Recent Salmon Declines: A Result of Lost Feeding Opportunities Due to Bad Timing?

Chittenden, Cedar M.; Jensen, Jenny Lovisa Alexandra; Ewart, David; Anderson, Shannon; Balfry, Shannon K.; Downey, Elan; Eaves, Alexandra A.; Saksida, Sonja; Smith, Brian E.; Vincent, Stephen P.; Welch, David W.; McKinley, R. S.

doi:10.1371/journal.pone.0012423

Cited by 45 publications

(37 citation statements)

References 31 publications

(46 reference statements)

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“…Ample evidence supports the concept that timing of the juvenile migration plays a large role in determining marine survival (Scheuerell et al 2009, Chittenden et al 2010, McMichael et al 2013, and our results provide insight into the underlying mechanisms of this concept. Juvenile fish that migrate early tend to be larger, which may by itself result in higher rates of survival due to size-selective mortality (Zabel and Williams 2002, Duffy and Beauchamp 2011, Woodson et al 2013.…”

Section: Swim Speedsupporting

confidence: 79%

Estimating behavior in a black box: how coastal oceanographic dynamics influence yearling Chinook salmon marine growth and migration behaviors

et al. 2016

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0508-7This version is available at https://strathprints.strath.ac.uk/58466/ Strathprints is designed to allow users to access the research output of the University of Strathclyde. Unless otherwise explicitly stated on the manuscript, Copyright © and Moral Rights for the papers on this site are retained by the individual authors and/or other copyright owners. Please check the manuscript for details of any other licences that may have been applied. You may not engage in further distribution of the material for any profitmaking activities or any commercial gain. You may freely distribute both the url (https://strathprints.strath.ac.uk/) and the content of this paper for research or private study, educational, or not-for-profit purposes without prior permission or charge.Any correspondence concerning this service should be sent to the Strathprints administrator: strathprints@strath.ac.ukThe Strathprints institutional repository (https://strathprints.strath.ac.uk) is a digital archive of University of Strathclyde research outputs. It has been developed to disseminate open access research outputs, expose data about those outputs, and enable the management and persistent access to Strathclyde's intellectual output. AbstractOcean currents or temperature may substantially influence migration behavior in many marine species. However, high-resolution data on animal movement in the marine environment are scarce; therefore, analysts and managers must typically rely on unvalidated assumptions regarding movement, behavior, and habitat use. We used a spatially explicit, individual-based model of early marine migration with two stocks of yearling Chinook salmon to quantify the influence of external forces on estimates of swim speed, consumption, and growth. Model results suggest that salmon behaviorally compensate for changes in the strength and direction of ocean currents. These compensations can result in salmon swimming several times farther than their net movement (straight-line distance) would indicate. However, the magnitude of discrepancy between compensated and straight-line distances varied between oceanographic models. Nevertheless, estimates of relative swim speed among fish groups were less sensitive to the choice of model than estimates of absolute individual swim speed. By comparing groups of fish, this tool can be applied to management questions, such as how experiences and behavior may differ between groups of hatchery fish released early vs. later in the season. By taking into account the experiences and behavior of individual fish, as well as the influence of physical ocean processes, our approach helps illuminate the "black box" of juvenile salmon behavior in the early marine phase of the life cycle.

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Section: Swim Speedsupporting

confidence: 79%

Estimating behavior in a black box: how coastal oceanographic dynamics influence yearling Chinook salmon marine growth and migration behaviors

et al. 2016

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“…The diverging phenological trajectories of zooplankton and many fish species suggests that climate change may lead to an increased frequency of mismatches between trophic levels. During the early life history of fishes, mismatches can result in decreased foraging efficiency, slower growth, starvation, and lower survival (10,34,68). These impacts may eventually lead to poor recruitment, declines in abundance, and even local extinctions (33,69), unless rapid evolution reverses phenological trends or density-dependent compensation occurs at a later life stage (70,71).…”

Section: Discussionmentioning

confidence: 99%

Climate change and decadal shifts in the phenology of larval fishes in the California Current ecosystem

Asch

2015

Proc. Natl. Acad. Sci. U.S.A.

