Biology of Rock Crab (Cancer irroratus) in Northumberland Strait

1972 ◽  
Vol 29 (2) ◽  
pp. 161-166 ◽  
Author(s):  
D. J. Scarratt ◽  
Robert Lowe
Keyword(s):  
Sex Ratio ◽  
Surface Waters ◽  
Sea Urchins ◽  
Carapace Width ◽  
Late Summer ◽  
Fishing Gear ◽  
Size At Maturity ◽  
Cancer Irroratus ◽  
Rock Crab ◽  
Commercial Size

Divers hand-collected 342 rock crabs (Cancer irroratus) ranging from 4.2 mm carapace width to 97 mm (females) and 127 mm (males). The sex ratio (1.37:1) was biased in favour of males. Of 2929 crabs taken in commercial lobster fishing gear, 92% were above the minimum commercial size of 89 mm, and of these 99.1% were male. Smallest size at maturity was 60 mm for females and 69 mm for males. Breeding occurred in late summer and fall. Larvae were present in surface waters from June to September. Prey of crabs > 25 mm consisted principally of polychaetes, mussels, starfish, and sea urchins. Crabs less than about 65 mm inhabit rocky areas; larger crabs move out onto sand and mud. The fishable population is probably not in significant competition with lobsters for food or space.

Some Estimates of Population Density and Feeding Habits of the Rock Crab, Cancer irroratus, in a Kelp Bed in Nova Scotia

1982 ◽  
Vol 39 (4) ◽  
pp. 636-639 ◽  
Author(s):  
N. C. Drummond-Davis ◽  
K. H. Mann ◽  
R. A. Pottle
Keyword(s):  
Nova Scotia ◽  
Population Density ◽  
Sea Urchins ◽  
Feeding Habits ◽  
Atlantic Coast ◽  
Carapace Width ◽  
Hermit Crabs ◽  
Cancer Irroratus ◽  
Kelp Bed ◽  
Rock Crab

The population density of rock crabs (Cancer irroratus) in a kelp bed on the Atlantic coast of Nova Scotia was examined by mark–recapture techniques and found to be about one crab (> 45-mm carapace width) per 2 square metres. Prey taken by the crabs included hermit crabs (Pagurus), mussels (Mytilus), sea urchins (Strongylocentrotus), and various small crustaceans and polychaetes. It was concluded that the crab population would exert a strong predation pressure on these invertebrates.Key words: Cancer irroratus, rock crabs, predation, population density, kelp

scholarly journals SIZE COMPOSITION AND FECUNDITY OF THE ROCK CRAB GRAPSUS GRAPSUS (LINNAEUS, 1758) IN THE ISLANDS OF NAVACHISTE BAY, SINALOA, MEXICO

2020 ◽  
Vol 67 (1) ◽  
Author(s):  
Yecenia Gutierrez Rubio ◽  
Juan Francisco Arzola Gonzalez ◽  
Jorge Saul Ramirez Perez ◽  
Guillermo Rodriguez Dominguez ◽  
Raul Perez Gonzalez ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Carapace Width ◽  
Size Composition ◽  
Significant Difference ◽  
Average Fecundity ◽  
Rock Crab ◽  
Gravid Females

The present study analysed the size composition and fecundity of Grapsus grapsus (Linnaeus, 1758) in the intertidal regions of Guasayeye, La Ventana and San Lucas islands in Navachiste Bay, Sinaloa, Mexico. Samples were collected from November 2017 to October 2018 with a bimonthly periodicity and sampling stations were established in each island. Crab samples were collected randomly at nocturnal low tide. Sex of the crabs was determined and carapace width (CW), length (L) and height (H) in mm, and their weight (W) in g were measured. Biometric correlations were performed. Fecundity was estimated in gravid females. The highest percentage of capture for females was 53.3% whereas for males was 46.7%; and the sex ratio was 1.15:1. The highest percentage was in San Lucas Island (41.4%) and the lowest in La Ventana (27.7%). Maximum CW (69.3 mm) and weight (137.5 g) were recorded in San Lucas. Island, while the lowest CW (9.3 mm) and weight (0.5 g) were recorded in Guasayeye Island. No significant difference in size (CW and W) were observed between sexes or between islands. The average fecundity for female was 9,245 eggs. A high biometric correlation was obtained (r2=0.98) between the morphometric variables and G. grapsus was found to have an isometric growth.

