A mixed-species yield model for eastern Bering Sea shelf flatfish fisheries

2002 ◽  
Vol 59 (2) ◽  
pp. 291-302 ◽  
Author(s):  
Paul D Spencer ◽  
Thomas K Wilderbuer ◽  
Chang Ik Zhang
Keyword(s):  
Bering Sea ◽  
Optimal Solution ◽  
Single Species ◽  
Mixed Species ◽  
Yield Model ◽  
Pacific Halibut ◽  
Eastern Bering Sea ◽  
Hippoglossus Stenolepis ◽  
Hippoglossoides Elassodon ◽  
Trawl Fisheries

A variety of eastern Bering Sea (EBS) flatfish including yellowfin sole (Limanda aspera), rock sole (Lepidopsetta bilineata), flathead sole (Hippoglossoides elassodon), and Alaska plaice (Pleuronectes quadrituberculatus), co-occur in various degrees in EBS trawl fisheries, impeding attempts to obtain single-species management targets. A further complication is the bycatch of Pacific halibut (Hippoglossus stenolepis); halibut bycatch limits, rather than single-species catch quotas, have been the primary factor regulating EBS flatfish harvest in recent years. To examine bycatch interactions among the EBS flatfish listed above, an equilibrium mixed-species multifishery model was developed. Equilibrium yield curves, scaled by recent average recruitment, are flat topped or asymptotically increasing, reflecting low fishing selectivity during the first several years of life and low growth relative to natural mortality. A linear programming analysis indicated that relaxation of the halibut bycatch constraint at the optimal solution of catch by fishery would produce approximately 20 times more flatfish yield than a similar relaxation of any flatfish catch quota. A strategy for establishing halibut bycatch limits that considers the foregone revenue in the halibut and flatfish trawl fisheries reveals how the choice of halibut bycatch limit is affected by the management goal for the flatfish complex.

Serum Transferrin Systems and the Hemoglobins of the Pacific Halibut (Hippoglossus stenolepis)

1969 ◽  
Vol 26 (9) ◽  
pp. 2351-2362 ◽  
Author(s):  
H. Tsuyuki ◽  
E. Roberts ◽  
E. A. Best
Keyword(s):  
Bering Sea ◽  
Serum Proteins ◽  
Rare Type ◽  
Population Analyses ◽  
Pacific Halibut ◽  
Eastern Bering Sea ◽  
The Pacific ◽  
Hippoglossus Stenolepis ◽  
Northeastern Pacific ◽  
Starch Gel

Based on starch-gel electrophoretic analyses of serum proteins of 1092 specimens of Pacific halibut sampled from the eastern Bering Sea and northeastern Pacific Ocean southward to southern British Columbia, three molecular species of transferrins were encountered. A fourth rare type was postulated to explain the observation of some phenotypes involving this transferrin. These transferrins, either singly or in combinations of two, accounted for the theoretically possible 10 phenotypes of which 8 were actually observed. Hereditary control by four codominant alleles (TfA, TfB, TfC, and TfD) is postulated to explain the heterogeneity of the transferrin patterns. The collections were arbitrarily divided into 10 geographic areas and gene frequency analyses were used to determine population structure. Phenotypic distribution was shown to be independent of age and sex. Of the 10 areas, only the collection from southeastern Alaska proved not to be homogeneous. Preliminary analysis of blood hemoglobins indicated that these proteins are not of value in population analyses.

scholarly journals Comparison of the biophysical and trophic characteristics of the Bering and Barents Seas

2005 ◽  
Vol 62 (7) ◽  
pp. 1245-1255 ◽  
Author(s):  
George L. Hunt ◽  
Bernard A. Megrey
Keyword(s):  
Bering Sea ◽  
Barents Sea ◽  
Single Species ◽  
Atlantic Water ◽  
Walleye Pollock ◽  
Fish Stocks ◽  
Eastern Bering Sea ◽  
The Barents Sea ◽  
Shelf Seas ◽  
Bottom Waters

Abstract The eastern Bering Sea and the Barents Sea share a number of common biophysical characteristics. For example, both are seasonally ice-covered, high-latitude, shelf seas, dependent on advection for heat and for replenishment of nutrients on their shelves, and with ecosystems dominated by a single species of gadoid fish. At the same time, they differ in important respects. In the Barents Sea, advection of Atlantic Water is important for zooplankton vital to the Barents Sea productivity. Advection of zooplankton is not as important for the ecosystems of the southeastern Bering Sea, where high levels of diatom production can support production of small, neritic zooplankton. In the Barents Sea, cod are the dominant gadoid, and juvenile and older fish depend on capelin and other forage fish to repackage the energy available in copepods. In contrast, the dominant fish in the eastern Bering Sea is the walleye pollock, juveniles and adults of which consume zooplankton directly. The southeastern Bering Sea supports considerably larger fish stocks than the Barents. In part, this may reflect the greater depth of much of the Barents Sea compared with the shallow shelf of the southeastern Bering. However, walleye pollock is estimated to occupy a trophic level of 3.3 as compared to 4.3 for Barents Sea cod. This difference alone could have a major impact on the abilities of these seas to support a large biomass of gadoids. In both seas, climate-forced variability in advection and sea-ice cover can potentially have major effects on the productivity of these Subarctic seas. In the Bering Sea, the size and location of pools of cold bottom waters on the shelf may influence the likelihood of predation of juvenile pollock.

