Abundance of Larval Tanner Crabs (Chionoecetes spp.) in Relation to Adult Females and Regional Oceanography of the Southeastern Bering Sea

1987 ◽  
Vol 44 (6) ◽  
pp. 1143-1156 ◽  
Author(s):  
Lewis S. Incze ◽  
David A. Armstrong ◽  
Sharon L. Smith
Keyword(s):  
Bering Sea ◽  
Reproductive Output ◽  
Larval Abundance ◽  
Sampling Effort ◽  
Sharp Decline ◽  
Adult Females ◽  
Hydrographic Conditions ◽  
Analysis Of Results ◽  
Circulation Distribution ◽  
Chionoecetes Bairdi

Abundances of larval Chionoecetes bairdi and C. opilio in the southeastern Bering Sea are compared for springs of 1978 through 1981. Geographical subareas of the shelf were designated for statistical analysis of results to accommodate variations in hydrographic conditions and circulation, distribution of benthic populations, and distribution of planktonic sampling effort. Maximum observed abundances of first-stage zoeae were 1230 and 12 697∙m−2 for C. bairdi (during May) and C. opilio (during April), respectively. Numbers exceeding 10% of these values were common over some portions of the shelf during all years of study. Significant (P < 0.001) interannual differences in larval abundance were detected: in three subareas for C. opilio and in one for C. bairdi. The sharp decline in abundance of larval C. opilio after 1979 in two of the subareas could be accounted for by regional declines in numbers of adult female crabs. This was not true of the remaining subarea where two weak larval year-classes of C. opilio (1980 and 1981) and one of C. bairdi (1980) occurred despite an abundance of adult females. Vertical distribution of larval crabs is shown and the potential roles of advection, planktonic conditions, and reproductive output are evaluated with respect to observed patterns of larval abundance.

Relation of Number of Eggs and Egg Length to Carapace Width in the Brachyuran Crabs Chionoecetes bairdi and C. opilio from the Southeastern Bering Sea and C. opilio from the Gulf of St. Lawrence

1976 ◽  
Vol 33 (11) ◽  
pp. 2592-2595 ◽  
Author(s):  
Evan Haynes ◽  
John F. Karinen ◽  
Jeffrey Watson ◽  
Daniel J. Hopson
Keyword(s):  
Bering Sea ◽  
Carapace Width ◽  
Reproductive Potential ◽  
Relative Number ◽  
Chionoecetes Opilio ◽  
Adult Females ◽  
Brachyuran Crabs ◽  
Chionoecetes Bairdi ◽  
First Time ◽  
The Bering Sea

The number of eggs attached to pleopods of Chionoecetes bairdi and C. opilio from the southeastern Bering Sea increased at a rate proportional to about the 3.4 and 2.7 power of carapace width, respectively, but for C. opilio from the Gulf of St. Lawrence it increased to the 4.2 power. The range in carapace width and number of eggs for crabs from the Bering Sea of a given carapace width were considerably greater for C. bairdi than for C. opilio. In the southeastern Bering Sea, the reproductive potential for adult females of C. bairdi with mixed spawning history is approximately 4 times greater than that of C. opilio spawning for the first time. Chionoecetes opilio females with mixed spawning history in the Gulf of St. Lawrence carry more eggs for a given carapace width than first-time spawners from the southeastern Bering Sea. Our data were not sufficient to resolve the question of relative number of eggs for crabs of various ages.

scholarly journals Epilithic community development on artificial reefs deployed along a cross-shelf environmental gradient off Paraná state, southern Brazil

2011 ◽  
Vol 59 (spe1) ◽  
pp. 43-53 ◽  
Author(s):  
Frederico Brandini ◽  
Ariel Scheffer da Silva
Keyword(s):  
Large Scale ◽  
Diversity Index ◽  
Artificial Reef ◽  
Larval Abundance ◽  
Percent Cover ◽  
Southern Brazil ◽  
Factors Affecting ◽  
Hydrographic Conditions ◽  
One Year ◽  
General Community