Some Life History Aspects of the Rock Crab, Cancer irroratus, in the Gulf of Maine

1972 ◽  
Vol 29 (10) ◽  
pp. 1479-1482 ◽  
Author(s):  
Jay S. Krouse
Keyword(s):  
Life History ◽  
Sexual Maturity ◽  
Size Range ◽  
Gulf Of Maine ◽  
Carapace Width ◽  
Early Spring ◽  
Late Winter ◽  
Early Winter ◽  
Cancer Irroratus ◽  
Rock Crab

Rock crabs, Cancer irroratus, were caught in wire lobster traps from 1968 through 1971 at Boothbay Harbor and in 1969 at Casco Bay, Maine. Females dominated the annual catches (except in Casco Bay) and width classes from 61 to 90 mm; while males were predominant above this size range. Rock crabs from Casco Bay were heavier at a given width than those from Boothbay Harbor. Soft-shelled females were caught mostly in the fall, while soft-shelled males appeared most frequently in late winter and early spring. The occurrence of newly berried females suggested that spawning (egg extrusion) took place in late fall and early winter, and hatching occurred in spring. Most female crabs attained sexual maturity between 70–80 mm carapace width, but a few matured at widths less than 70 mm.

Size At Maturity and Sex Ratio of Arcitalitrus Dorrieni (Hunt, 1925) (Amphipoda, Talitridae) At Two Sites in County Galway, Ireland

Crustaceana ◽  
1997 ◽  
Vol 70 (6) ◽  
pp. 676-693
Author(s):  
Thomas Bolger ◽  
Rory P. O'Hanlon
Keyword(s):  
Sex Ratio ◽  
Northern Hemisphere ◽  
General Pattern ◽  
Breeding Period ◽  
Amphipod Species ◽  
Size At Maturity ◽  
Anthropogenic Dispersal ◽  
Deciduous Woodland

AbstractAnthropogenic dispersal has led to the introduction of several terrestrial amphipod species to the northern hemisphere. One such species, Arcitalitrus dorrieni (Hunt, 1925), a native of Australasia, is now found in several woodland sites in Ireland and Britain. Aspects of the biology of A. dorrieni were investigated in County Galway over a period of two years and compared between a "typical" mixed deciduous woodland habitat and a more "atypical" coniferous woodland habitat. At both sites, statistically significant differences were found between summer (Aug.-Sep.) size at maturity and winter (Jan.-Apr.) size at maturity, i.e., females were mature at smaller sizes in summer than in winter. Between-site comparisons of August-September data for both years showed that females were mature at a significantly smaller size at the mixed deciduous woodland site. A sex ratio biased in favour of females was recorded on all but one sampling date at each site, though on some dates this bias was not significant. The change in cohort sex ratio at both sites was quite distinct and exhibited the same general pattern. During the recruitment of each cohort, the ratio was biased towards males. As the cohort increased in length, however, the ratio changed to a bias in favour of females, so that by the time a particular cohort entered its breeding period the following year, it was biased firmly in favour of females. Possible reasons for the observed patterns are discussed.

scholarly journals Population biology of the crab Armases angustipes (Crustacea, Decapoda, Sesarmidae) at Brazilian tropical coast

2014 ◽  
Vol 104 (2) ◽  
pp. 150-161 ◽  
Author(s):  
Marina de Sá Leitão C. de Araújo ◽  
Deusinete de O. Tenório ◽  
Daniela da S. Castiglioni
Keyword(s):  
Population Structure ◽  
Sexual Dimorphism ◽  
Sex Ratio ◽  
Population Biology ◽  
Carapace Width ◽  
Reproductive Activity ◽  
Coastal Regions ◽  
Phytoplankton Productivity ◽  
Number Of Individuals ◽  
Tropical Coast

The semi terrestrial crabs are important elements of the fauna of coastal regions. The aim of this study was to analyze the population structure of Armases angustipes (Dana, 1852) at estuaries of the Ariquindá River, considered a non impacted area, and Mamucabas River, considered a few impacted area, on the south coast of state of Pernambuco, Brazil. The species occurred in all months of the year. The number of individuals per month varied, being higher in the months of transition between the seasons. This is probably due to significant seasonal variations of air and burrow temperature and burrow salinity. There was no sexual dimorphism in size of A. angustipes in the mangrove of Ariquindá River, but males were larger than females in the mangrove of Mamucabas River. In both estuaries, the sex ratio did not differ from Mendelian proportion, but showed a deviation for females. The analysis of temporal variation in sex ratio showed significant differences in some months of the year. These variations are due to cyclical events that act distinctly on each sex. In both estuaries, size classes of carapace width were equally represented by both sexes. The ovigerous females of A. angustipes occurred only in some months of the year, especially in summer, in both estuaries. Probably the high phytoplankton productivity observed in summer favors the reproductive activity, since these algae serve as food for the larvae. Specimens of the population of Rio Ariquindá are largest and wider than those of Mamucabas River. This fact, associated with the low abundance of crabs and the lower frequency of ovigerous females observed in Mamucabas River, is an indication that this population may be influenced by the environmental impacts that this estuary has received.

