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.

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].

SERUM PROTEIN CONCENTRATION AND SOMATIC INDEX IN RELATION TO MORPHOMETRIC MATURITY FOR MALE SNOW CRAB, CHIONOECETES OPILIO (O. FABRICIUS, 1788), IN THE BAIE DES CHALEURS, CANADA (DECAPODA, BRACHYURA)

Crustaceana ◽  
1999 ◽  
Vol 72 (5) ◽  
pp. 497-506 ◽  
Author(s):  
Michel Comeau ◽  
Marc Lanteigne ◽  
Roland Cormier
Keyword(s):  
Serum Protein ◽  
Protein Concentration ◽  
Mature Male ◽  
Snow Crab ◽  
Juvenile Male ◽  
Chionoecetes Opilio ◽  
Wet Weight ◽  
Snow Crabs ◽  
Somatic Index ◽  
Serum Protein Concentration

AbstractThe serum protein concentrations of juvenile and mature male snow crabs, Chionoecetes opilio, were measured using a refractometer. The somatic indices of juvenile and mature male snow crab were calculated using the weight of the dry flesh of the chelae versus its wet weight. Results indicate that juvenile male snow crab have significantly higher serum protein concentrations and significantly lower somatic indices than their mature counterparts. These observations are attributed to basic physiological differences that could be explained by a terminal moult. Les concentrations en proteines seriques de males juveniles et a maturite du crabe des neiges Chionoecetes opilio ont ete mesurees au moyen d'un refractometre. Les indices somatiques de ces individus ont ete calcules en utilisant le rapport entre le poids sec et le poids humide de la chair. Les resultats indiquent que les individus males juveniles ont des concentrations en proteines seriques significativement plus elevees et des indices somatiques significativement plus bas que les individus males matures. Ces observations sont attribuees a des differences physiologiques de base qui peuvent etre expliquees par une mue terminale.

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 Per Molt and Limb Regeneration in the Spider Crab, Chionoecetes opilio

1976 ◽  
Vol 33 (7) ◽  
pp. 1644-1649 ◽  
Author(s):  
R. J. Miller ◽  
J. Watson
Keyword(s):  
Least Squares ◽  
Sexual Maturity ◽  
Carapace Width ◽  
Limb Regeneration ◽  
Percentage Increase ◽  
Spider Crab ◽  
Chionoecetes Opilio ◽  
Size Growth ◽  
Zero Growth ◽  
The Difference

Spider crabs, Chionoecetes opilio, were held in the laboratory for observations on carapace width increments and limb regeneration per molt. The merus (the longest limb segment) of autotomized limbs regenerated to 48 and 73% of their full length, irrespective of crab size, on the first and second molt, respectively. Fitting least squares regressions to percentage increase of carapace width per molt (Y) vs. premolt carapace width (X [in millimeters]) gave the following equations: immature males Y = 40.7 − 0.363X; immature females Y = 45.3 − 0.444X; mature males Y = 14.2 + 0.051X; and females’ terminal molt to maturity Y = 14.0 − 0.014X. Only the slopes for the first two equations differed significantly from zero. Growth per molt decreased with sexual maturity for both sexes and was significantly less for females molting to maturity than for mature males of the same size. Growth per molt for immature females was significantly greater than for immature males, but the difference was slight.

Cuticular repair in the mature male snow crab, Chionoecetes opilio (Majidae; Crustacea): relation to ecdysteroids

1992 ◽  
Vol 70 (2) ◽  
pp. 314-319 ◽  
Author(s):  
K. Halcrow ◽  
C. G. H. Steel
Keyword(s):  
Light Microscopy ◽  
Dorsal Surface ◽  
Mature Male ◽  
Snow Crab ◽  
Chionoecetes Opilio ◽  
Snow Crabs

Morphometrically mature male snow crabs, Chionoecetes opilio, are not known to molt; they are believed to lack functional Y-organs and hence molting hormones. Small regions of the dorsal surface of crabs were damaged and the ensuing repair of the cuticle was followed by light microscopy at intervals of up to 60 days. Events within the limb base after forced autotomy of a single pereiopod were also investigated and compared with cuticle deposition in limb bases of pereiopods autotomized before the crabs' arrival in the laboratory. Circulating ecdysteroids were assayed by radioimmunoassay at intervals throughout the experiments. New cuticle was deposited in response to all types of injury and in a manner similar to that described previously. New cuticle was deposited across the breakage plane of autotomized limb bases; a complete and substantial layer was present in many of the bases of previously autotomized legs. Neither basal growth nor premolt growth was detected in the base of any autotomized limb. Ecdysteroids were detectable in the hemolymph of most crabs but at low titers, ranging from 6.0 to 11.6 ng/mL.

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.

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.

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