institutional change. The section offers examples of market structures and policy options that might overcome some of the obstacles to water transfers. The argument for a more flexible system of water allocation is then summarized. Title: Irrigation, Power, and Salmon: The Case for Voluntary Water Transfers in the Columbia Basin Author: Kuhner, Eric Year: 1996 This paper begins with a brief history of water law in the west, illustrating the roots of conflict over water allocation. A more detailed examination of activities in the Columbia Basin follows, describing the many parties affected by issues of water use and the overlapping institutional structures that govern the river and its water. Sources of pressure to change the current pattern of water use are then considered. These include requirements to protect endangered salmon runs and the change over time in the relative values of water for power production and irrigation. This section demonstrates how changes in the value of resources can create conflict when resource allocations are inflexible. Alternative approaches to water allocation are then detailed. An argument is made that water use on the Columbia should be flexible, and that the ability to transfer water more easily from one use to another would be beneficial. The potential economic, social, and environmental benefits and costs of water transfers are also considered. The final section of the paper looks at barriers to water transfers and recommendations for institutional change. The section offers examples of market structures and policy options that might overcome some of the obstacles to water transfers. The argument for a more flexible system of water allocation is then summarized. Close

• 33. [Article] Expansion and Consolidation in The British Columbia Salmon Processing Industry

  Research Paper

  Citation × Citation Citation Abstract Copy Title: Expansion and Consolidation in The British Columbia Salmon Processing Industry Author: Millerd, Frank Research Paper Title: Expansion and Consolidation in The British Columbia Salmon Processing Industry Author: Millerd, Frank Research Paper Close

• 34. [Article] Oregon coastal community water supply assessment

  On the Oregon coast, however, the issue of water supply has become paramount, especially given the need to restore instream flows in order to restore coastal salmon runs and meet water quality standards. ...

  Citation × Citation Citation Abstract Copy Title: Oregon coastal community water supply assessment Author: Achterman, Gail, Rolston, Irene, Davis-Born, Renee, Institute for Natural Resources, Gaines, Lisa On the Oregon coast, however, the issue of water supply has become paramount, especially given the need to restore instream flows in order to restore coastal salmon runs and meet water quality standards. With the ebb and flow of population and the economic growth of Oregon coastal communities, three hypotheses have been generated about the ability of these communities to meet future water supply needs. The purpose of this project was to better understand the challenges and opportunities facing coastal community water suppliers as a whole and to ultimately improve the prospects for meeting future water needs. Findings show that contrary to the first hypothesis, most of those interviewed do not think that economic development is constrained by waters supply. However, it does appear that it would be difficult for state economic development officials to match businesses and industries interested in relocating to the Oregon coast with community water supply availability and reliability. Findings also show that the major problem facing community water suppliers in preparing water management and conservation plans cited by interviewees is financial. Though Oregon’s coastal communities face several planning, management, physical, economic, and regulatory challenges in preparing for future water supply needs, numerous partnership, conservation, and research and training opportunities exist. What is needed is an opportunity for a facilitated process of restructuring water supply systems. Title: Oregon coastal community water supply assessment Author: Achterman, Gail, Rolston, Irene, Davis-Born, Renee, Institute for Natural Resources, Gaines, Lisa On the Oregon coast, however, the issue of water supply has become paramount, especially given the need to restore instream flows in order to restore coastal salmon runs and meet water quality standards. With the ebb and flow of population and the economic growth of Oregon coastal communities, three hypotheses have been generated about the ability of these communities to meet future water supply needs. The purpose of this project was to better understand the challenges and opportunities facing coastal community water suppliers as a whole and to ultimately improve the prospects for meeting future water needs. Findings show that contrary to the first hypothesis, most of those interviewed do not think that economic development is constrained by waters supply. However, it does appear that it would be difficult for state economic development officials to match businesses and industries interested in relocating to the Oregon coast with community water supply availability and reliability. Findings also show that the major problem facing community water suppliers in preparing water management and conservation plans cited by interviewees is financial. Though Oregon’s coastal communities face several planning, management, physical, economic, and regulatory challenges in preparing for future water supply needs, numerous partnership, conservation, and research and training opportunities exist. What is needed is an opportunity for a facilitated process of restructuring water supply systems. Close

• 35. [Article] Oregon Wildlife; Vol.39 No.8 (November-December 1984)

  Contents: What do Elk Hunters Want? - p.3-6; Salmon Begin Fall Run - p.7; Playing Radio Tag in the Wilds [Radio tags on wildlife] - p.8-9; Watchable Wildlife in Central Oregon - p.10-11; Deer Mouse - p...

