Streaming Media
Presentation Abstract
Estuaries support the reproduction, growth, and survival of Pacific salmon by providing a diverse portfolio of unique habitats with varying physical and biological features. Global climate change is expected to have profound effects on estuarine nursery quality through increasing water temperatures, rising sea levels, and changes in riverine hydrology. We used a spatially explicit bioenergetics model to assess how different climate change and management scenarios might affect juvenile salmon growth relative to present day conditions in the Nisqually River Delta, Washington. The model indicated that reductions in the extent and accessibility of prey-rich habitats such as emergent salt marshes and eelgrass meadows could have severe consequences for salmon growth. For instance, under worst-case sea-level rise scenarios, the predicted extent of emergent salt marsh was reduced by 50%, leading to a corresponding 30% reduction in end-of-season weights. Increasing water temperatures compounded these effects such that the average daily growth rate of an individual fish decreased by an additional 5–50% when compared to the effects of sea-level rise alone. Lethal temperatures (>24 °C) were infrequently observed regardless of model scenario, but temperatures above which salmon can experience nonlethal deleterious effects (>18 °C) became more common in the Delta with climate change. Such thermal limits were most likely to be exceeded during July low tides in the mudflat and eelgrass habitats when accessibility to prey-rich marsh was minimal, thereby limiting foraging capacity and the availability of thermal refugia. Our findings indicate that rising tidal levels and increasing ocean temperatures may reduce estuarine nursery quality for out-migrating salmon and other sensitive fish species if management strategies to mitigate such effects are not enacted.
Session Title
Poster Session 3: Land - Water Connections
Conference Track
SSE14: Posters
Conference Name
Salish Sea Ecosystem Conference (2022 : Online)
Document Type
Event
SSEC Identifier
SSE-posters-69
Start Date
27-4-2022 4:00 PM
End Date
27-4-2022 4:30 PM
Rights
Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this document for commercial purposes, or for financial gain, shall not be allowed without the author's written permission.
Type
Text
Language
English
How will climate change affect estuarine nursery quality? Findings from a spatially explicit bioenergetics model in the Nisqually River Delta
Estuaries support the reproduction, growth, and survival of Pacific salmon by providing a diverse portfolio of unique habitats with varying physical and biological features. Global climate change is expected to have profound effects on estuarine nursery quality through increasing water temperatures, rising sea levels, and changes in riverine hydrology. We used a spatially explicit bioenergetics model to assess how different climate change and management scenarios might affect juvenile salmon growth relative to present day conditions in the Nisqually River Delta, Washington. The model indicated that reductions in the extent and accessibility of prey-rich habitats such as emergent salt marshes and eelgrass meadows could have severe consequences for salmon growth. For instance, under worst-case sea-level rise scenarios, the predicted extent of emergent salt marsh was reduced by 50%, leading to a corresponding 30% reduction in end-of-season weights. Increasing water temperatures compounded these effects such that the average daily growth rate of an individual fish decreased by an additional 5–50% when compared to the effects of sea-level rise alone. Lethal temperatures (>24 °C) were infrequently observed regardless of model scenario, but temperatures above which salmon can experience nonlethal deleterious effects (>18 °C) became more common in the Delta with climate change. Such thermal limits were most likely to be exceeded during July low tides in the mudflat and eelgrass habitats when accessibility to prey-rich marsh was minimal, thereby limiting foraging capacity and the availability of thermal refugia. Our findings indicate that rising tidal levels and increasing ocean temperatures may reduce estuarine nursery quality for out-migrating salmon and other sensitive fish species if management strategies to mitigate such effects are not enacted.
