Brood tables, also called run reconstructions, utilize annual estimates of the total run (commerc... more Brood tables, also called run reconstructions, utilize annual estimates of the total run (commercial catch plus escapement), and samples of ages, to estimate the number of recruits per age class. These data are useful for salmon biologists to understand salmon productivity and salmon life histories. These data can come in a number of different formats, but generally follow the pattern of: rows for each brood year, and columns for the estimated number of fish in each age class. This dataset consists of reformated and merged brood tables from Alaska, British Columbia, and Washington. These datasets were gathered as part of the State of Alaskan Salmon and People project (https://alaskasalmonandpeople.org/). Source information for the datasets can be found in the SourceInfo.csv file. A description of the merging and quality assurance process can be found in the broodTableProcessing.html file. Productivity (R/S) should not be directly compared among the stocks because some escapement cou...
North American Journal of Fisheries Management, 1992
Abstract.The consumption of recently emerged sockeye salmon Oncorhynchus nerka by ju-venile coho... more Abstract.The consumption of recently emerged sockeye salmon Oncorhynchus nerka by ju-venile coho salmon O. kisutch in Chignik Lake, Alaska, was estimated for 15 May-5 August, 1985-1987. Estimated daily consumption of sockeye salmon fry by individual ...
... al]). Observations of density-dependent growth of sockeye salmon in lakes ([Burgner, 1987 and... more ... al]). Observations of density-dependent growth of sockeye salmon in lakes ([Burgner, 1987 and Bugaev et al]) are important because larger juvenile salmon typically experience higher survival at sea ( [Koenings et al]). Past ...
Gastric evacuation of multiple meals of recently emerged sockeye salmon, Oncorhynchus nerka, cons... more Gastric evacuation of multiple meals of recently emerged sockeye salmon, Oncorhynchus nerka, consumed by juvenile coho salmon, O. kisutch, were compared with that expected from a single meal evacuation rate model developed for the estimation of food consumption by coho in the field. Significant interaction occurred between meals consumed two hours apart (p<0.001). Evacuation of the first of two meals
Increasing production of hatchery salmon over the past four decades has led to concerns about pos... more Increasing production of hatchery salmon over the past four decades has led to concerns about possible density-dependent effects on wild Pacific salmon populations in the North Pacific Ocean. The concern arises because salmon from distant regions overlap in the ocean, and wild salmon populations having low productivity may compete for food with abundant hatchery populations. We tested the hypothesis that adult length-at-age, age-at-maturation, productivity, and abundance of a Norton Sound, Alaska, chum salmon population were influenced by Asian hatchery chum salmon, which have become exceptionally abundant and surpassed the abundance of wild chum salmon in the North Pacific beginning in the early 1980s. We found that smaller adult length-at-age, delayed age-at-maturation, and reduced productivity and abundance of the Norton Sound salmon population were associated with greater production of Asian hatchery chum salmon since 1965. Modeling of the density-dependent relationship, while controlling for other influential variables, indicated that an increase in adult hatchery chum salmon abundance from 10 million to 80 million adult fish led to a 72% reduction in the abundance of the wild chum salmon population. These findings indicate that competition with hatchery chum salmon contributed to the low productivity and abundance of Norton Sound chum salmon, which includes several stocks that are classified as Stocks of Concern by the State of Alaska. This study provides new evidence indicating that large-scale hatchery production may influence body size, age-at-maturation, productivity and abundance of a distant wild salmon population.
The importance of interspecific competition as a mechanism regulating population abundance in off... more The importance of interspecific competition as a mechanism regulating population abundance in offshore marine communities is largely unknown. We evaluated offshore competition between Asian pink salmon and Bristol Bay (Alaska) sockeye salmon, which intermingle in the North Pacific Ocean and Bering Sea, using the unique biennial abundance cycle of Asian pink salmon from 1955 to 2000. Sockeye salmon growth during the second and third growing seasons at sea, as determined by scale measurements, declined significantly in odd-numbered years, corresponding to years when Asian pink salmon are most abundant. Bristol Bay sockeye salmon do not interact with Asian pink salmon during their first summer and fall seasons and no difference in first year scale growth was detected. The interaction with odd-year pink salmon led to significantly smaller size at age of adult sockeye salmon, especially among younger female salmon. Examination of sockeye salmon smolt to adult survival rates during 1977-97 indicated that smolts entering the ocean during even-numbered years and interacting with abundant odd-year pink salmon during the following year experienced 26% (age-2 smolt) to 45% (age-1 smolt) lower survival compared with smolts migrating during odd-numbered years. Adult sockeye salmon returning to Bristol Bay from evenyear smolt migrations were 22% less abundant (reduced by 5.9 million fish per year) compared with returns from odd-year migrations. The greatest reduction in adult returns occurred among adults spending 2 compared with 3 years at sea. Our new evidence for interspecific competition highlights the need for multispecies, international management of salmon production, including salmon released from hatcheries into the ocean.
