Density-Dependent, Trophic Level Responses to an Introduced Run of Sockeye Salmon ( Oncorhynchus nerka ) at Frazer Lake, Kodiak Island, Alaska
Sockeye salmon (Oncorhynchus nerka) have developed into a major run at Frazer Lake, Kodiak Island, Alaska, reaching over 600 000 adults 34 yr after the first egg-plant in 1951. In the last nine years (1978–86), escapements have averaged over 250 000 with a record high of 486 000 adults in 1985. The...
Published in: | Canadian Journal of Fisheries and Aquatic Sciences |
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1988
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Online Access: | http://dx.doi.org/10.1139/f88-104 http://www.nrcresearchpress.com/doi/pdf/10.1139/f88-104 |
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crcansciencepubl:10.1139/f88-104 2024-04-28T08:27:32+00:00 Density-Dependent, Trophic Level Responses to an Introduced Run of Sockeye Salmon ( Oncorhynchus nerka ) at Frazer Lake, Kodiak Island, Alaska Kyle, G. B. Koenings, J. P. Barrett, B. M. 1988 http://dx.doi.org/10.1139/f88-104 http://www.nrcresearchpress.com/doi/pdf/10.1139/f88-104 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Fisheries and Aquatic Sciences volume 45, issue 5, page 856-867 ISSN 0706-652X 1205-7533 Aquatic Science Ecology, Evolution, Behavior and Systematics journal-article 1988 crcansciencepubl https://doi.org/10.1139/f88-104 2024-04-09T06:56:29Z Sockeye salmon (Oncorhynchus nerka) have developed into a major run at Frazer Lake, Kodiak Island, Alaska, reaching over 600 000 adults 34 yr after the first egg-plant in 1951. In the last nine years (1978–86), escapements have averaged over 250 000 with a record high of 486 000 adults in 1985. The increase in escapements were inversely related to seasonal macrozooplankton densities (p < 0.05; r 2 = 0.42) but directly correlated with increases in the cladoceran to copepod ratio (p < 0.001). In addition, the average body length of the smallest macrozooplanker (Bosmina) has shifted below the observed threshold length of 0.40 mm for juvenile sockeye prey. We also found an inverse relationship between greater parental escapements and age 1. smolt length (p < 0.01; r 2 = 0.75). Small-sized smolts produced from a density-dependent rearing environment indicate that spawning capacity equals or exceeds rearing capacity. Juvenile recruits from larger escapements (~400 000) exerted a controlling, density-dependent influence on the secondary trophic level which drastically reduced subsequent adult returns. Moreover, adverse trophic level changes, particularly after the largest escapements, also appeared to reduce the rearing efficiency for lower densities of juveniles, as subsequent smolt sizes from smaller escapements were less than expected. Thus, these findings not only provide a rationale for suggesting that fewer spawners would provide recruits more closely matching the rearing capacity of this lake, but also provide empirical evidence for the potential adverse density-dependent effects of large escapements. Article in Journal/Newspaper Kodiak Alaska Canadian Science Publishing Canadian Journal of Fisheries and Aquatic Sciences 45 5 856 867 |
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Open Polar |
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Canadian Science Publishing |
op_collection_id |
crcansciencepubl |
language |
English |
topic |
Aquatic Science Ecology, Evolution, Behavior and Systematics |
spellingShingle |
Aquatic Science Ecology, Evolution, Behavior and Systematics Kyle, G. B. Koenings, J. P. Barrett, B. M. Density-Dependent, Trophic Level Responses to an Introduced Run of Sockeye Salmon ( Oncorhynchus nerka ) at Frazer Lake, Kodiak Island, Alaska |
topic_facet |
Aquatic Science Ecology, Evolution, Behavior and Systematics |
description |
Sockeye salmon (Oncorhynchus nerka) have developed into a major run at Frazer Lake, Kodiak Island, Alaska, reaching over 600 000 adults 34 yr after the first egg-plant in 1951. In the last nine years (1978–86), escapements have averaged over 250 000 with a record high of 486 000 adults in 1985. The increase in escapements were inversely related to seasonal macrozooplankton densities (p < 0.05; r 2 = 0.42) but directly correlated with increases in the cladoceran to copepod ratio (p < 0.001). In addition, the average body length of the smallest macrozooplanker (Bosmina) has shifted below the observed threshold length of 0.40 mm for juvenile sockeye prey. We also found an inverse relationship between greater parental escapements and age 1. smolt length (p < 0.01; r 2 = 0.75). Small-sized smolts produced from a density-dependent rearing environment indicate that spawning capacity equals or exceeds rearing capacity. Juvenile recruits from larger escapements (~400 000) exerted a controlling, density-dependent influence on the secondary trophic level which drastically reduced subsequent adult returns. Moreover, adverse trophic level changes, particularly after the largest escapements, also appeared to reduce the rearing efficiency for lower densities of juveniles, as subsequent smolt sizes from smaller escapements were less than expected. Thus, these findings not only provide a rationale for suggesting that fewer spawners would provide recruits more closely matching the rearing capacity of this lake, but also provide empirical evidence for the potential adverse density-dependent effects of large escapements. |
format |
Article in Journal/Newspaper |
author |
Kyle, G. B. Koenings, J. P. Barrett, B. M. |
author_facet |
Kyle, G. B. Koenings, J. P. Barrett, B. M. |
author_sort |
Kyle, G. B. |
title |
Density-Dependent, Trophic Level Responses to an Introduced Run of Sockeye Salmon ( Oncorhynchus nerka ) at Frazer Lake, Kodiak Island, Alaska |
title_short |
Density-Dependent, Trophic Level Responses to an Introduced Run of Sockeye Salmon ( Oncorhynchus nerka ) at Frazer Lake, Kodiak Island, Alaska |
title_full |
Density-Dependent, Trophic Level Responses to an Introduced Run of Sockeye Salmon ( Oncorhynchus nerka ) at Frazer Lake, Kodiak Island, Alaska |
title_fullStr |
Density-Dependent, Trophic Level Responses to an Introduced Run of Sockeye Salmon ( Oncorhynchus nerka ) at Frazer Lake, Kodiak Island, Alaska |
title_full_unstemmed |
Density-Dependent, Trophic Level Responses to an Introduced Run of Sockeye Salmon ( Oncorhynchus nerka ) at Frazer Lake, Kodiak Island, Alaska |
title_sort |
density-dependent, trophic level responses to an introduced run of sockeye salmon ( oncorhynchus nerka ) at frazer lake, kodiak island, alaska |
publisher |
Canadian Science Publishing |
publishDate |
1988 |
url |
http://dx.doi.org/10.1139/f88-104 http://www.nrcresearchpress.com/doi/pdf/10.1139/f88-104 |
genre |
Kodiak Alaska |
genre_facet |
Kodiak Alaska |
op_source |
Canadian Journal of Fisheries and Aquatic Sciences volume 45, issue 5, page 856-867 ISSN 0706-652X 1205-7533 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/f88-104 |
container_title |
Canadian Journal of Fisheries and Aquatic Sciences |
container_volume |
45 |
container_issue |
5 |
container_start_page |
856 |
op_container_end_page |
867 |
_version_ |
1797586422230679552 |