Growth, spatial distribution, and abundance of benthic stages of the snow crab (Chionoecetes opilio) in Bonne Bay, Newfoundland, Canada

The growth and spatial distribution of postlarval snow crab (Chionoecetes opilio) from a relatively unexploitated stock in Bonne Bay, Newfoundland (Gulf of St. Lawrence), were described from the analysis of size distributions from trawls and a dredge sampled between 1988 and 1993. Immature crabs molted twice a year for instars I-V and then molted annually until females reached a terminal molt at maturity (instar X or XI) and males a juvenile stage (instar VIII). Thereafter, juvenile males could molt to another juvenile size, skip a molt, or achieve a terminal molt at the onset of the morphometric differentiation of their claws depending on the relative abundance of mature males. The life expectancy of females and males was 13 and 19 years, respectively. Males should recruit to the commercial size of 95 mm carapace width at instar XII, 9 years or more after settlement. Relative abundance of early benthic to commercial-size individuals suggests that small immature crabs (instar V) migrate from shallow rocky to deep muddy bottoms. The patchy spatial distribution observed for the snow crab appeared to be determined more by substrate and intraspecific factors than by depth. Seasonal movements to shallow waters by larger animals was related to density- and temperature-dependent factors associated with the reproductive and growth cycle.

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Morphometry and Gonad Maturity of Male Snow Crab, Chionoecetes opilio

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f92-271 ◽

1992 ◽

Vol 49 (12) ◽

pp. 2460-2468 ◽

Cited By ~ 49

Author(s):

Michel Comeau ◽

Gérard Y. Conan

Keyword(s):

Carapace Width ◽

Immature Stage ◽

Juvenile Stage ◽

Snow Crab ◽

Sexual Character ◽

Gonad Maturity ◽

Chionoecetes Opilio ◽

Juvenile Males ◽

The Relationship ◽

Determinant Factor

The relationship between chela height (CH) and carapace width (CW) of male snow crab, Chionoecetes opilio, goes through three allometric stages. The "immature stage" (mostly < 34 mm CW) evolves into a "juvenile stage" (34–120 mm CW) through a "juvenile molt" defining a change in allometry marked by an angular point around 34 mm CW. Fifty percent of males reach gonad maturity, defined by the presence of spermatophores inside the vasa deferentia, at an estimated size of 34 mm CW) The third allometric stage, "morphometrically mature," is separated from the juvenile stage by a "molt to morphometric maturity" at sizes ranging from 50 to 120 mm CW. Juvenile males have smaller claws than morphometrically mature males of the same size. This secondary sexual character is justified by a specific behavior of the males holding the pereipods of the female in one chela during precopulatory embrace. Male snow crab efficiently mate in nature with intermolt multiparous females only after reaching morphometric maturity. Therefore, the presence of spermatophores is not the sole determinant factor necessary for male copulation. Juvenile males larger than the minimum legal size of 95 mm CW are harvestable before, they may efficiently mate.

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Functional Maturity in Small Male Snow Crabs (Chionoecetes opilio)

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f88-244 ◽

1988 ◽

Vol 45 (12) ◽

pp. 2106-2109 ◽

Cited By ~ 22

Author(s):

G. P. Ennis ◽

R. G. Hooper ◽

D. M. Taylor

Keyword(s):

Rapid Development ◽

Carapace Width ◽

Reproductive Potential ◽

Snow Crab ◽

Small Male ◽

Chionoecetes Opilio ◽

In Captivity ◽

Breeding Migration ◽

High Level ◽

Snow Crabs

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].

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Hemolymph Ecdysone Concentration as a Function of Sexual Maturity in the Male Snow Crab (Chionoecetes opilio)

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f92-180 ◽

1992 ◽

Vol 49 (8) ◽

pp. 1619-1623 ◽

Cited By ~ 13

Author(s):

Roland J. Cormier ◽

Alan R. Fraser ◽

Richard F. J. Bailey ◽

Nicole Raymond

Keyword(s):

Sexual Maturity ◽

Carapace Width ◽

Dry Weight ◽

Mature Male ◽

Snow Crab ◽

Allometric Relationship ◽

Biochemical Basis ◽

Chionoecetes Opilio ◽

Relationship Of ◽

Juvenile Crab

Ecdysone concentrations in the hemolymph of juvenile and morphometrically mature male snow crab (Chionoecetes opilio) were determined by radioimmunoassay. A logarithmic transformation of the allometric relationship of the dry weight of the chelae versus the carapace width was used to identify morphometric maturity. Results indicate that concentrations of ecdysone found in the hemolymph of juvenile crab are higher than those found in morphometrically mature crab, thus providing a biochemical basis for the observation that the onset of sexual maturity seems to coincide with a terminal molt.