scholarly journals A multivariate study of variation in two species of rock crab of the genus Leptograpsus

1974 ◽  
Vol 22 (3) ◽  
pp. 417 ◽  
Author(s):  
NA Campbell ◽  
RJ Mahon
Keyword(s):  
Carapace Length ◽  
Carapace Width ◽  
The Body ◽  
Canonical Variate ◽  
Multivariate Approach ◽  
Maximum Width ◽  
Multivariate Study ◽  
Rock Crab ◽  
Males And Females ◽  
Colour Form

A multivariate approach has been used to study morphological variation in the blue and orange-form species of rock crab of the genus Leptograpsus. Objective criteria for the identification of the two species are established, based on the following characters: width of the frontal region of the carapace; width of the posterior region of the carapace (rear width); length of the carapace along the midline; maximum width of the carapace; and the depth of the body. The first canonical variate, which differentiates between the two species, represents a contrast between the carapace width relative to the width of the front lip and the depth of the body; the blue-form species has a greater relative carapace width than has the orange form. The second canonical variate, which presents a contrast between the rear width and the carapace length, identifies males and females within each species; males have a greater relative carapace length than have females. All individuals, including 20 not used in the study, were correctly identified for colour form. The clear separation of the blue and orange forms achieved by canonical analysis supports the previously determined specific status of the two forms.

Mating Behavior of the Rock Crab, Cancer irroratus

1978 ◽  
Vol 35 (10) ◽  
pp. 1385-1388 ◽  
Author(s):  
R. W. Elner ◽  
A. B. Stasko
Keyword(s):  
Key Words ◽  
Mating Behavior ◽  
Cancer Irroratus ◽  
Rock Crab ◽  
Laboratory Tank

A pair of rock crabs, Cancer irroratus, in mating embrace an hour after being placed in a laboratory tank, was observed intermittently until ecdysis of the female and copulation of the pair, and then until escape of the female 27 d after ecdysis. When separated from the mating embrace, the hard-shelled female sought out the male. Approach of female ecdysis was indicated by protrusion of a soft spherical bulge at the rear of the epimeral line. Details of the immediate pre- and postcopulatory behavior were observed continuously from 26 min before to 150 min after copulation. The female was first noted separated from the male 7 h after copulation. Periods of separation increased until mating interactions were completely abandoned 5 d after copulation. A second pair subsequently observed confirmed the above. Mating embrace was also observed between a hard-shelled male and a hard-shelled female that already had sperm plugs. Key words: Crustacea, crabs, copulation, molt indicators

scholarly journals Contrasting recruitment seasonality of sea urchin species in Gran Canaria, Canary Islands (eastern Atlantic)

2014 ◽  
Vol 15 (3) ◽  
pp. 475 ◽  
Author(s):  
S. GARCIA-SANZ ◽  
P. G. NAVARRO ◽  
F. TUYA
Keyword(s):  
Community Structure ◽  
Seasonal Variation ◽  
Sea Urchin ◽  
Sea Urchins ◽  
Late Summer ◽  
Paracentrotus Lividus ◽  
Abundant Species ◽  
Late Winter ◽  
Gran Canaria ◽  
Arbacia Lixula

Despite sea-urchins can play an important role affecting the community structure of subtidal bottoms, factors controlling the dynamics of sea-urchin populations are still poorly understood. We assessed the seasonal variation in recruitment of three sea-urchin species (Diadema africanum, Paracentrotus lividus and Arbacia lixula) at Gran Canaria Island (eastern Atlantic) via monthly deployment of artificial collectors throughout an entire annual cycle on each of four adjacent habitat patches (seagrasses, sandy patches, ‘urchin-grazed’ barrens and macroalgal-dominated beds) within a shallow coastal landscape. Paracentrotus lividus and A. lixula had exclusively one main recruitment peak in late winter-spring. Diadema africanum recruitment was also seasonal, but recruits appeared in late summer-autumn, particularly on ‘urchin-grazed’ barrens with large abundances of adult conspecifics. In conclusion, this study has demonstrated non-overlapping seasonal recruitment patterns of the less abundant species (P. lividus and A. lixula) with the most conspicuous species (D. africanum) in the study area.

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