Survival outcome patterns revealed by deploying advanced tags in quantity: Pacific halibut (Hippoglossus stenolepis) survivals after release from trawl catches through expedited sorting

2019 ◽  
Vol 76 (12) ◽  
pp. 2215-2224 ◽  
Author(s):  
Craig S. Rose ◽  
Julie K. Nielsen ◽  
John R. Gauvin ◽  
Timothy Loher ◽  
Suresh A. Sethi ◽  
...  
Keyword(s):  
Survival Rates ◽  
Estimation Methods ◽  
Fish Length ◽  
Air Exposure ◽  
Pacific Halibut ◽  
Archival Tags ◽  
Hippoglossus Stenolepis ◽  
Survival Estimation ◽  
Survival Differences ◽  
Trawl Fisheries

Bycatch of Pacific halibut (Hippoglossus stenolepis) limits many trawl fisheries in Alaska and greatly concerns stakeholders from local communities and fisheries that rely on Pacific halibut. To reduce Pacific halibut mortality, trawlers in the Bering Sea that target flatfish have been developing expedited release procedures to sort Pacific halibut from catches earlier than current regulations allow, while continuing accurate bycatch accounting. We studied survival rates of released Pacific halibut from three trawlers by deploying accelerometer-equipped pop-up satellite archival tags (PSATs) on 160 fish handled under expedited procedures. PSATs recorded and transmitted two metrics indicating swimming activity every 2 h while attached to the fish (for up to 60 days). Analysis of the resulting survival outcomes largely validated current survival-estimation methods, based on structured viability assessments, and found that longer fish length, shorter duration of air exposure, and shorter duration of trawl tow improved predicted Pacific halibut survival. Differences in these results were detected among vessel trips and species targeted by trawling. PSATs provided detailed data from nearly all tagged fish, while exposing fish to conditions experienced by normal releases.

scholarly journals Changes in habitat utilization of slope-spawning flatfish across a bathymetric gradient

2016 ◽  
Vol 73 (7) ◽  
pp. 1875-1889 ◽  
Author(s):  
Cathleen D. Vestfals ◽  
Lorenzo Ciannelli ◽  
Gerald R. Hoff
Keyword(s):  
Habitat Use ◽  
Environmental Variability ◽  
Effect Of Temperature ◽  
Greenland Halibut ◽  
Pacific Halibut ◽  
Eastern Bering Sea ◽  
Geographic Coverage ◽  
Hippoglossus Stenolepis ◽  
Greenland Halibut Reinhardtius Hippoglossoides ◽  
Ocean Environment

Abstract Understanding how fish distributions may change in response to environmental variability is important for effective management of fish populations, as predicted climate change will likely alter their habitat use and population dynamics. This research focused on two commercially- and ecologically-important flatfish species in the eastern Bering Sea (EBS), Greenland halibut ( Reinhardtius hippoglossoides ) and Pacific halibut ( Hippoglossus stenolepis ), which may be especially sensitive to climate-induced shifts in habitat due to strong seasonally and ontogenetically variable distributions. We analysed data from fishery-dependent and fishery-independent sources to determine how environmental variability influenced habitat use, thus gaining a uniquely comprehensive range of seasonal and geographic coverage of each species’ distribution. Greenland and Pacific halibut exhibited strong and contrasting responses to changes in temperature on the shelf, with catches decreasing and increasing, respectively, beyond 1 °C. The effect of temperature was not as prominent along the slope, suggesting that slope habitats may provide some insulation from shelf-associated environmental variability, particularly for Greenland halibut. With warming, Greenland halibut exhibited more of a bathymetric shift in distribution, while the shift was more latitudinal for Pacific halibut. Our results suggest that habitat partitioning may, in part, explain differences in Greenland and Pacific halibut distributions. This research adds to our understanding of how the distributions of two fish species at opposite extremes of their ranges in the EBS – Greenland halibut at the southernmost edge and Pacific halibut at the northernmost edge – may shift in relation to a changing ocean environment.

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

Pacific halibut on the move: a renewed understanding of adult migration from a coastwide tagging study

2013 ◽  
Vol 70 (4) ◽  
pp. 642-653 ◽  
Author(s):  
Raymond A. Webster ◽  
William G. Clark ◽  
Bruce M. Leaman ◽  
Joan E. Forsberg
Keyword(s):  
Bering Sea ◽  
Stock Assessment ◽  
Fish Length ◽  
Commercial Fishing ◽  
Ontogenetic Migration ◽  
Pacific Halibut ◽  
Hippoglossus Stenolepis ◽  
Migration Probability ◽  
The Bering Sea ◽  
Passive Integrated Transponder Tags

Results of a coastwide tagging study show that ontogenetic migration of Pacific halibut (Hippoglossus stenolepis) continues for larger fish, whereas in recent years the assumption had been that only smaller, younger fish migrated. In 2003–2004, a total of 67 000 Pacific halibut tagged with passive integrated transponder tags were released by the International Pacific Halibut Commission (IPHC) from Oregon to the Bering Sea. Portside scanning recovered over 3000 of these tags. Models were fitted that allowed commercial fishing mortality to be a function of fish length, year, and IPHC regulatory area, while migration probability was a function of area and length. Estimates from the models support the view that exploitation rates were much higher in eastern than western areas prior to the reduction of quotas following new results from a coastwide stock assessment in 2007. We explore possible explanations for differences between tagging and IPHC stock assessment results and note that this research provides confirmation of historical inferences regarding patterns of halibut migration based on conventional tagging.

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