THE STEROL OF THE PACIFIC CRAB, CANCER MAGISTER

1945 ◽  
Vol 10 (4) ◽  
pp. 286-287 ◽  
Author(s):  
C. ALBERT KIND ◽  
ESTELLE M. FASOLINO
Keyword(s):  
Cancer Magister ◽  
The Pacific

Maturity and Breeding of the Pacific Edible Crab, Cancer magister Dana

1960 ◽  
Vol 17 (5) ◽  
pp. 641-646 ◽  
Author(s):  
T. H. Butler
Keyword(s):  
Sexual Activity ◽  
Carapace Width ◽  
Cancer Magister ◽  
Male And Female ◽  
Breeding Activity ◽  
Queen Charlotte Islands ◽  
The Pacific

The breeding procedure of C. magister is described. Contact between the male and female in the pre-mating embrace causes marks on the exoskeletons. These "mating marks" are used as an indicator of breeding activity of male crabs. Differences in intensity of mating marks are discerned, and these are interpreted as evidence of polygamy under natural conditions.Examination of vasa deferentia and sampling of male breeding crabs has indicated that onset of maturity in the Queen Charlotte Islands occurs at a carapace width of about 110 mm, or at approximately three years of age. However, sexual activity is not appreciable until the width is about 140 mm.Female crabs are mature at a carapace width of 100 mm, at about two years.

Ionic regulation in the Pacific edible crab, Cancer magister (Dana)

1973 ◽  
Vol 51 (7) ◽  
pp. 735-743 ◽  
Author(s):  
F. R. Engelhardt ◽  
P. A. Dehnel
Keyword(s):  
Estuarine Environment ◽  
Ionic Regulation ◽  
Magnesium Ions ◽  
Cancer Magister ◽  
Sodium Potassium ◽  
Seasonal Differences ◽  
The Pacific ◽  
Calcium And Magnesium ◽  
Seasonal Acclimation

Regulation in blood and urine of chloride, sodium, potassium, calcium, and magnesium was determined for the crab, Cancer magister, collected from an estuarine environment and adapted to hypo- and hypersaline conditions. Seasonal differences in regulation were found, demonstrating seasonal acclimation. In all instances except magnesium, ions were regulated hypertonically in dilute media, and summer-adapted animals were the greater regulators. In concentrated media, ions differed with regard to the degree of regulation. Regulation of magnesium is strongly hypotonic. Size was determined not to be a factor in the regulation of ions.

Relative Growth in the Pacific Edible Crab, Cancer magister

1934 ◽  
Vol 31 (9) ◽  
pp. 1137-1139 ◽  
Author(s):  
F. W. Weymouth ◽  
D. C. G. Mackay
Keyword(s):  
Cancer Magister ◽  
Relative Growth ◽  
The Pacific

The Growth of the Pacific Edible Crab, Cancer magister Dana

1935 ◽  
Vol 1 (3) ◽  
pp. 191-212 ◽  
Author(s):  
Donald C. G. MacKay ◽  
Frank W. Weymouth
Keyword(s):  
British Columbia ◽  
Average Duration ◽  
Maximum Size ◽  
Cancer Magister ◽  
Larval Instars ◽  
Larval Stages ◽  
The Third ◽  
The Pacific ◽  
Size Of Animals ◽  
Males And Females

Approximately 20,000 measurements were made of crabs and cast exoskeletons, chiefly from Boundary bay, southern British Columbia. From size frequencies of crabs under 3 cm. seven modes have been identified as representing the early post-larval instars. Increase in size of animals in the laboratory or in live wells is significantly less than in nature, and leads to erroneous results when applied to growth. The increase per moult decreases from about 40 per cent in the early post-larval stages to about 15 per cent in males of 13.5 cm. and 10 per cent in females of 13.0 cm. Above 10 cm. the males increase more per moult. The intervals between moults become progressively longer with increasing size, and tagging experiments indicate that large crabs moult yearly. Probably to reach the maximum size, seventeen and sixteen post-larval instars are required for males and females respectively. Sexual maturity in female crabs is probably attained during the fourth or fifth year but may occur in the third or the sixth year. The legal size in British Columbia (6½ inches, or 16.5 cm.) is probably attained during the seventh or eighth year. The average duration of life is probably about eight years and the maximum age not more than ten years.