  Citation × Citation Citation Abstract Copy Title: Oregon Wildlife; Vol.39 No.8 (November-December 1984) Author: Oregon. Department of Fish and Wildlife Contents: What do Elk Hunters Want? - p.3-6; Salmon Begin Fall Run - p.7; Playing Radio Tag in the Wilds [Radio tags on wildlife] - p.8-9; Watchable Wildlife in Central Oregon - p.10-11; Deer Mouse - p.13 Title: Oregon Wildlife; Vol.39 No.8 (November-December 1984) Author: Oregon. Department of Fish and Wildlife Contents: What do Elk Hunters Want? - p.3-6; Salmon Begin Fall Run - p.7; Playing Radio Tag in the Wilds [Radio tags on wildlife] - p.8-9; Watchable Wildlife in Central Oregon - p.10-11; Deer Mouse - p.13 Close

• 36. [Article] Oregon coastal salmon and steelhead tagging programs

  Part I. To aid in the management of the Tillamook Bay commercial salmon fishery, a tagging program was conducted on the salmon and steelhead trout runs in 1953. General migration behavior, the minimum ...

  Citation × Citation Citation Abstract Copy Title: Oregon coastal salmon and steelhead tagging programs Author: Henry, Kenneth A., Morgan, Alfred R. Part I. To aid in the management of the Tillamook Bay commercial salmon fishery, a tagging program was conducted on the salmon and steelhead trout runs in 1953. General migration behavior, the minimum length of time the fish remained in the fishery, population sizes, and fishing mortalities were determined from this study. Part II. To aid in the management of the Siletz River commercial salmon fishery, a tagging program was conducted on the salmon and steelhead trout runs in 1954. General migration behavior, the minimum length of time fish remained in the fishery, population estimates, and fishing mortalities were determined. Title: Oregon coastal salmon and steelhead tagging programs Author: Henry, Kenneth A., Morgan, Alfred R. Part I. To aid in the management of the Tillamook Bay commercial salmon fishery, a tagging program was conducted on the salmon and steelhead trout runs in 1953. General migration behavior, the minimum length of time the fish remained in the fishery, population sizes, and fishing mortalities were determined from this study. Part II. To aid in the management of the Siletz River commercial salmon fishery, a tagging program was conducted on the salmon and steelhead trout runs in 1954. General migration behavior, the minimum length of time fish remained in the fishery, population estimates, and fishing mortalities were determined. Close

• 37. [Article] Geospatial depiction of fall run Chinook Salmon in Wallowa County

  This product is for informational purposes and may not have been prepared for, or be suitable for legal, engineering, or surveying purposes. Users of this information should review or consult the primary ...

  Citation × Citation Citation Abstract Copy Title: Geospatial depiction of fall run Chinook Salmon in Wallowa County Author: Thomas, Samuel, Department of Fish and Wildlife, State of Oregon, Oregon State University This product is for informational purposes and may not have been prepared for, or be suitable for legal, engineering, or surveying purposes. Users of this information should review or consult the primary data and information sources to verify the purpose and limitations. The data is provided as-is, without warranty. Title: Geospatial depiction of fall run Chinook Salmon in Wallowa County Author: Thomas, Samuel, Department of Fish and Wildlife, State of Oregon, Oregon State University This product is for informational purposes and may not have been prepared for, or be suitable for legal, engineering, or surveying purposes. Users of this information should review or consult the primary data and information sources to verify the purpose and limitations. The data is provided as-is, without warranty. Close

• 38. [Article] Factors affecting the abundance of fall chinook salmon in the Columbia River

  A study of the population ecology of Columbia River fall chinook salmon, Oncorhynchus tshawytscha (Walbaum), was made in an attempt to determine the cause of a serious decline in this run which occurred in ...