Proceedings of the National Academy of Sciences, 2012
Well-functioning food webs are fundamental for sustaining rivers as ecosystems and maintaining as... more Well-functioning food webs are fundamental for sustaining rivers as ecosystems and maintaining associated aquatic and terrestrial communities. The current emphasis on restoring habitat structure—without explicitly considering food webs—has been less successful than hoped in terms of enhancing the status of targeted species and often overlooks important constraints on ecologically effective restoration. We identify three priority food web-related issues that potentially impede successful river restoration: uncertainty about habitat carrying capacity, proliferation of chemicals and contaminants, and emergence of hybrid food webs containing a mixture of native and invasive species. Additionally, there is the need to place these food web considerations in a broad temporal and spatial framework by understanding the consequences of altered nutrient, organic matter (energy), water, and thermal sources and flows, reconnecting critical habitats and their food webs, and restoring for changing...
Abundance estimates of wild and hatchery Pacific salmon Oncorhynchus spp. are important for evalu... more Abundance estimates of wild and hatchery Pacific salmon Oncorhynchus spp. are important for evaluation of stock status and density-dependent interactions at sea. This data package includes total abundances of pink, chum, and sockeye salmon, reconstructed from catch and spawning abundance data for both Asia and North America. These data are in two main categories of salmon abundance estimates: (1) return (catch plus escapement) estimates of natural-origin and enhanced-origin salmon (numerical and biomass) by species and region, and (2) Total biomass estimates of mature and younger salmon by species and region (natural-origin and hatchery-origin combined). Most of the tables cover the period from 1952-2015. Longterm tables begin at 1925. The .csv files are plain text versions of the tables found in the original excel file. The excel file also contains additional information on how the datasets can be used. These data are described further in: Ruggerone, G.T., Peterman, R.M., Dorner, B...
Many biological, hydrological, and geological processes are interactively linked in ecosystems. T... more Many biological, hydrological, and geological processes are interactively linked in ecosystems. These ecological phenomena normally vary within bounded ranges, but rapid, nonlinear changes to markedly different conditions can be triggered by even small differences if threshold values are exceeded. Intrinsic and extrinsic ecological thresholds can lead to effects that cascade among systems, precluding accurate modeling and prediction of system response to climate change. Ten case studies from North America illustrate how changes in climate can lead to rapid, threshold-type responses within ecological communities; the case studies also highlight the role of human activities that alter the rate or direction of system response to climate change.
Brood tables, also called run reconstructions, utilize annual estimates of the total run (commerc... more Brood tables, also called run reconstructions, utilize annual estimates of the total run (commercial catch plus escapement), and samples of ages, to estimate the number of recruits per age class. These data are useful for salmon biologists to understand salmon productivity and salmon life histories. These data can come in a number of different formats, but generally follow the pattern of: rows for each brood year, and columns for the estimated number of fish in each age class. This dataset consists of reformated and merged brood tables from Alaska, British Columbia, and Washington. These datasets were gathered as part of the State of Alaskan Salmon and People project (https://alaskasalmonandpeople.org/). Source information for the datasets can be found in the SourceInfo.csv file. A description of the merging and quality assurance process can be found in the broodTableProcessing.html file. Productivity (R/S) should not be directly compared among the stocks because some escapement cou...
North American Journal of Fisheries Management, 1992
Abstract.The consumption of recently emerged sockeye salmon Oncorhynchus nerka by ju-venile coho... more Abstract.The consumption of recently emerged sockeye salmon Oncorhynchus nerka by ju-venile coho salmon O. kisutch in Chignik Lake, Alaska, was estimated for 15 May-5 August, 1985-1987. Estimated daily consumption of sockeye salmon fry by individual ...
... al]). Observations of density-dependent growth of sockeye salmon in lakes ([Burgner, 1987 and... more ... al]). Observations of density-dependent growth of sockeye salmon in lakes ([Burgner, 1987 and Bugaev et al]) are important because larger juvenile salmon typically experience higher survival at sea ( [Koenings et al]). Past ...
