Extending statistical age-structured assessment approaches to Gulf of Alaska rockfish (Sebastes spp.)

2007 ◽  
Author(s):  
D.L. Courtney ◽  
J.N. Ianelli ◽  
D. Hanselman ◽  
J. Heifetz
Keyword(s):  
Gulf Of Alaska ◽  
Age Structured

Sensitivity of Optimum Harvest Strategy Estimates to Alternative Definitions of Risk

1994 ◽  
Vol 51 (12) ◽  
pp. 2695-2704 ◽  
Author(s):  
Bernard A. Megrey ◽  
Anne Babcock Hollowed ◽  
Rebecca T. Baldwin
Keyword(s):  
Simulation Model ◽  
Gulf Of Alaska ◽  
Fishing Mortality ◽  
Economic Returns ◽  
The Public ◽  
Public Resource ◽  
Population Dynamics Model ◽  
Age Structured ◽  
Harvest Strategy ◽  
Definition Of

A stochastic age-structured bioeconomic simulation model was developed as a tool for evaluating economic returns to a fishery from alternative harvest policies. The model, which was applied to the Gulf of Alaska walleye pollock (Theragra chalcogramma) fishery, combines the dual goals of protection of the base stock and efficient use of the public resource into an explicit objective function. This paper presents the results of several experiments in which the simulation model is used to examine the sensitivity of the optimum harvest strategy estimates to alternative definitions of risk and assumptions regarding recruitment. Alternative definitions of risk consider assumptions about stock productivity, threshold biomass, economic factors, and hybrid formulations. The bioeconomic extension of the population dynamics model is used to quantify differences in the estimates of optimum fishing mortality obtained from the different risk definitions. Model results demonstrate that estimates of optimal fishing mortality and economic return to the fishery are sensitive to the specific definition of risk used to manage the fishery. The recruitment assumption turned out to be more important to optimum harvest strategy estimates than did risk definitions.

A multispecies age-structured assessment model for the Gulf of Alaska

2010 ◽  
Vol 67 (7) ◽  
pp. 1135-1148 ◽  
Author(s):  
Kray F. Van Kirk ◽  
Terrance J. Quinn ◽  
Jeremy S. Collie
Keyword(s):  
Total Mortality ◽  
Single Species ◽  
Gulf Of Alaska ◽  
Assessment Model ◽  
Proof Of Concept ◽  
Predation Mortality ◽  
Gadus Macrocephalus ◽  
Arrowtooth Flounder ◽  
Age Structured ◽  
Biological Realism

Predation is the largest source of mortality for marine fish and may be an important process in regulating population size. Recent population models have attempted to quantify predation separately from other sources of natural mortality. Building upon such work, a multispecies age-structured assessment model (MSASA) for the Gulf of Alaska was developed, which included arrowtooth flounder ( Atheresthes stomias ), Pacific cod ( Gadus macrocephalus ), and walleye pollock ( Theragra chalcogramma ). Predation mortality was a flexible function of predator and prey abundances that was fitted to stomach-content data. A proof of concept illustration is presented here, assessing model outputs against a set of single-species models. The MSASA model was able to successfully estimate predation between species and integrate it into total mortality. Significant predation occurred on younger pollock and flounder. Results indicate a significant change in predation over time on pollock as a function of increased arrowtooth flounder abundance. Estimating mortality and other parameters for three species simultaneously is complex, and the advantage of greater biological realism of MSASA comes at the expense of greater uncertainty in parameter estimation.

A Three Dimensional Model of the Gulf of Alaska

1987 ◽  
Author(s):  
Shiao-Kung Liu ◽  
Jan J. Leendertse
Keyword(s):  
Three Dimensional ◽  
Gulf Of Alaska ◽  
Dimensional Model ◽  
Three Dimensional Model

Spatial and temporal dynamics of Pacific capelin Mallotus catervarius in the Gulf of Alaska: implications for ecosystem-based fisheries management

2020 ◽  
Vol 637 ◽  
pp. 117-140 ◽  
Author(s):  
DW McGowan ◽  
ED Goldstein ◽  
ML Arimitsu ◽  
AL Deary ◽  
O Ormseth ◽  
...  
Keyword(s):  
Temporal Dynamics ◽  
Marine Ecosystem ◽  
Gulf Of Alaska ◽  
Data Series ◽  
Limited Information ◽  
Important Species ◽  
Multiple Data ◽  
Spatial And Temporal Dynamics ◽  
Spawning Areas ◽  
Spatio Temporal

Pacific capelin Mallotus catervarius are planktivorous small pelagic fish that serve an intermediate trophic role in marine food webs. Due to the lack of a directed fishery or monitoring of capelin in the Northeast Pacific, limited information is available on their distribution and abundance, and how spatio-temporal fluctuations in capelin density affect their availability as prey. To provide information on life history, spatial patterns, and population dynamics of capelin in the Gulf of Alaska (GOA), we modeled distributions of spawning habitat and larval dispersal, and synthesized spatially indexed data from multiple independent sources from 1996 to 2016. Potential capelin spawning areas were broadly distributed across the GOA. Models of larval drift show the GOA’s advective circulation patterns disperse capelin larvae over the continental shelf and upper slope, indicating potential connections between spawning areas and observed offshore distributions that are influenced by the location and timing of spawning. Spatial overlap in composite distributions of larval and age-1+ fish was used to identify core areas where capelin consistently occur and concentrate. Capelin primarily occupy shelf waters near the Kodiak Archipelago, and are patchily distributed across the GOA shelf and inshore waters. Interannual variations in abundance along with spatio-temporal differences in density indicate that the availability of capelin to predators and monitoring surveys is highly variable in the GOA. We demonstrate that the limitations of individual data series can be compensated for by integrating multiple data sources to monitor fluctuations in distributions and abundance trends of an ecologically important species across a large marine ecosystem.

Textural and mineralogical study of sandstones from the onshore Gulf of Alaska Tertiary Province, southern Alaska

1976 ◽  
Author(s):  
Gary R. Winkler ◽  
Hugh McLean ◽  
George Plafker
Keyword(s):  
Gulf Of Alaska ◽  
Mineralogical Study

Bathymetric map of the western Gulf of Alaska

1980 ◽  
Author(s):  
J.M. Dunlavey ◽  
J. R. Childs ◽  
Roland E. von Huene
Keyword(s):  
Gulf Of Alaska ◽  
Bathymetric Map

BENTHIC FORAMINIFERA RECORD THE REPEATED EXPANSION AND INTENSIFICATION OF THE OXYGEN MINIMUM ZONE IN THE GULF OF ALASKA AND ASSOCIATED INCREASES IN PHYTODETRIUS

2018 ◽  
Author(s):  
Christina Belanger ◽  
◽  
Sharon Sharon ◽  
Calie Payne ◽  
Jianghui Du ◽  
...  
Keyword(s):  
Benthic Foraminifera ◽  
Gulf Of Alaska ◽  
Oxygen Minimum Zone ◽  
Minimum Zone ◽  
Oxygen Minimum
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