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

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.

1988 ◽  
Vol 45 (12) ◽  
pp. 2106-2109 ◽  
Author(s):  
G. P. Ennis ◽  
R. G. Hooper ◽  
D. M. Taylor

The mean size of male snow crabs (Chionoecetes opilio) in sexual pairs during the annual spring breeding migration to shallow water in Bonne Bay, Newfoundland, decreased from 118.6 mm carapace width (CW) in 1983 to 100.3 mm in 1987. This decrease is due to an increase in males <95 mm CW participating from 1.5% in 1983 to 32.3% in 1987. This change appears to have resulted from a reduced abundance of commercial size [Formula: see text] males due to a rapid development of an illegal fishery on this previously unfished population and, as a consequence, less competition between males for possession of females. The percentages of spermathecae containing new spermatophores for females paired with males <95 mm CW (67%) and those with males [Formula: see text] (79%) were not significantly different. We assumed that each female with new spermatophores had recently mated with the male with which it was paired. Observations on selected pairs in captivity showed that males <95 mm CW are capable of mating with both primiparous and muitiparous females. Our results indicate that small mature males can replace large males in breeding activity in a snow crab population. We conclude that in the male-only snow crab fishery in Atlantic Canada with a minimum legal size of 95 mm CW, population reproductive potential is maintained at a high level despite high exploitation rates on males [Formula: see text].


1981 ◽  
Vol 38 (2) ◽  
pp. 163-174 ◽  
Author(s):  
David A. Somerton

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


2015 ◽  
Vol 72 (5) ◽  
pp. 1525-1529 ◽  
Author(s):  
J. Daniel Urban

Abstract Fish and invertebrates that are unintentionally captured during commercial fishing operations and then released back into the ocean suffer mortality at unknown rates, introducing uncertainty into the fishery management process. Attempts have been made to quantify discard mortality rates using reflex action mortality predictors or RAMP which use the presence or absence of a suite of reflexes to predict discard mortality. This method was applied to snow crab, Chionoecetes opilio, during the 2010–2012 fisheries in the Bering Sea. Discard mortality in the fishery is currently assumed to be 50% in stock assessment models, but that rate is not based on empirical data and is widely recognized to be in need of refinement. Over 19 000 crab were evaluated using the RAMP method. The estimated discard mortality rate was 4.5% (s.d. = 0.812), significantly below the rate used in stock assessment models. Predicted discard mortality rates from the 2010 to 2012 study were strongly correlated with the air temperature at the St Paul Island airport in the Pribilof Islands. Using this relationship, the discard mortality rate from 1991 to 2011 was estimated at 4.8% (s.d. = 1.08).


1980 ◽  
Vol 37 (10) ◽  
pp. 1488-1494 ◽  
Author(s):  
D. A. Somerton

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


2016 ◽  
Vol 73 (12) ◽  
pp. 1800-1814 ◽  
Author(s):  
Joel B. Webb ◽  
Laura M. Slater ◽  
Ginny L. Eckert ◽  
Gordon H. Kruse

Development of refined indices of female reproductive potential is needed for estimation of alternative biological reference points for the eastern Bering Sea (EBS) snow crab (Chionoecetes opilio) fishery, which is managed with large male-only harvest regulations. Females were collected from 2007 to 2009 to investigate seasonal and interannual variation in fecundity with maternal size, shell condition (a proxy for age after maturity), and recent mating and again in 2010 to examine biochemical measures (carbon, hydrogen, and nitrogen) of embryo quality. Mean model-adjusted fecundity was highest for primiparous and young multiparous females and declined with advancing shell condition, presumably from senescence. This pattern was also found for clutch fullness indices evaluated from 20 years of stock assessment survey data. Indicators of low female sperm reserves were associated with decreased (∼10%) fecundity for multiparous females. Seasonal comparison of size–fecundity relationships suggested that embryo loss during brooding was minimal, and embryo quality analyses suggested that strong variation with maternal characteristics was unlikely. Finally, fecundity-at-size of EBS females may be lower than that of conspecifics in Japan and eastern Canada.


2015 ◽  
Vol 8 ◽  
Author(s):  
Michel E. Hendrickx

The deep-water mysidCeratomysis spinosaFaxon, 1893, previously known from Panama, Japan, the Sea of Okhotsk, the Bering Sea and Alaska, USA is reported for the first time off the western coast of Mexico, in the eastern Pacific. The specimens, a male of 27.5 mm in total length (TL) and five females of 28.5–34.5 mm TL, were collected between depths of 1296 and 1580 m. The telson is illustrated, showing numerous setae on the lateral margins, and longer, robust setae in the distal third and on the posterior margin.


1987 ◽  
Vol 44 (6) ◽  
pp. 1143-1156 ◽  
Author(s):  
Lewis S. Incze ◽  
David A. Armstrong ◽  
Sharon L. Smith

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.


1996 ◽  
Vol 26 ◽  
pp. 221-227 ◽  
Author(s):  
TR Meyers ◽  
JF Morado ◽  
AK Sparks ◽  
GH Bishop ◽  
T Pearson ◽  
...  

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