  Citation × Citation Citation Abstract Copy Title: Factors affecting the abundance of fall chinook salmon in the Columbia River Author: Van Hyning, Jack M. A study of the population ecology of Columbia River fall chinook salmon, Oncorhynchus tshawytscha (Walbaum), was made in an attempt to determine the cause of a serious decline in this run which occurred in the early 1950's. Fluctuations in abundance of major salmon runs the North Pacific were examined to detect any coastwide pattern. Only chinook salmon in Cook Inlet, Alaska, and chum salmon from Oregon to southwestern Alaska showed a similar trend. The following life history stages broken down into pre- and post-decline years were examined: (1) marine life including distribution and migration, growth and maturity, survival rate, oceanography, and commercial and sport fisheries; (2) upstream migration including river fisheries, gear selectivity, size and age composition of the run, escapement, and influence of dams, diseases, and water quality; (3) reproduction and incubation including spawning areas and spawning and incubation conditions; and (4) downstream migration which included predation, dams and reservoirs, diseases, flow, turbidity and temperature, and estuary life. Salient points of the analysis were: (1) a change in the maturity and survival pattern based on tagged and fin-clipped fish recovered before and after 1950; (2) a significant negative correlation between sea-water temperature during a year class' first year at sea and subsequent survival; (3) a large increase in the ocean fisheries coincident with the decline in the run; (4) catch-effort statistics of the ocean fishery show a near classic example of the effect of overexploitation; (5) estimates of the contribution of Columbia River chinook to the ocean fisheries based on tag recoveries could be underestimates rather than overestimates; (6) a significant inverse correlation between estimated ocean catch of Columbia River fall chinook and numbers entering the river; (7) size and age composition of the ocean and river catches decreased coincident with the decline in the run; (8) the gill-net fishery shows little size selectivity by age, size, or sex in the dominant group; (9) fluctuations in abundance of hatchery stocks are related to differences in survival between fingerling and adult; (10) hatchery, lower river, and upriver populations fluctuate in abundance in much the same pattern; (11) optimum escapement is between 90,000 and 100,000 adults, a value that was exceeded during most years; (12) a highly significant negative correlation between numbers of spawners and return per spawner; (13) most of the early dams had no direct effect on fall chinook and the decline in productivity occurred when river conditions were relatively stable; (14) temperatures at time of migration and spawning for fall chinook have not increased enough to be a serious mortality factor; (15) little relationship between flow, turbidity, and temperature at time of downstream migration and subsequent return was evident except that high temperatures and high flows (and turbidities) tended to produce poorer runs during certain time periods; and (16) predation and delay of smolts in reservoirs are largely unknown factors, but circumstantial evidence suggests that they were not important in regulating fall chinook numbers during the period of the study. Finally, variables that appeared to bear some relationship to fluctuations in abundance of fall chinook were submitted to multiple regression analysis. For the predecline period (1938-46 brood years), sea-water temperature and ocean troll fishing effort were significant variables (R² = 0.74). For post decline years (1947-59 broods), troll had the most influence on total return with ocean temperature and escapement having lesser effects. For the combined years, troll intensity and ocean temperature were the significant variables (R² = 0.572). Entering interaction of river flow at downstream migration with the other variables brought R² to 0.754 which means that 75% of the variability in the returning run could be accounted for by these three factors. Return per spawner was so heavily influenced by numbers of spawners that the other factors assumed negligible importance. Equations were derived that predicted the returning run in close agreement with the actual run size. Substituting a low and constant troll fishing effort in the equation resulted in the predicted run maintaining the average predecline level. The increase in ocean fishing was the main contributor to the decline of the Columbia River fall chinook run as shown by correlation, by analogy, and by the process of elimination. To demonstrate why other chinook runs have not shown similar declines, it was shown that due to several unique features in Columbia River fall chinook life history they are exposed to much more ocean fishing than other populations. It was emphasized that these conclusions should not be extrapolated to the future or to other species