Concrete modules were deployed on the bottom of the 11, 18 and 30 meters isobaths along a cross-shelf hydrographic gradient off Paraná State, Southern Brazil, with the purpose of studying the colonization of sessile epilithic macroinvertebrates on artificial surfaces. After one year of submersion a total of 63 species of epilithic organisms were identified, dominated by Ostrea puelchana, Chthamalus bisinuatus, Balanus cf spongicola, Astrangia cf rathbuni, Didemnum spp, poryphers and bryozoans. Diversity index and percent cover at reef stations placed at 11, 18 and 30 meters isobaths were respectively 2.28 and 66.7%, 2.79 and 96.6% and 1.66 and 77.4%. Differences of general community structure among the three assemblages were not clearly related to the general environmental conditions at the bottom layers near the reef stations. Turbidity and larval abundance are discussed as important factors affecting colonization processes. Results indicate that depths between 15-20 meters are more suitable for the implementation of large scale artificial reef systems in the inner shelf off Paraná and, possibly, throughout the inner shelves off southern Brazil with similar hydrographic conditions.

Patterns in connectivity and retention of simulated Tanner crab (Chionoecetes bairdi) larvae in the eastern Bering Sea

2015 ◽  
Vol 138 ◽  
pp. 475-485 ◽  
Author(s):  
Jonathan I. Richar ◽  
Gordon H. Kruse ◽  
Enrique Curchitser ◽  
Albert J. Hermann
Keyword(s):  
Bering Sea ◽  
Eastern Bering Sea ◽  
Tanner Crab ◽  
Chionoecetes Bairdi

Regional Variation in the Size of Maturity of Two Species of Tanner Crab (Chionoecetes bairdi and C. opilio) in the Eastern Bering Sea, and Its Use in Defining Management Subareas

1981 ◽  
Vol 38 (2) ◽  
pp. 163-174 ◽  
Author(s):  
David A. Somerton
Keyword(s):  
Bering Sea ◽  
Regional Variation ◽  
Carapace Width ◽  
Minimum Size ◽  
Computer Technique ◽  
Eastern Bering Sea ◽  
Commercial Harvest ◽  
Tanner Crab ◽  
Size Limits ◽  
Chionoecetes Bairdi

Minimum size limits for the commercial harvest of tanner crab (Chionoecetes bairdi and C. opilio) are based on the sizes of sexual maturity. Establishing such size limits in the eastern Bering Sea is complicated by a large regional variation in the size of maturity. A computer technique was developed which partitioned the eastern Bering Sea into subareas that were relatively homogeneous with respect to the size of maturity. The best partitioning for C. bairdi was a separation of the eastern Bering Sea into two subareas along 167°15′N longitude. No acceptable partitioning could be found for C. opilio. The size of 50% maturity for male C. bairdi was estimated to be 108.9 mm carapace width in the western subarea and 117.0 mm in the eastern subarea. The size of maturity upon which the current minimum size for C. bairdi is based is nearly the same as the size estimated for the western subarea but significantly less than the size estimated for the eastern subarea.Key words: crabs, size of maturity, Chionoecetes bairdi, Chionoecetes opilio, tanner crab, eastern Bering Sea

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

scholarly journals Effect of bitter crab disease on rebuilding in Alaska Tanner crab stocks

2010 ◽  
Vol 67 (9) ◽  
pp. 2027-2032 ◽  
Author(s):  
M. Shareef M. Siddeek ◽  
Jie Zheng ◽  
Joseph F. Morado ◽  
Gordon H. Kruse ◽  
William R. Bechtol
Keyword(s):  
Bering Sea ◽  
Potential Effect ◽  
Management Plan ◽  
Reference Points ◽  
Commercial Fishing ◽  
Southeast Alaska ◽  
Control Rules ◽  
Eastern Bering Sea ◽  
Tanner Crab ◽  
Chionoecetes Bairdi