Megalopal Spatial Distribution and Stock Separation in Dungeness Crab (Cancer magister)

1993 ◽  
Vol 50 (2) ◽  
pp. 416-429 ◽  
Author(s):  
G. S. Jamieson ◽  
A. Phillips
Keyword(s):  
Dungeness Crab ◽  
Cancer Magister ◽  
Strait Of Georgia ◽  
Daily Movement ◽  
The Pacific ◽  
Juan De Fuca ◽  
The Pacific Ocean ◽  
Estuarine Flow ◽  
Juan De Fuca Strait ◽  
Outer Coast

During the day, Dungeness crab (Cancer magister) megalopae from off the outer coasts of Vancouver Island and Washington are aggregated at about 25 m whereas those from the Strait of Georgia are at about 160 m. At night, both populations of megalopae seem to be mostly in the top metre of water. Juan de Fuca Strait, which connects the Strait of Georgia to the Pacific Ocean, typically has an estuarine circulation, with outflow in the top 50–100 m and deeper inflow. Because the daylight to dark ratio when megalopae are present is about 3:1, the Strait of Georgia and outer-coast megalopae are mostly retained within their own systems by currents at their daytime depths. Occasional intrusions of outer-coast megalopae into Juan de Fuca Strait may occur when estuarine flow in the Strait temporarily breaks down following sustained, strong, southwesterly winds; such intrusions are typically restricted to the south and head of Juan de Fuca Strait, and even extensive ones do not carry megalopae far into the Strait of Georgia. The daily movement of larval crab to cold (<10 °C), deep water in the Strait of Georgia may explain, at least partially, the delay in seasonal timing of settlement and their smaller physical size at settlement compared with outer-coast megalopae.

Growth and Age Determination of the Pacific Edible Crab Cancer magister Dana

1961 ◽  
Vol 18 (5) ◽  
pp. 873-891 ◽  
Author(s):  
T. H. Butler
Keyword(s):  
British Columbia ◽  
Carapace Width ◽  
Age Groups ◽  
Age Determination ◽  
Cancer Magister ◽  
Larval Instars ◽  
Frequency Distributions ◽  
Queen Charlotte Islands ◽  
The Pacific

Of 2,820 early post-larval unsexed crabs collected by small-meshed trawl in two regions of the Queen Charlotte Islands, 1,175 were measured and the 1st and 2nd post-larval instars were identified as modes at 6.9 and 10.0 mm, respectively. Increments of 5 unsexed moulted crabs, carapace widths 6.80 to 9.96 mm, were from 36.3 to 46.5%. A total of 284 males, from 83 to 186 mm, moulted in crab traps, live-wells, and while at large as tagged specimens; 44 females, from 88 to 145 mm, moulted in traps. Using equations of regression of new carapace width on old width for both sexes and starting at the 2nd instar, average carapace widths were calculated for instars 3 to 15. In the width-frequency distributions of 8,145 crabs, separation of stages was sufficient for identification of age-groups. It is estimated that a year after hatching, males reach stage 5 or 6 (24.2 or 31.1 mm); after 2 years stage 11 or 12 (96.6 or 119.5 mm) is attained; after 3 years stage 13 (146.9 mm); after 4 years most males are in the 14th stage (176.2 mm) and above the British Columbia legal size of 165 mm; and generally after 5 years males are in stage 15 (207.5 mm). Growth of females is similar for 2 years, but afterwards is slower.

Use of Oyster Shell to Enhance Intertidal Habitat and Mitigate Loss of Dungeness Crab (Cancer magister) Caused by Dredging

1993 ◽  
Vol 50 (2) ◽  
pp. 381-390 ◽  
Author(s):  
Brett R. Dumbauld ◽  
David A. Armstrong ◽  
Trent L. McDonald
Keyword(s):  
Pacific Northwest ◽  
Large Scale ◽  
Oyster Shell ◽  
The United States ◽  
Dungeness Crab ◽  
Cancer Magister ◽  
Pacific Northwest Coast ◽  
Intertidal Crab ◽  
The Pacific ◽  
Scale 8

Juvenile Dungeness crab (Cancer magister) recruit to intertidal areas in estuaries along the Pacific Northwest coast of the United States in May and June of each year and survive best through their first summer in shell or eelgrass habitat. Experiments were initiated in Grays Harbor, Washington, to investigate the potential of using shell to enhance intertidal crab habitat as a means to augment the crab resource and mitigate losses from the subtidal population that occur during dredging. Experimental plots (225 m2) were constructed prior to crab settlement at each of three intertidal locations using three configurations of oyster shell (heavy layer, light scattering, and small piles of shell). Resulting crab densities were comparable with those found in naturally occurring shell with high numbers (20–60 crab∙m−2) observed during settlement that declined to a relatively stable density of 10 crab∙m−2 in July and August. Crab survival was highest in both heavy and pile configurations, but the heavy shell configuration remained intact the longest. This enhancement experiment has become the impetus for a large-scale (8 ha) mitigation program in 1992 as part of a dredging project completed in 1990 in Grays Harbor.

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