Details:

Alternative Title:
Estimating fish condition, the relative weight of an individual fish given its body length, is a convenient way to relate the physiological health and energetic status of fishes to their productivity. Despite evidence of density-dependence effects on condition in some species, previous research has not jointly estimated synchronous changes in condition and density operating at fine spatial scales (a few km). Therefore, we developed a spatio-temporal modeling approach that simultaneously estimates correlated variation in density (measured as numbers per area) and condition. We applied our approach to 6 eastern Bering Sea (EBS) groundfish species (4 flatfishes and 2 gadoids) for the period 1992-2016, and estimated correlations in spatial variation (unmeasured variation that is stable over time) and spatio-temporal variation (unmeasured variation that changes between years). Spatial variation in density had a strong significant negative association with spatial variation in condition for 3 flatfishes and a positive association for one gadoid. Spatio-temporal variation in density had a significant association with spatio-temporal variation in condition for one flatfish (negative) and one gadoid (positive). Moreover, for the 6 study species, bottom temperature was identified as an important predictor of both density and condition. The increasing trend in bottom temperatures between 1992 and 2016 was accompanied by an overall increase in the abundance-weighted condition of 5 species. We conclude that forecasts of changes in weight-at-age within some EBS groundfish assessments will require an understanding of both density-dependence and bottom temperature effects on fish condition to better prepare for future climate and exploitation changes.
Journal Title:
Marine Ecology Progress Series
Personal Author:
Gruss, A. ; Gao, J. ; Thorson, J. T. ; Rooper, C. N. ; Thompson, G. ; ... More +
Gruss, A. ; Gao, J. ; Thorson, J. T. ; Rooper, C. N. ; Thompson, G. ; Boldt, J. L. ; Lauth, R. Less -
NOAA Program & Office:
NMFS (National Marine Fisheries Service) ; AFSC (Alaska Fisheries Science Center)
NMFS (National Marine Fisheries Service) ; AFSC (Alaska Fisheries Science Center) Less -
Description:
Estimating fish condition, the relative weight of an individual fish given its body length, is a convenient way to relate the physiological health and energetic status of fishes to their productivity. Despite evidence of density-dependence effects on condition in some species, previous research has not jointly estimated synchronous changes in condition and density operating at fine spatial scales (a few km). Therefore, we developed a spatio-temporal modeling approach that simultaneously estimates correlated variation in density (measured as numbers per area) and condition. We applied our approach to 6 eastern Bering Sea (EBS) groundfish species (4 flatfishes and 2 gadoids) for the period 1992-2016, and estimated correlations in spatial variation (unmeasured variation that is stable over time) and spatio-temporal variation (unmeasured variation that changes between years). Spatial variation in density had a strong significant negative association with spatial variation in condition for 3 flatfishes and a positive association for one gadoid. Spatio-temporal variation in density had a significant association with spatio-temporal variation in condition for one flatfish (negative) and one gadoid (positive). Moreover, for the 6 study species, bottom temperature was identified as an important predictor of both density and condition. The increasing trend in bottom temperatures between 1992 and 2016 was accompanied by an overall increase in the abundance-weighted condition of 5 species. We conclude that forecasts of changes in weight-at-age within some EBS groundfish assessments will require an understanding of both density-dependence and bottom temperature effects on fish condition to better prepare for future climate and exploitation changes.
Keywords:
[+]
Bottom Temperature Effects Density-dependence Eastern Bering Sea Groundfishes Le Cren’s Relative Condition Index Spatiotemporal Models
Source:
Marine Ecology Progress Series, 635, 169-185
DOI:
https://doi.org/10.3354/meps13213
Document Type:
Journal Article
Place as Subject:
Bering Sea
Rights Information:
Accepted Manuscript
Compliance:
Submitted
Main Document Checksum:
[+]
urn:sha256:49750bd438ea08724047a9149d3a3dcdfdf5dad42d89c4265edfe90adb8da43b
Download URL:
https://repository.library.noaa.gov/view/noaa/30023/noaa_30023_DS1.pdf
File Type:

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