Gastric evacuation of multiple meals of recently emerged sockeye salmon, Oncorhynchus nerka, cons... more Gastric evacuation of multiple meals of recently emerged sockeye salmon, Oncorhynchus nerka, consumed by juvenile coho salmon, O. kisutch, were compared with that expected from a single meal evacuation rate model developed for the estimation of food consumption by coho in the field. Significant interaction occurred between meals consumed two hours apart (p<0.001). Evacuation of the first of two meals
Increasing production of hatchery salmon over the past four decades has led to concerns about pos... more Increasing production of hatchery salmon over the past four decades has led to concerns about possible density-dependent effects on wild Pacific salmon populations in the North Pacific Ocean. The concern arises because salmon from distant regions overlap in the ocean, and wild salmon populations having low productivity may compete for food with abundant hatchery populations. We tested the hypothesis that adult length-at-age, age-at-maturation, productivity, and abundance of a Norton Sound, Alaska, chum salmon population were influenced by Asian hatchery chum salmon, which have become exceptionally abundant and surpassed the abundance of wild chum salmon in the North Pacific beginning in the early 1980s. We found that smaller adult length-at-age, delayed age-at-maturation, and reduced productivity and abundance of the Norton Sound salmon population were associated with greater production of Asian hatchery chum salmon since 1965. Modeling of the density-dependent relationship, while controlling for other influential variables, indicated that an increase in adult hatchery chum salmon abundance from 10 million to 80 million adult fish led to a 72% reduction in the abundance of the wild chum salmon population. These findings indicate that competition with hatchery chum salmon contributed to the low productivity and abundance of Norton Sound chum salmon, which includes several stocks that are classified as Stocks of Concern by the State of Alaska. This study provides new evidence indicating that large-scale hatchery production may influence body size, age-at-maturation, productivity and abundance of a distant wild salmon population.
The importance of interspecific competition as a mechanism regulating population abundance in off... more The importance of interspecific competition as a mechanism regulating population abundance in offshore marine communities is largely unknown. We evaluated offshore competition between Asian pink salmon and Bristol Bay (Alaska) sockeye salmon, which intermingle in the North Pacific Ocean and Bering Sea, using the unique biennial abundance cycle of Asian pink salmon from 1955 to 2000. Sockeye salmon growth during the second and third growing seasons at sea, as determined by scale measurements, declined significantly in odd-numbered years, corresponding to years when Asian pink salmon are most abundant. Bristol Bay sockeye salmon do not interact with Asian pink salmon during their first summer and fall seasons and no difference in first year scale growth was detected. The interaction with odd-year pink salmon led to significantly smaller size at age of adult sockeye salmon, especially among younger female salmon. Examination of sockeye salmon smolt to adult survival rates during 1977-97 indicated that smolts entering the ocean during even-numbered years and interacting with abundant odd-year pink salmon during the following year experienced 26% (age-2 smolt) to 45% (age-1 smolt) lower survival compared with smolts migrating during odd-numbered years. Adult sockeye salmon returning to Bristol Bay from evenyear smolt migrations were 22% less abundant (reduced by 5.9 million fish per year) compared with returns from odd-year migrations. The greatest reduction in adult returns occurred among adults spending 2 compared with 3 years at sea. Our new evidence for interspecific competition highlights the need for multispecies, international management of salmon production, including salmon released from hatcheries into the ocean.
Proceedings of the National Academy of Sciences, 2012
Well-functioning food webs are fundamental for sustaining rivers as ecosystems and maintaining as... more Well-functioning food webs are fundamental for sustaining rivers as ecosystems and maintaining associated aquatic and terrestrial communities. The current emphasis on restoring habitat structure—without explicitly considering food webs—has been less successful than hoped in terms of enhancing the status of targeted species and often overlooks important constraints on ecologically effective restoration. We identify three priority food web-related issues that potentially impede successful river restoration: uncertainty about habitat carrying capacity, proliferation of chemicals and contaminants, and emergence of hybrid food webs containing a mixture of native and invasive species. Additionally, there is the need to place these food web considerations in a broad temporal and spatial framework by understanding the consequences of altered nutrient, organic matter (energy), water, and thermal sources and flows, reconnecting critical habitats and their food webs, and restoring for changing...
Abundance estimates of wild and hatchery Pacific salmon Oncorhynchus spp. are important for evalu... more Abundance estimates of wild and hatchery Pacific salmon Oncorhynchus spp. are important for evaluation of stock status and density-dependent interactions at sea. This data package includes total abundances of pink, chum, and sockeye salmon, reconstructed from catch and spawning abundance data for both Asia and North America. These data are in two main categories of salmon abundance estimates: (1) return (catch plus escapement) estimates of natural-origin and enhanced-origin salmon (numerical and biomass) by species and region, and (2) Total biomass estimates of mature and younger salmon by species and region (natural-origin and hatchery-origin combined). Most of the tables cover the period from 1952-2015. Longterm tables begin at 1925. The .csv files are plain text versions of the tables found in the original excel file. The excel file also contains additional information on how the datasets can be used. These data are described further in: Ruggerone, G.T., Peterman, R.M., Dorner, B...
Many biological, hydrological, and geological processes are interactively linked in ecosystems. T... more Many biological, hydrological, and geological processes are interactively linked in ecosystems. These ecological phenomena normally vary within bounded ranges, but rapid, nonlinear changes to markedly different conditions can be triggered by even small differences if threshold values are exceeded. Intrinsic and extrinsic ecological thresholds can lead to effects that cascade among systems, precluding accurate modeling and prediction of system response to climate change. Ten case studies from North America illustrate how changes in climate can lead to rapid, threshold-type responses within ecological communities; the case studies also highlight the role of human activities that alter the rate or direction of system response to climate change.
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Papers by Greg Ruggerone