or runs of salmon. Title: Factors affecting the abundance of fall chinook salmon in the Columbia River Author: Van Hyning, Jack M. A study of the population ecology of Columbia River fall chinook salmon, Oncorhynchus tshawytscha (Walbaum), was made in an attempt to determine the cause of a serious decline in this run which occurred in the early 1950's. Fluctuations in abundance of major salmon runs the North Pacific were examined to detect any coastwide pattern. Only chinook salmon in Cook Inlet, Alaska, and chum salmon from Oregon to southwestern Alaska showed a similar trend. The following life history stages broken down into pre- and post-decline years were examined: (1) marine life including distribution and migration, growth and maturity, survival rate, oceanography, and commercial and sport fisheries; (2) upstream migration including river fisheries, gear selectivity, size and age composition of the run, escapement, and influence of dams, diseases, and water quality; (3) reproduction and incubation including spawning areas and spawning and incubation conditions; and (4) downstream migration which included predation, dams and reservoirs, diseases, flow, turbidity and temperature, and estuary life. Salient points of the analysis were: (1) a change in the maturity and survival pattern based on tagged and fin-clipped fish recovered before and after 1950; (2) a significant negative correlation between sea-water temperature during a year class' first year at sea and subsequent survival; (3) a large increase in the ocean fisheries coincident with the decline in the run; (4) catch-effort statistics of the ocean fishery show a near classic example of the effect of overexploitation; (5) estimates of the contribution of Columbia River chinook to the ocean fisheries based on tag recoveries could be underestimates rather than overestimates; (6) a significant inverse correlation between estimated ocean catch of Columbia River fall chinook and numbers entering the river; (7) size and age composition of the ocean and river catches decreased coincident with the decline in the run; (8) the gill-net fishery shows little size selectivity by age, size, or sex in the dominant group; (9) fluctuations in abundance of hatchery stocks are related to differences in survival between fingerling and adult; (10) hatchery, lower river, and upriver populations fluctuate in abundance in much the same pattern; (11) optimum escapement is between 90,000 and 100,000 adults, a value that was exceeded during most years; (12) a highly significant negative correlation between numbers of spawners and return per spawner; (13) most of the early dams had no direct effect on fall chinook and the decline in productivity occurred when river conditions were relatively stable; (14) temperatures at time of migration and spawning for fall chinook have not increased enough to be a serious mortality factor; (15) little relationship between flow, turbidity, and temperature at time of downstream migration and subsequent return was evident except that high temperatures and high flows (and turbidities) tended to produce poorer runs during certain time periods; and (16) predation and delay of smolts in reservoirs are largely unknown factors, but circumstantial evidence suggests that they were not important in regulating fall chinook numbers during the period of the study. Finally, variables that appeared to bear some relationship to fluctuations in abundance of fall chinook were submitted to multiple regression analysis. For the predecline period (1938-46 brood years), sea-water temperature and ocean troll fishing effort were significant variables (R² = 0.74). For post decline years (1947-59 broods), troll had the most influence on total return with ocean temperature and escapement having lesser effects. For the combined years, troll intensity and ocean temperature were the significant variables (R² = 0.572). Entering interaction of river flow at downstream migration with the other variables brought R² to 0.754 which means that 75% of the variability in the returning run could be accounted for by these three factors. Return per spawner was so heavily influenced by numbers of spawners that the other factors assumed negligible importance. Equations were derived that predicted the returning run in close agreement with the actual run size. Substituting a low and constant troll fishing effort in the equation resulted in the predicted run maintaining the average predecline level. The increase in ocean fishing was the main contributor to the decline of the Columbia River fall chinook run as shown by correlation, by analogy, and by the process of elimination. To demonstrate why other chinook runs have not shown similar declines, it was shown that due to several unique features in Columbia River fall chinook life history they are exposed to much more ocean fishing than other populations. It was emphasized that these conclusions should not be extrapolated to the future or to other species or runs of salmon. Close

