A Cost-Benefit Method for Determining Optimum Closed Fishing Areas to Reduce the Trawl Catch of Prohibited Species

1984 ◽  
Vol 41 (1) ◽  
pp. 93-98 ◽  
Author(s):  
David A. Somerton ◽  
Jeffrey June
Keyword(s):  
Bering Sea ◽  
Cost Benefit ◽  
King Crab ◽  
Research Survey ◽  
Eastern Bering Sea ◽  
Yellowfin Sole ◽  
Survey Estimates ◽  
Paralithodes Camtschatica ◽  
Limanda Aspera ◽  
Trawl Fisheries

Red king crab (Paralithodes camtschatica), a prohibited species, are incidentally caught by United States trawl fisheries for yellowfin sole (Limanda aspera) and other groundfish in the eastern Bering Sea. To reduce this incidental catch, we propose a method for determining a king crab conservation zone where trawling would be prohibited. This method considers the gross revenue potentially gained by the yellowfin sole fishery and lost by the king crab fishery by allowing trawling in each of a number of equal-size areas. Utilizing exvessel prices and research survey estimates of species densities, areas are assigned relative values equal to the value of groundfish minus the value of king crab. By including all areas with negative relative values in the conservation zone, the potential gross revenue that could be obtained from the groundfish and king crab resource is maximized.

Availability of yellowfin sole Limanda aspera to the eastern Bering Sea trawl survey and its effect on estimates of survey biomass

2019 ◽  
Vol 211 ◽  
pp. 319-330 ◽  
Author(s):  
Daniel G. Nichol ◽  
Stan Kotwicki ◽  
Thomas K. Wilderbuer ◽  
Robert R. Lauth ◽  
James N. Ianelli
Keyword(s):  
Bering Sea ◽  
Trawl Survey ◽  
Eastern Bering Sea ◽  
Yellowfin Sole ◽  
Limanda Aspera

Contrasting the variability in spatial distribution of two juvenile flatfishes in relation to thermal stanzas in the eastern Bering Sea

2019 ◽  
Vol 77 (3) ◽  
pp. 953-963
Author(s):  
Cynthia Yeung ◽  
Daniel W Cooper
Keyword(s):  
Spatial Distribution ◽  
Bering Sea ◽  
Thermal Environment ◽  
Bottom Temperature ◽  
Eastern Bering Sea ◽  
Northward Expansion ◽  
Yellowfin Sole ◽  
Temperature Indices ◽  
Limanda Aspera ◽  
The Bering Sea

Abstract Groundfish species in the Bering Sea are undergoing pronounced changes in spatial distribution and abundance due to warming ocean temperatures. The main drivers of interannual variability in this ecosystem are the alternating warm and cold thermal stanzas. Yellowfin sole (Limanda aspera; YFS) and northern rock sole (Lepidopsetta polyxystra; NRS) are commercially-valuable flatfishes in the Bering Sea and are among the most dominant groundfish species there in numbers and biomass. We examined the variability in the spatial distribution and abundance of juvenile NRS and YFS in relation to the ice and temperature conditions associated with warm-cold thermal shifts from 1982 to 2017. The goal was to assess the implications of the fluctuating thermal environment for Bering Sea flatfish production. We found ice cover and bottom temperature indices in the preceding 1 to 3 years to be the best predictors of NRS juvenile distribution. In contrast, these indices were not significantly correlated with YFS juvenile distribution, which could be an artifact of their relatively low availability to sampling. A warm stanza, as the Bering Sea is currently in, is expected to favor high numbers of NRS juveniles and the northward expansion of their distribution.

