Do Environmental and Ecological Conditions Explain Declines in Size-at-age of Pacific Halibut in the Gulf of Alaska?

2018 ◽  
Author(s):  
J.Y. Sullivan ◽  
G.H. Kruse ◽  
F.J. Mueter
Keyword(s):  
Gulf Of Alaska ◽  
Ecological Conditions ◽  
Pacific Halibut ◽  
Size At Age

scholarly journals Assessing the relationship between diet and size-at-age in Pacific halibut (Hippoglossus stenolepis) using δ13C and δ15N analysis

2019 ◽  
Vol 76 (12) ◽  
pp. 2326-2331
Author(s):  
Nathan Wolf ◽  
Sarah R. Webster ◽  
Jeffery M. Welker ◽  
Bradley P. Harris
Keyword(s):  
North Pacific Ocean ◽  
Isotope Analysis ◽  
Δ13c And Δ15n ◽  
Pacific Halibut ◽  
Hippoglossus Stenolepis ◽  
Dietary Strategy ◽  
Mean Size ◽  
Intermediate Size ◽  
Size At Age ◽  
The Relationship

The ecological mechanisms driving an observed decline in the mean size-at-age of adult Pacific halibut (Hippoglossus stenolepis) in the eastern North Pacific Ocean have yet to be defined. Here, we present the results of a study designed to investigate the relationship between one potential mechanism — diet — and size-at-age using carbon and nitrogen stable isotope analysis. Our results indicate significant differences in the skeletal muscle δ13C and δ15N values between size-at-age categories for each sex, with larger-size-at-age fish consuming diets with higher δ15N values, indicating higher trophic level feeding. Analysis of Bayesian standard ellipse areas showed that for females, intermediate size-at-age categories have the largest dietary range. For males, the largest dietary range was observed in the largest size-at-age category. Our results suggest a size-based stratification in dietary strategy for Pacific halibut with implications for observed declines in size-at-age.

scholarly journals Comparing the roles of Pacific halibut and arrowtooth flounder within the Gulf of Alaska ecosystem and fishing economy

2019 ◽  
Author(s):  
James J. Ruzicka ◽  
Stephen Kasperski ◽  
Stephani Zador ◽  
Amber Himes‐Cornell
Keyword(s):  
Gulf Of Alaska ◽  
Pacific Halibut ◽  
Arrowtooth Flounder

Age validation of four rockfishes (genera Sebastes and Sebastolobus) with bomb-produced radiocarbon

2020 ◽  
Vol 71 (10) ◽  
pp. 1355
Author(s):  
Craig Kastelle ◽  
Thomas Helser ◽  
Todd TenBrink ◽  
Charles Hutchinson ◽  
Betty Goetz ◽  
...  
Keyword(s):  
Age Determination ◽  
Gulf Of Alaska ◽  
Age Validation ◽  
Pacific Halibut ◽  
The Pacific ◽  
Hippoglossus Stenolepis ◽  
Deep Water Species ◽  
Growth Zones ◽  
Shortspine Thornyhead ◽  
Water Species

In rockfish (Family Scorpaenidae), age determination is difficult and the annual nature of otolith growth zones must be validated independently. We applied routine age determination to four species of Gulf of Alaska rockfish: two shallower-water species, namely harlequin rockfish (Sebastes variegatus) and redstripe rockfish (Sebastes proriger), and two deep-water species, namely shortspine thornyhead (Sebastolobus alascanus) and shortraker rockfish (Sebastes borealis). The estimated ages (counts of presumed annual growth zones in the otoliths) were then evaluated with bomb-produced radiocarbon (14C) and Bayesian modelling with Markov chain Monte Carlo simulations. This study successfully demonstrated the level of accuracy in estimated ages of redstripe rockfish (a 35% probability of underageing, and ~5% probability of overageing) and harlequin rockfish (a 100% probability that they were underaged by ~3 or 4 years). Measured Δ14C in shortspine thornyhead and shortraker rockfish otoliths was lower and increased later than expected. Hence, incorrect age determination could not be evaluated. This is likely caused by dissimilar environmental and biological availability of 14C between these two species and the Pacific halibut (Hippoglossus stenolepis) reference chronology, or underageing of these two species.