182

139

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Climate change has prompted an earlier arrival of spring in numerous ecosystems. It is uncertain whether such changes are occurring in Eastern Boundary Current Upwelling ecosystems, because these regions are subject to natural decadal climate variability, and regional climate models predict seasonal delays in upwelling. To answer this question, the phenology of 43 species of larval fishes was investigated between 1951 and 2008 off southern California. Ordination of the fish community showed earlier phenological progression in more recent years. Thirty-nine percent of seasonal peaks in larval abundance occurred earlier in the year, whereas 18% were delayed. The species whose phenology became earlier were characterized by an offshore, pelagic distribution, whereas species with delayed phenology were more likely to reside in coastal, demersal habitats. Phenological changes were more closely associated with a trend toward earlier warming of surface waters rather than decadal climate cycles, such as the Pacific Decadal Oscillation and North Pacific Gyre Oscillation. Species with long-term advances and delays in phenology reacted similarly to warming at the interannual time scale as demonstrated by responses to the El Niño Southern Oscillation. The trend toward earlier spawning was correlated with changes in sea surface temperature (SST) and mesozooplankton displacement volume, but not coastal upwelling. SST and upwelling were correlated with delays in fish phenology. For species with 20th century advances in phenology, future projections indicate that current trends will continue unabated. The fate of species with delayed phenology is less clear due to differences between Intergovernmental Panel on Climate Change models in projected upwelling trends.phenology | fish larvae | upwelling ecosystem | California Current | global change biology P henology is the study of seasonal biological processes and how they are influenced by climate and weather. Because warmer temperatures are frequently associated with earlier phenological events, changes in phenology are common indicators of the effects of climate change on ecological communities. Metaanalyses have shown that phenological events have advanced at mean rates of 2-5 d/decade relative to a historical baseline (1-5). Among species for which phenological changes were detected, >80% of these shifts occurred in a direction consistent with climate change (1, 2, 5).Despite the inclusion of hundreds of species in meta-analyses examining climate change effects on phenology, gaps in knowledge persist because most long-term studies of phenology have monitored spring events affecting terrestrial species residing in temperate habitats in the northern hemisphere (2, 4). Marine species are particularly underrepresented in these meta-analyses (6), although see recent work by Poloczanska et al. (5). Underrepresentation of marine species is problematic not only due to their ecological importance, but also because research suggests shifts in phenology may occur more rapidly in marine en...

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“…Year-class strength of walleye pollock has also been associated with variation in zooplankton composition related to phytoplankton phenology (Hunt et al, 2011). Spring bloom dynamics have also been observed to influence recruitment success of Argentine anchovy, Pacific herring, and coho and sockeye salmon (Borstad et al, 2011;Chittenden et al, 2010;Marrari et al, 2013;Schweigert et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Spring bloom dynamics and zooplankton biomass response on the US Northeast Continental Shelf

Friedland

Leaf

Kane

et al. 2015

Continental Shelf Research

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a b s t r a c tThe spring phytoplankton bloom on the US Northeast Continental Shelf is a feature of the ecosystem production cycle that varies annually in timing, spatial extent, and magnitude. To quantify this variability, we analyzed remotely-sensed ocean color data at two spatial scales, one based on ecologically defined sub-units of the ecosystem (production units) and the other on a regular grid (0.5°). Five units were defined: Gulf of Maine East and West, Georges Bank, and Middle Atlantic Bight North and South. The units averaged 47 Â 10 3 km 2 in size. The initiation and termination of the spring bloom were determined using change-point analysis with constraints on what was identified as a bloom based on climatological bloom patterns. A discrete spring bloom was detected in most years over much of the western Gulf of Maine production unit. However, bloom frequency declined in the eastern Gulf of Maine and transitioned to frequencies as low as 50% along the southern flank of the Georges Bank production unit. Detectable spring blooms were episodic in the Middle Atlantic Bight production units. In the western Gulf of Maine, bloom duration was inversely related to bloom start day; thus, early blooms tended to be longer lasting and larger magnitude blooms. We view this as a phenological mismatch between bloom timing and the "top-down" grazing pressure that terminates a bloom. Estimates of secondary production were available from plankton surveys that provided spring indices of zooplankton biovolume. Winter chlorophyll biomass had little effect on spring zooplankton biovolume, whereas spring chlorophyll biomass had mixed effects on biovolume. There was evidence of a "bottom up" response seen on Georges Bank where spring zooplankton biovolume was positively correlated with the concentration of chlorophyll. However, in the western Gulf of Maine, biovolume was uncorrelated with chlorophyll concentration, but was positively correlated with bloom start and negatively correlated with magnitude. This observation is consistent with both a "top-down" mechanism of control of the bloom and a "bottom-up" effect of bloom timing on zooplankton grazing. Our inability to form a consistent model of these relationships across adjacent systems underscores the need for further research.Published by Elsevier Ltd.

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Recent Salmon Declines: A Result of Lost Feeding Opportunities Due to Bad Timing?

Cited by 45 publications

References 31 publications

Estimating behavior in a black box: how coastal oceanographic dynamics influence yearling Chinook salmon marine growth and migration behaviors

Estimating behavior in a black box: how coastal oceanographic dynamics influence yearling Chinook salmon marine growth and migration behaviors

Climate change and decadal shifts in the phenology of larval fishes in the California Current ecosystem

Spring bloom dynamics and zooplankton biomass response on the US Northeast Continental Shelf

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