Abstract Siddeek, M. S. M., Zheng, J., Morado, J. F., Kruse, G. H., and Bechtol, W. R. 2010. Effect of bitter crab disease on rebuilding in Alaska Tanner crab stocks. – ICES Journal of Marine Science, 67: 2027–2032. Eastern Bering Sea (EBS) Tanner crab Chionoecetes bairdi stocks were declared overfished in 1996 and were closed to commercial fishing between 1997 and 2004. Subsequent management was based on a rebuilding plan using criteria from the previous US federal fisheries management plan (FMP). Under the revised 2008 FMP, reference points changed for mature biomass (male only vs. total), as well as catch levels (total vs. retained), resulting in different rebuilding criteria. We performed a rebuilding analysis using age-, sex-, and size-structured simulations incorporating recent changes in overfishing definitions. Specifically, we compared the potential effect of additional mortality that bitter crab disease could have on rebuilding performance of lightly infected EBS and heavily infected southeast Alaska Tanner crab stocks. The results suggest that under the assumed recruitment scenario, the new control rules are adequate to rebuild the depleted lightly infected EBS stock, but not the heavily infected southeast Alaska stock.

Should harvest control rules for male-only fisheries include reproductive buffers? A Bering Sea Tanner crab (Chionoecetes bairdi) case study

2021 ◽  
Vol 243 ◽  
pp. 106049
Author(s):  
Madison A. Heller-Shipley ◽  
William T. Stockhausen ◽  
Benjamin J. Daly ◽  
André E. Punt ◽  
Scott E. Goodman
Keyword(s):  
Bering Sea ◽  
Control Rules ◽  
Tanner Crab ◽  
Chionoecetes Bairdi ◽  
Harvest Control Rules

scholarly journals Assessing population structure and body condition to inform conservation strategies for a small isolated Asian elephant (Elephas maximus) population in southwest China

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0248210
Author(s):  
Yakuan Sun ◽  
Ying Chen ◽  
Juan José Díaz-Sacco ◽  
Kun Shi
Keyword(s):  
Population Structure ◽  
Body Condition ◽  
Asian Elephant ◽  
Elephas Maximus ◽  
Conservation Strategies ◽  
Limiting Factor ◽  
Sampling Effort ◽  
Adult Males ◽  
Adult Females ◽  
Elephant Population

The Asian elephant (Elephas maximus) population in Nangunhe National Nature Reserve in China represents a unique evolutionary branch that has been isolated for more than twenty years from neighboring populations in Myanmar. The scarcity of information on population structure, sex ratio, and body condition makes it difficult to develop effective conservation measures for this elephant population. Twelve individuals were identified from 3,860 valid elephant images obtained from February to June 2018 (5,942 sampling effort nights) at 52 camera sites. Three adult females, three adult males, one subadult male, two juvenile females, two juvenile males and one male calf were identified. The ratio of adult females to adult males was 1:1, and the ratio of reproductive ability was 1:0.67, indicating the scarcity of reproductive females as an important limiting factor to population growth. A population density of 5.32 ± 1.56 elephants/100 km2 was estimated using Spatially Explicit Capture Recapture (SECR) models. The health condition of this elephant population was assessed using an 11-point scale of Body Condition Scoring (BCS). The average BCS was 5.75 (n = 12, range 2–9), with adult females scoring lower than adult males. This isolated population is extremely small and has an inverted pyramid age structure and therefore is at a high risk of extinction. We propose three plans to improve the survival of this population: improving the quality and quantity of food resources, removing fencing and establishing corridors between the east and wet parts of Nangunhe reserve.

scholarly journals Distribution of Bitter Crab Syndrome in Tanner crabs (Chionoecetes bairdi, C. opilio) from the Gulf of Alaska and the Bering Sea

1996 ◽  
Vol 26 ◽  
pp. 221-227 ◽  
Author(s):  
TR Meyers ◽  
JF Morado ◽  
AK Sparks ◽  
GH Bishop ◽  
T Pearson ◽  
...  
Keyword(s):  
Bering Sea ◽  
Gulf Of Alaska ◽  
Chionoecetes Bairdi ◽  
The Bering Sea
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