Morphometry and Gonad Maturity of Male Snow Crab, Chionoecetes opilio

1992 ◽  
Vol 49 (12) ◽  
pp. 2460-2468 ◽  
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.

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

1998 ◽  
Vol 55 (1) ◽  
pp. 262-279 ◽  
Author(s):  
Michel Comeau ◽  
Gérard Y Conan ◽  
Francesc Maynou ◽  
Guy Robichaud ◽  
Jean-Claude Therriault ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Relative Abundance ◽  
Carapace Width ◽  
Growth Cycle ◽  
Snow Crab ◽  
Shallow Waters ◽  
Temperature Dependent ◽  
Chionoecetes Opilio ◽  
Juvenile Males ◽  
Commercial Size

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.

Maturity and Molt Status of Crustacea: Determining Classification without Prior Criteria

1994 ◽  
Vol 51 (2) ◽  
pp. 408-416 ◽  
Author(s):  
William G. Warren
Keyword(s):  
Iterative Procedure ◽  
A Priori ◽  
Carapace Width ◽  
Snow Crab ◽  
Data Sets ◽  
Chionoecetes Opilio ◽  
Relationship Of ◽  
The Relationship

Existing methodology for estimation is reviewed for the situation where, a priori, the existence of two or more groups can be postulated but, in contrast with discriminant analysis, there is no sample in which the correct categories are known. Such mixture models are applied to two data sets related to the maturity and molt status of snow crab, Chionoecetes opilio, namely (1) the classification of crab as morphometrically mature or immature on the basis of the chela height – carapace width relationship and (2) the determination of the number of molts of crab, during a known period at liberty, from the relationship of size at release and size at recapture of tagged animals, in the latter example, a theoretical constraint is imposed that links the relationships at the different stages. The solution is obtained by "nesting" an iterative procedure within an EM algorithm. The method permits hypotheses concerning the number of groups to be tested, including the hypothesis that the data come from a single homogenous group, and each individual is assigned a probability of belonging to a group.

Functional Maturity in Small Male Snow Crabs (Chionoecetes opilio)

1988 ◽  
Vol 45 (12) ◽  
pp. 2106-2109 ◽  
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].

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

1992 ◽  
Vol 49 (8) ◽  
pp. 1619-1623 ◽  
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.

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

2002 ◽  
Vol 59 (12) ◽  
pp. 1932-1940 ◽  
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.

scholarly journals Biomorphometry of coconut crabs (Birgus latro) in Laigoma Island, North Maluku, Indonesia

2021 ◽  
Vol 890 (1) ◽  
pp. 012065
Author(s):  
Suryani ◽  
M S Widodo ◽  
U Yanuhar ◽  
A Suprijanto
Keyword(s):  
Sex Ratio ◽  
Carapace Width ◽  
Maturity Level ◽  
Ratio Distribution ◽  
Spawning Period ◽  
Male And Female ◽  
Gonad Maturity ◽  
Native Habitat ◽  
The Relationship ◽  
Land Clearance

Abstract Coconut crab is a coastal animal that lives in costal forest on islands of tropical Indo-Pacific. Crab populations are currently under threat of extinction. Several issues contribute to this, including high levels of exploitation, degradation of their native habitat, land clearance, and plantations development. This study aimed to examine the biomorphometric of coconut crabs, which includes the composition, sex ratio, distribution, widht and weight relation, condition factors and gonad maturity level. The descriptive explorative methods was used in this research. The results showed that the composition of 156 coconut crabs consisted of 82 females. The results obtained a balanced sex ratio. The size of the carapace width obtained ranged from 40.15 to 88.55 mm, with a weight of 150-565 grams. The relationship between width and capacity is allometric. The values obtained from these factors ranged from 1.01 to 1.03 for men and 1.01 to 1.012 for females. The gonad maturity level of male and female mud crabs was dominated by TKG III and IV. This indicated that the research time was in spawning period.

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

PLoS ONE ◽  
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.

scholarly journals Growth of the snow crab Chionoecetes opilio estimated by carapace width frequency analysis in the waters off the Pacific coast of northern Honshu, Japan

2007 ◽  
Vol 73 (3) ◽  
pp. 487-494 ◽  
Author(s):  
YUJI UEDA ◽  
MASAKI ITO ◽  
TSUTOMU HATTORI ◽  
YOJI NARIMATSU ◽  
KUNIHIRO FUJIWARA ◽  
...  
Keyword(s):  
Frequency Analysis ◽  
Pacific Coast ◽  
Carapace Width ◽  
Snow Crab ◽  
Chionoecetes Opilio ◽  
The Pacific

scholarly journals A spatiotemporal model for snow crab (Chionoecetes opilio) stock size in the southern Gulf of St. Lawrence

2017 ◽  
Vol 74 (11) ◽  
pp. 1808-1820 ◽  
Author(s):  
Noel G. Cadigan ◽  
Elmer Wade ◽  
Anders Nielsen
Keyword(s):  
East Coast ◽  
Snow Crab ◽  
Natural Mortality ◽  
General Increase ◽  
Chionoecetes Opilio ◽  
Spatiotemporal Model ◽  
Stock Size ◽  
Stock Biomass ◽  
Survey Results ◽  
The Relationship

We develop a high-resolution spatiotemporal model of stock size and harvest rates for snow crab (Chionoecetes opilio) in the southern Gulf of St. Lawrence, which supports an economically important fishery off the east coast of Canada. It is a spatial and weekly model during 1997–2014 that utilizes within-season depletion based on catch per unit of effort (CPUE; kg·pot–1) and also biomass values from a survey designed specifically for this stock. The model is formulated in a state-space framework. The main contribution of the model is to provide a better understanding of fishery-dependent factors that affect CPUE. There is strong evidence of density dependence in the relationship with CPUE and stock biomass, in addition to a general increase in CPUE catchability over time that may be related to changes in gear soak time and spatial variation in catchability. We also find that a natural mortality rate of 0.4 provides a better fit to survey results. Model results suggest that there is no evidence of effort saturation in the fishery.

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