Temperature-Dependent Growth of Juvenile Red King Crab (Paralithodes camtschatica) and its Effects on Size-at-Age and Subsequent Recruitment in the Eastern Bering Sea

1990 ◽  
Vol 47 (7) ◽  
pp. 1307-1317 ◽  
Author(s):  
Bradley G. Stevens
Keyword(s):  
Bering Sea ◽  
Published Data ◽  
Red King Crab ◽  
Sea Temperature ◽  
King Crab ◽  
Recruitment Failure ◽  
Eastern Bering Sea ◽  
Paralithodes Camtschatica ◽  
Size Interval ◽  
Size At Age

A temperature-based growth relationship was derived for juvenile red king crab (Paralithodes camtschatica) from published data. Growth of annual cohorts of crab was simulated at various locations in Bristol Bay, AK, using long-term water temperature observations, and the resulting mean sizes were compared with those observed by the annual National Marine Fisheries Service eastern Bering Sea crab survey. Results indicate that mean age-at-recruitment is 3–5 yr greater than previously estimated, and has decreased from 9.5 to 7.5 yr over the past decade as a result of increasing sea temperature. Single year-classes require 3–5 yr for complete recruitment to the 'mature' size interval, and recruitment in any year may consist of crabs from four to five year-classes. The high landings and subsequent crash of the Bering Sea red king crab population during the late 1970's probably originated from one or more adjacent strong year-classes in the late 1960's which recruited over a period of several years, followed by a period of recruitment failure and high mortality. Future stock–recruitment studies should account for the effects of multi-year recruitment and year-class overlap.

Taking Refuge from Bycatch Issues: Red King Crab (Paralithodes camtschaticus) and Trawl Fisheries in the Eastern Bering Sea

1993 ◽  
Vol 50 (9) ◽  
pp. 1993-2000 ◽  
Author(s):  
David A. Armstrong ◽  
Thomas C. Wainwright ◽  
Gregory C. Jensen ◽  
Paul A. Dinnel ◽  
Helle B. Andersen
Keyword(s):  
Bering Sea ◽  
Red King Crab ◽  
Paralithodes Camtschaticus ◽  
King Crab ◽  
Closed Area ◽  
Eastern Bering Sea ◽  
Male Crab ◽  
Before And After ◽  
Juvenile Habitat ◽  
Trawl Fisheries

Concerns about possibly heavy impacts of bottom trawl fisheries on red king crab (Paralithodes camtschaticus) pot fisheries in the eastern Bering Sea led in 1987 to an emergency closure of trawling in an area of adult and juvenile crab habitat. We examine the effectiveness of this bycatch refuge in protecting and possibly enhancing the crab resource using three approaches. First, bycatch of crab in trawl fisheries is a small proportion of total estimated abundance throughout the southeastern Bering Sea but may be high relative to stock abundance within the closed area and relative to annual crab landings; recent regulations have diminished this apparent effect. Effects of direct bycatch on the stock are obscured by lack of evidence on indirect effects of trawling, including crushing of crab and degredation of juvenile habitat. Second, surveys inside and outside the refuge before and after closure show no significant changes in abundance of female and prerecruit male crab. Third, important breeding and hatching grounds and juvenile habitat are not protected by the refuge, leaving long-term stock renewal subject to trawl impacts. We suggest that full consideration of the needs of all life history stages could lead to a more effective refuge design.

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.

A Computer Technique for Estimating the Size of Sexual Maturity in Crabs

1980 ◽  
Vol 37 (10) ◽  
pp. 1488-1494 ◽  
Author(s):  
D. A. Somerton
Keyword(s):  
Bering Sea ◽  
Sexual Maturity ◽  
Carapace Width ◽  
Logistic Function ◽  
Body Dimension ◽  
Computer Technique ◽  
Eastern Bering Sea ◽  
Paralithodes Camtschatica ◽  
Chionoecetes Bairdi ◽  
Size Estimates

A new computer technique for estimating the size of 50% sexual maturity from crab morphometric data is described. Using nonhierarchical cluster analysis, crabs are assigned to either of two maturity groups based on the size of one body dimension relative to another. The size of 50% maturity is then estimated by using nonlinear regression to fit a logistic function to percent maturity and size estimates. The size of 50% maturity in the eastern Bering Sea was estimated to be 102.8 and 101.9 mm (carapace length) for male and female Paralithodes camtschatica and 114.7 mm (carapace width) for male Chionoecetes bairdi. These estimates are similar to estimates for these species obtained previously by other techniques.Key words: crabs, growth, sexual maturity, Paralithodes, Chionoecetes

Sign in / Sign up

Export Citation Format

Share Document