• 39. [Article] Potential Effects of Management on Caspian Tern Hydroprogne caspia Predation on Juvenile Salmonids at a Colony in San Francisco Bay, California

  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 published by Taylor & ...

  Citation × Citation Citation Abstract Copy Title: Potential Effects of Management on Caspian Tern Hydroprogne caspia Predation on Juvenile Salmonids at a Colony in San Francisco Bay, California Author: Evans, Allen F., Adrean, Lindsay J., Roby, Daniel D., Lyons, Donald E., Collis, Ken 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 published by Taylor & Francis and can be found at: http://www.taylorandfrancis.com. Copyrighted by American Fisheries Society (http://afsjournals.org/). Title: Potential Effects of Management on Caspian Tern Hydroprogne caspia Predation on Juvenile Salmonids at a Colony in San Francisco Bay, California Author: Evans, Allen F., Adrean, Lindsay J., Roby, Daniel D., Lyons, Donald E., Collis, Ken 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 published by Taylor & Francis and can be found at: http://www.taylorandfrancis.com. Copyrighted by American Fisheries Society (http://afsjournals.org/). Close

• 40. [Article] Caspian tern (Hydroprogne caspia) foraging ecology and predation on juvenile salmonids in San Francisco Bay, California

  Brooks Island, located in central San Francisco Bay, California, currently supports the largest breeding colony of Caspian terns (Hydroprogne caspia) in the Bay Area, and is one of several proposed relocation ...