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Morphometric criterion of sexual and functional maturity; forecasting of stocks and recruitment for snow crab Chionoecetes opilio in the southern part of the Primorye subarea

Izvestiya TINRO ◽

10.26428/1606-9919-2014-178-124-134 ◽

2014 ◽

Vol 178 (3) ◽

pp. 124-134

Author(s):

Alexey G. Slizkin ◽

Valery N. Koblikov

Keyword(s):

Size Composition ◽

Snow Crab ◽

Chionoecetes Opilio ◽

Large Size ◽

Size Groups ◽

Stock Recruitment ◽

Population Recruitment ◽

First Time ◽

Commercial Size ◽

Commercial Stock

Stocks of large-hand and narrow-hand males of snow crab opilio are assessed separately for the first time on the data collected in the Primorye subarea southward from Cape Zolotoy (47°20’ N) in 2010-2013. Results of the separate assessment change fundamentally the conception of this exploited population recruitment. There is proposed to calculate the recruitment of its commercial stock from the number of narrow-hand males with commercial size instead of former method based on the number of pre-recruits size groups, that means that the large-hand males only are considered as commercial ones but the large-size narrow-hand males are their reserve. Dynamics of the size composition is analyzed and several options for calculation of the commercial stock recruitment after the final moult are proposed.

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Moulting and Mating of Snow Crabs, Chionoecetes opilio (O. Fabricius), in Shallow Waters of the Northwestern Gulf of Saint Lawrence

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f92-144 ◽

1992 ◽

Vol 49 (7) ◽

pp. 1282-1293 ◽

Cited By ~ 64

Author(s):

Bernard Sainte-Marie ◽

François Hazel

Keyword(s):

Carapace Width ◽

Male Competition ◽

Shallow Waters ◽

Beam Trawl ◽

Chionoecetes Opilio ◽

Data Support ◽

Mean Size ◽

Males And Females ◽

Gulf Of Saint Lawrence ◽

Snow Crabs

Chionoecetes opilio in baie Sainte-Marguerite, Gulf of Saint Lawrence, were sampled by beam trawl in spring from 1988 to 1991 and by divers in March 1991 to document an hypothesized annual moult in shallow waters. Each spring, C. opilio occurred at 4–20 m of depth where 29.3–97.3% of males and 20.3–81.4% of females were moulting or recently moulted. Males and females [Formula: see text] carapace width (CW) moulted only on bottoms < 60 m. Females were mature at [Formula: see text] CW and males were morphometrically mature at [Formula: see text] CW. Overall, 0.3% of morphometrically mature (N = 575) and 23% of morphometrically immature (N = 826) males [Formula: see text] CW, exclusive of soft-shelled, had a visible second carapace. These and other data support the hypothesis of a terminal moult coincident with morphometric maturity. Pubescent females mated with males 59.9–109.3 mm CW (88% were < 95 mm CW), 97% of which were morphometrically mature (N = 120). Mean size of these males was greater than that of males grasping immature females or other males, indicating male competition for pubescent females. Morphometrically mature males were larger on bottoms > 80 m deep, where multiparous females concentrated, than on shallower bottoms.

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Interannual variability of sperm reserves and fecundity of primiparous females of the snow crab (Chionoecetes opilio) in relation to sex ratio

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f02-162 ◽

2002 ◽

Vol 59 (12) ◽

pp. 1932-1940 ◽

Cited By ~ 27

Author(s):

Bernard Sainte-Marie ◽

Jean-Marie Sévigny ◽

Mireille Carpentier

Keyword(s):