A state-space approach for detecting growth variation and application to North Pacific groundfish

2015 ◽  
Vol 72 (9) ◽  
pp. 1316-1328 ◽  
Author(s):  
Christine C. Stawitz ◽  
Timothy E. Essington ◽  
Trevor A. Branch ◽  
Melissa A. Haltuch ◽  
Anne B. Hollowed ◽  
...  
Keyword(s):  
State Space ◽  
Somatic Growth ◽  
Growth Dynamics ◽  
Gulf Of Alaska ◽  
First Year ◽  
State Space Approach ◽  
Growth Variation ◽  
Annual Cohort ◽  
Size At Age ◽  
Space Approach

Understanding demographic variation in recruitment and somatic growth is key to improving our understanding of population dynamics and forecasting ability. Although recruitment variability has been extensively studied, somatic growth variation has received less attention, in part because of difficulties in modeling growth from individual size-at-age estimates. Here we develop a Bayesian state-space approach to test for the prevalence of alternative forms of growth rate variability (e.g., annual, cohort-level, or in the first year recruited to the fishery) in size-at-age data. We apply this technique to 29 Pacific groundfish species across the California Current, Gulf of Alaska, and Bering Sea – Aleutian Islands marine ecosystems. About 40% of modeled stocks were estimated to exhibit temporal growth variation. In the majority of stocks, growth trends fluctuated annually across ages in a single year, suggesting that either there are shared environmental features that dictate growth across multiple ages or the presence of some systematic (within-year) observation errors. This method represents a novel way to use size-at-age data from fishery or other sources to test hypotheses about growth dynamics variability.

Climate effects and bottom‐up controls on growth and size‐at‐age of Pacific halibut (Hippoglossus stenolepis) in Alaska (USA)

2018 ◽  
Vol 28 (3) ◽  
pp. 345-358 ◽  
Author(s):  
Kirstin K. Holsman ◽  
Kerim Aydin ◽  
Jane Sullivan ◽  
Tom Hurst ◽  
Gordon H. Kruse
Keyword(s):  
Bottom Up ◽  
Climate Effects ◽  
Pacific Halibut ◽  
Hippoglossus Stenolepis ◽  
Size At Age

Multiple life‐stage connectivity of Pacific halibut ( Hippoglossus stenolepis ) across the Bering Sea and Gulf of Alaska

2020 ◽  
Author(s):  
Lauri L. Sadorus ◽  
Esther D. Goldstein ◽  
Raymond A. Webster ◽  
William T. Stockhausen ◽  
Josep V. Planas ◽  
...  
Keyword(s):  
Bering Sea ◽  
Life Stage ◽  
Gulf Of Alaska ◽  
Pacific Halibut ◽  
Hippoglossus Stenolepis ◽  
The Bering Sea

Spatial Distribution of Pacific Halibut (Hippoglossus stenolepis): An Application of Geostatistics to Longline Survey Data

1994 ◽  
Vol 51 (7) ◽  
pp. 1506-1518 ◽  
Author(s):  
Dominique Pelletier ◽  
Ana M. Parma
Keyword(s):  
Spatial Distribution ◽  
Spatial Structure ◽  
Large Scale ◽  
Survey Design ◽  
Gulf Of Alaska ◽  
Small Scale ◽  
Spatially Correlated ◽  
Pacific Halibut ◽  
Hippoglossus Stenolepis ◽  
Geostatistical Techniques

The spatial distribution of Pacific halibut (Hippoglossus stenolepis) in the Gulf of Alaska was analyzed using longline catch per unit of effort (CPUE) data collected during three grid surveys in 1984, 1985, and 1986. Geostatistical techniques were used: (i) a variographic analysis to model and estimate the spatial structure of halibut abundance and (ii) ordinary kriging to predict local abundance. Available small-scale information made it possible to model satisfactorily the spatial structure. Results show (i) a persistent large-scale east–west difference in average CPUE and (ii) spatially correlated CPUE data with an average covariance decreasing as the distance between observations increased, over a range of 0–20 nautical miles (nmi) in 1984 and 1985, and 50 nmi in 1986. The survey design had limitations in that it was too unbalanced, with stations very close together along north–south transects, and transects too far apart from each other. Consequently, prediction error was small close to the transects and large in between in a clear banded pattern. To achieve a more regular coverage of the same area, a new survey design was developed: the global variances obtained with this new design using the variogram parameters for 1985 and 1986 were 20% lower than those based on the old design.

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