  Citation × Citation Citation Abstract Copy Title: Caspian tern (Hydroprogne caspia) foraging ecology and predation on juvenile salmonids in San Francisco Bay, California Author: Adrean, Lindsay J. Brooks Island, located in central San Francisco Bay, California, currently supports the largest breeding colony of Caspian terns (Hydroprogne caspia) in the Bay Area, and is one of several proposed relocation sites for some Caspian terns from the world's largest colony in the Columbia River estuary of Oregon. Juvenile salmonids have been identified in the diet of Caspian terns nesting at Brooks Island, so I investigated whether the colony, at its current or an enhanced size, poses a threat to the recovery of several runs of salmonids (Oncorhynchus spp.) in San Francisco Bay that are listed under the U.S. Endangered Species Act (ESA). I also examined the foraging ecology of Brooks Island Caspian terns to 1) determine whether the colony is suitable for expansion based on availability of forage fish resources, a factor potentially limiting the size and productivity of the colony, and 2) investigate how Caspian terns nesting at this colony exploit forage fish resources. I used a bioenergetics modeling approach, employing estimates of tern energy requirements and proportions of energy supplied by various prey types, to estimate consumption of juvenile salmonids by Caspian terns nesting on Brooks Island during 2008 and 2009. Estimated salmonid consumption was 205,000 smolts (95% CI: 175,000 – 245,000 smolts) in 2008 and 167,000 smolts (95% CI: 144,000 – 191,000 smolts) in 2009. Predation rates on ESA-listed Central Valley spring-run Chinook salmon (O. tshawytscha; 0.08%) were lower than those on unlisted fall-run Chinook salmon (1.0%). Average per capita predation rates on juvenile salmonids by Brooks Island Caspian terns (2008: 126 fish; 2009: 123 fish) were less than half those of Caspian terns nesting in the Columbia River estuary. If the current downward trend in the number of Caspian terns nesting on Brooks Island continues until the colony is no longer extant, the resulting declines in predation on salmonids would lead to increases in annual population growth rates (Δλ) of salmonid runs of just small fractions of one percentage point. The proposed enhancement of the Brooks Island Caspian tern colony to 3,000 individuals would at most cause declines in annual population growth rates of 0.3% for fall-run Chinook salmon and 0.02% for threatened spring-run Chinook salmon, assuming that smolt mortality from tern predation is 100% additive. This level of impact to the ESA-listed spring-run Chinook salmon stock is less than the level considered acceptable by the National Marine Fisheries Service (Δλ = 0.05%). Radio-tracking of Caspian terns nesting on Brooks Island revealed that the maximum foraging distance from the colony was 80 km. The median foraging distance from the colony was greater in 2009 compared to 2008 (20.6 km vs. 14.0 km), average number of foraging trips per day was higher (4.4 vs. 3.4 foraging trips), and average adult colony attendance was lower (43% vs. 52% of daylight hours). These results indicate that the colony was more food-limited during the 2009 breeding season, concurrent with anomalous downwelling along the coast of northern California and reduced availability and size of marine forage fishes, such as herring, sardines, and anchovies. Caspian terns used a number of core foraging areas within 30 km of the Brooks Island colony, both inside and just outside the Bay. Two large core foraging areas were close to or overlapped with the release site for juvenile salmonids in eastern San Pablo Bay, where > 10 million hatchery-raised smolts were released from net pens during both the 2008 and 2009 tern nesting seasons. This finding supports the hypothesis that most juvenile salmonids consumed by terns nesting at the Brooks Island colony were captured at or near the release site. Individual Caspian terns displayed foraging site fidelity, suggesting that foraging at the release site for hatchery-raised salmonids was a learned behavior by some terns. The Brooks Island colony site is within foraging distance of adequate marine forage fish resources in most years, and Caspian terns nesting there are not dependent on juvenile salmonids as a food resource. Consumption of juvenile salmonids by Brooks Island terns would be largely curtailed by modification of hatchery release practices. Title: Caspian tern (Hydroprogne caspia) foraging ecology and predation on juvenile salmonids in San Francisco Bay, California Author: Adrean, Lindsay J. Brooks Island, located in central San Francisco Bay, California, currently supports the largest breeding colony of Caspian terns (Hydroprogne caspia) in the Bay Area, and is one of several proposed relocation sites for some Caspian terns from the world's largest colony in the Columbia River estuary of Oregon. Juvenile salmonids have been identified in the diet of Caspian terns nesting at Brooks Island, so I investigated whether the colony, at its current or an enhanced size, poses a threat to the recovery of several runs of salmonids (Oncorhynchus spp.) in San Francisco Bay that are listed under the U.S. Endangered Species Act (ESA). I also examined the foraging ecology of Brooks Island Caspian terns to 1) determine whether the colony is suitable for expansion based on availability of forage fish resources, a factor potentially limiting the size and productivity of the colony, and 2) investigate how Caspian terns nesting at this colony exploit forage fish resources. I used a bioenergetics modeling approach, employing estimates of tern energy requirements and proportions of energy supplied by various prey types, to estimate consumption of juvenile salmonids by Caspian terns nesting on Brooks Island during 2008 and 2009. Estimated salmonid consumption was 205,000 smolts (95% CI: 175,000 – 245,000 smolts) in 2008 and 167,000 smolts (95% CI: 144,000 – 191,000 smolts) in 2009. Predation rates on ESA-listed Central Valley spring-run Chinook salmon (O. tshawytscha; 0.08%) were lower than those on unlisted fall-run Chinook salmon (1.0%). Average per capita predation rates on juvenile salmonids by Brooks Island Caspian terns (2008: 126 fish; 2009: 123 fish) were less than half those of Caspian terns nesting in the Columbia River estuary. If the current downward trend in the number of Caspian terns nesting on Brooks Island continues until the colony is no longer extant, the resulting declines in predation on salmonids would lead to increases in annual population growth rates (Δλ) of salmonid runs of just small fractions of one percentage point. The proposed enhancement of the Brooks Island Caspian tern colony to 3,000 individuals would at most cause declines in annual population growth rates of 0.3% for fall-run Chinook salmon and 0.02% for threatened spring-run Chinook salmon, assuming that smolt mortality from tern predation is 100% additive. This level of impact to the ESA-listed spring-run Chinook salmon stock is less than the level considered acceptable by the National Marine Fisheries Service (Δλ = 0.05%). Radio-tracking of Caspian terns nesting on Brooks Island revealed that the maximum foraging distance from the colony was 80 km. The median foraging distance from the colony was greater in 2009 compared to 2008 (20.6 km vs. 14.0 km), average number of foraging trips per day was higher (4.4 vs. 3.4 foraging trips), and average adult colony attendance was lower (43% vs. 52% of daylight hours). These results indicate that the colony was more food-limited during the 2009 breeding season, concurrent with anomalous downwelling along the coast of northern California and reduced availability and size of marine forage fishes, such as herring, sardines, and anchovies. Caspian terns used a number of core foraging areas within 30 km of the Brooks Island colony, both inside and just outside the Bay. Two large core foraging areas were close to or overlapped with the release site for juvenile salmonids in eastern San Pablo Bay, where > 10 million hatchery-raised smolts were released from net pens during both the 2008 and 2009 tern nesting seasons. This finding supports the hypothesis that most juvenile salmonids consumed by terns nesting at the Brooks Island colony were captured at or near the release site. Individual Caspian terns displayed foraging site fidelity, suggesting that foraging at the release site for hatchery-raised salmonids was a learned behavior by some terns. The Brooks Island colony site is within foraging distance of adequate marine forage fish resources in most years, and Caspian terns nesting there are not dependent on juvenile salmonids as a food resource. Consumption of juvenile salmonids by Brooks Island terns would be largely curtailed by modification of hatchery release practices. Close