Sex Ratio ◽

Carapace Width ◽

Weight Percent ◽

Snow Crab ◽

Adult Males ◽

Reproductive Condition ◽

Embryo Production ◽

Potential Fecundity ◽

Chionoecetes Opilio ◽

Female Promiscuity

Demographics of adults and reproductive condition of primiparous (first brood) females of the snow crab (Chionoecetes opilio) were monitored annually from 1994 to 2002 at a fished site to investigate the possibility that sperm supply limits embryo production. Abundance of primipara fluctuated 533-fold because of a recruitment pulse, and this caused a large oscillation in the sex ratio of adult males to primipara. Annual mean of stored ejaculate weight (SL) and potential fecundity index (PF, clutch weight × percent fertilized eggs) adjusted to constant primipara carapace width ranged from 31 to 130 mg by spermatheca and from 1.97 to 3.43 g by clutch, respectively. Annual mean of SL and number of stored sperm (range 3.81 × 106 to 35.00 × 106 sperm by spermatheca) decreased when sex ratio decreased, probably because of a combined reduction of sperm allocation and female promiscuity. Annual mean PF was negatively correlated with abundance of small males, which may reflect egg losses during postoviposition matings. Although sociosexual context has a large impact on reproductive condition of primipara, the possibility that sperm supply limits embryo production could not be confirmed or excluded because of the complexity of snow crab mating behavior.

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Geographic variation in the size-related terminal-molt proportion and carapace width of the male snow crab Chionoecetes opilio off the Pacific coast of southern Tohoku, Japan

NIPPON SUISAN GAKKAISHI ◽

10.2331/suisan.16-00059 ◽

2017 ◽

Vol 83 (2) ◽

pp. 156-162 ◽

Cited By ~ 1

Author(s):

KAZUYOSHI TAKASAKI ◽

TAKESHI TOMIYAMA

Keyword(s):

Geographic Variation ◽

Pacific Coast ◽

Carapace Width ◽

Snow Crab ◽

Chionoecetes Opilio ◽

The Pacific

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The effect of white and green LED-lights on the catch efficiency of the Barents Sea snow crab (Chionoecetes opilio) pot fishery

PLoS ONE ◽

10.1371/journal.pone.0258272 ◽

2021 ◽

Vol 16 (10) ◽

pp. e0258272

Author(s):

Kristine Cerbule ◽

Bent Herrmann ◽

Eduardo Grimaldo ◽

Leif Grimsmo ◽

Jørgen Vollstad

Keyword(s):

Field Experiments ◽

Barents Sea ◽

Carapace Width ◽

Snow Crab ◽

Chionoecetes Opilio ◽

Light Emitting ◽

Green Led ◽

Minimum Landing Size ◽

White Light Emitting Diodes ◽

Led Lights

In commercial snow crab (Chionoecetes opilio) fishery, the catch efficiency of the conical pots is important for increasing the profitability of the industry. This study evaluated the effect of adding green and white light emitting diodes (LED) on the catch efficiency of commercially used conical pots. The results from the field experiments showed that inserting artificial lights significantly increases the catch efficiency for snow crab over the minimum landing size of 95 mm carapace width of up to 76% when using green LED, and by 52–53% on average when using white LED. This study shows that it is possible to improve the catch efficiency of the snow crab fishery by applying artificial LED lights to the conical snow crab pots, potentially resulting in an important economic benefit to the snow crab fishery.

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Spatial distribution of catch and effort in a fishery for snow crab (Chionoecetes opilio): tests of predictions of the ideal free distribution

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f03-076 ◽

2003 ◽

Vol 60 (8) ◽

pp. 897-909 ◽

Cited By ~ 57

Author(s):

Douglas P Swain ◽

Elmer J Wade

Keyword(s):

Spatial Distribution ◽

Resource Distribution ◽

Ideal Free Distribution ◽

Snow Crab ◽

Catch Per Unit Effort ◽

Chionoecetes Opilio ◽

Free Distribution ◽

Crab Abundance ◽

Ideal Free ◽

The Ideal

The ideal free distribution (IFD), a hypothesis from behavioural ecology, predicts that fishery effort should map resource distribution better than catch-per-unit-effort (CPUE) when interference competition occurs in the fishery. We tested this prediction using data from the fishery and annual research survey for snow crab (Chionoecetes opilio) in the southern Gulf of St. Lawrence. Effort was positively correlated with the local abundance of crabs in all years. Correlations between CPUE and local crab abundance were also positive in some years, but negative in others. In the latter cases, CPUE and effort were also negatively correlated, suggesting intense competition in the fishery. In most years, CPUE tended to be equalized among areas compared with the distributions of effort and local crab abundance, as predicted by the IFD. In most years, differences in spatial distribution were more significant between CPUE and crab abundance than between effort and crab abundance. Although effort was the more reliable indicator of resource distribution, even it provided a distorted view of this distribution, as predicted given expected violations of IFD assumptions. For example, effort tended to be higher than expected on fishing grounds near home ports and lower than expected on distant grounds.

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