Documentation of en route mortality of summer chum salmon in the Koyukuk River, Alaska and its potential linkage to the heatwave of 2019
This paper and associated dataset documents a mass en route mortality event of adult summer chum salmon (Oncorhynchus keta) returning to the Koyukuk River, Alaska in the Yukon River basin. In response to reports from local communities, a small team of researchers (including the author) surveyed ca....
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Knowledge Network for Biocomplexity
2020
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dataone:urn:uuid:00862788-702c-4053-bf9b-c96b188ee1bf 2023-11-08T14:15:00+01:00 Documentation of en route mortality of summer chum salmon in the Koyukuk River, Alaska and its potential linkage to the heatwave of 2019 Peter Westley Koyukuk River, Alaska ENVELOPE(-154.28,-154.28,66.05,66.05) BEGINDATE: 2019-01-01T00:00:00Z ENDDATE: 2020-01-01T00:00:00Z 2020-01-01T00:00:00Z https://search.dataone.org/view/urn:uuid:00862788-702c-4053-bf9b-c96b188ee1bf unknown Knowledge Network for Biocomplexity Migration Pacific salmon Prespawning mortality Alaska Global warming 2019 Heatwave Oncorhynchus keta Dataset 2020 dataone:urn:node:KNB 2023-11-08T13:46:16Z This paper and associated dataset documents a mass en route mortality event of adult summer chum salmon (Oncorhynchus keta) returning to the Koyukuk River, Alaska in the Yukon River basin. In response to reports from local communities, a small team of researchers (including the author) surveyed ca. 275 km of river on July 26 and 27, 2019 and counted 1,364 dead salmon. Although the total magnitude of mortality is unknown, counts from the survey certainly represent only a small fraction of the true number of fish that died. We sampled 73 carcasses to confirm death occurred prematurely prior to complete maturation and spawning, and to quantify sex and length. Visual inspection revealed a substantial fraction exhibited patterns of fungal growth consistent with secondary infections of skin lesions caused by the ubiquitous natural bacterial pathogen Flavobacterium columnare. Water temperatures during the survey averaged 17.1°C and the water was approximately 85% saturated with oxygen (ca. 8.5 mg/L), which likely contributed to the stress for upstream migrants. Evidence suggests size-selective en route mortality as female migrants that died were 2% and male migrants 5% shorter than individuals that survived to their spawning grounds on Henshaw Creek. This translates to very strong estimates of natural selection using standardized selection differentials, yet it is unclear whether selection acts on body size directly or indirectly through correlated phenotypic traits such as run timing. The mortality event likely underpins the below average returns of summer chum salmon to the Koyukuk River in 2019, suggesting an impact on spawner abundance. The future consequences of this, or potentially increasingly frequent, en route mortality events for population productivity and the extent to which genetic adaptation or adaptive phenotypic plasticity of migration behavior may facilitate persistence of these populations is unknown. Dataset Yukon river Alaska Yukon Knowledge Network for Biocomplexity (via DataONE) Keta ENVELOPE(-19.455,-19.455,65.656,65.656) Pacific Yukon ENVELOPE(-154.28,-154.28,66.05,66.05) |
institution |
Open Polar |
collection |
Knowledge Network for Biocomplexity (via DataONE) |
op_collection_id |
dataone:urn:node:KNB |
language |
unknown |
topic |
Migration Pacific salmon Prespawning mortality Alaska Global warming 2019 Heatwave Oncorhynchus keta |
spellingShingle |
Migration Pacific salmon Prespawning mortality Alaska Global warming 2019 Heatwave Oncorhynchus keta Peter Westley Documentation of en route mortality of summer chum salmon in the Koyukuk River, Alaska and its potential linkage to the heatwave of 2019 |
topic_facet |
Migration Pacific salmon Prespawning mortality Alaska Global warming 2019 Heatwave Oncorhynchus keta |
description |
This paper and associated dataset documents a mass en route mortality event of adult summer chum salmon (Oncorhynchus keta) returning to the Koyukuk River, Alaska in the Yukon River basin. In response to reports from local communities, a small team of researchers (including the author) surveyed ca. 275 km of river on July 26 and 27, 2019 and counted 1,364 dead salmon. Although the total magnitude of mortality is unknown, counts from the survey certainly represent only a small fraction of the true number of fish that died. We sampled 73 carcasses to confirm death occurred prematurely prior to complete maturation and spawning, and to quantify sex and length. Visual inspection revealed a substantial fraction exhibited patterns of fungal growth consistent with secondary infections of skin lesions caused by the ubiquitous natural bacterial pathogen Flavobacterium columnare. Water temperatures during the survey averaged 17.1°C and the water was approximately 85% saturated with oxygen (ca. 8.5 mg/L), which likely contributed to the stress for upstream migrants. Evidence suggests size-selective en route mortality as female migrants that died were 2% and male migrants 5% shorter than individuals that survived to their spawning grounds on Henshaw Creek. This translates to very strong estimates of natural selection using standardized selection differentials, yet it is unclear whether selection acts on body size directly or indirectly through correlated phenotypic traits such as run timing. The mortality event likely underpins the below average returns of summer chum salmon to the Koyukuk River in 2019, suggesting an impact on spawner abundance. The future consequences of this, or potentially increasingly frequent, en route mortality events for population productivity and the extent to which genetic adaptation or adaptive phenotypic plasticity of migration behavior may facilitate persistence of these populations is unknown. |
format |
Dataset |
author |
Peter Westley |
author_facet |
Peter Westley |
author_sort |
Peter Westley |
title |
Documentation of en route mortality of summer chum salmon in the Koyukuk River, Alaska and its potential linkage to the heatwave of 2019 |
title_short |
Documentation of en route mortality of summer chum salmon in the Koyukuk River, Alaska and its potential linkage to the heatwave of 2019 |
title_full |
Documentation of en route mortality of summer chum salmon in the Koyukuk River, Alaska and its potential linkage to the heatwave of 2019 |
title_fullStr |
Documentation of en route mortality of summer chum salmon in the Koyukuk River, Alaska and its potential linkage to the heatwave of 2019 |
title_full_unstemmed |
Documentation of en route mortality of summer chum salmon in the Koyukuk River, Alaska and its potential linkage to the heatwave of 2019 |
title_sort |
documentation of en route mortality of summer chum salmon in the koyukuk river, alaska and its potential linkage to the heatwave of 2019 |
publisher |
Knowledge Network for Biocomplexity |
publishDate |
2020 |
url |
https://search.dataone.org/view/urn:uuid:00862788-702c-4053-bf9b-c96b188ee1bf |
op_coverage |
Koyukuk River, Alaska ENVELOPE(-154.28,-154.28,66.05,66.05) BEGINDATE: 2019-01-01T00:00:00Z ENDDATE: 2020-01-01T00:00:00Z |
long_lat |
ENVELOPE(-19.455,-19.455,65.656,65.656) ENVELOPE(-154.28,-154.28,66.05,66.05) |
geographic |
Keta Pacific Yukon |
geographic_facet |
Keta Pacific Yukon |
genre |
Yukon river Alaska Yukon |
genre_facet |
Yukon river Alaska Yukon |
_version_ |
1782011836035497984 |