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.

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.

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

scholarly journals Distribution of the Pacific/North America motion in the Queen Charlotte Islands-S. Alaska plate boundary zone

2003 ◽  
Vol 30 (14) ◽  
Author(s):  
Stéphane Mazzotti ◽  
Roy D. Hyndman ◽  
Paul Flück ◽  
Alex J. Smith ◽  
Michael Schmidt
Keyword(s):  
North America ◽  
Plate Boundary ◽  
Boundary Zone ◽  
Queen Charlotte Islands ◽  
The Pacific ◽  
Plate Boundary Zone

The Parasitic Rhizocephalan Barnacle Sacculina Carcini in Crabs of the Forth Estuary, Scotland

1998 ◽  
Vol 78 (2) ◽  
pp. 665-667 ◽  
Author(s):  
S. Mathieson ◽  
A.J. Berry ◽  
S. Kennedy
Keyword(s):  
Carapace Width ◽  
High Tide ◽  
Carcinus Maenas ◽  
Size Class ◽  
Infection Rates ◽  
Lower Estuary ◽  
Male And Female ◽  
Sacculina Carcini ◽  
Middle Estuary

In the Forth Estuary, Scotland, parasitic rhizocephalan barnacle Sacculina carcini externae or scars occurred on 64% of Carcinus maenas from the subtidal channel of the middle estuary. These became more frequent downstream, infecting 46·9% in the lower estuary basin. Male and female crabs were infected equally, and infection rates in low-tide samples did not differ from high-tide. The parasites occurred most frequently on crabs of 40–50 mm carapace width (CW) rather than the modal crab size class of 50–60 mm. Downstream, proportionately more smaller than larger crabs bore parasites whereas, further upstream, more larger than smaller crabs bore parasites. There is evidence for the annual appearance of new externae in July-October, especially in the lower estuary basin, followed by their growth and loss after about a year.

COUPLING BEHAVIOUR OF THE MIGRATORY GRASSHOPPER, MELANOPLUS SANGUINIPES (ORTHOPTERA: ACRIDIDAE)

1972 ◽  
Vol 104 (6) ◽  
pp. 873-879 ◽  
Author(s):  
R. Pickford ◽  
C. Gillott
Keyword(s):  
Sexual Activity ◽  
Melanoplus Sanguinipes ◽  
Male And Female ◽  
Female Mating ◽  
Unfavourable Weather ◽  
High Level

AbstractThe mechanics of coupling in Melanoplus sanguinipes (Fabr.) are described and differences between some species of Acrididae discussed. A high level of coupling activity was revealed with the most active male and female mating 56 and 46 times, respectively. In addition, multiple daily matings, to a maximum of five, were common. The majority of copulations occurred during the morning in both laboratory and field; however, in the latter, unfavourable weather restricted sexual activity. Coupling did not appear to occur at random; significant preferences were shown by certain males for certain females.

Tingupa tlingitorum, n. sp., a new milliped from Haines, Alaska, USA, with notes on the generic distribution and a revised key to species (Chordeumatida: Tingupidae)

Zootaxa ◽  
2007 ◽  
Vol 1393 (1) ◽  
pp. 53-59 ◽  
Author(s):  
WILLIAM A. SHEAR ◽  
ROWLAND M. SHELLEY
Keyword(s):  
British Columbia ◽  
Distribution Map ◽  
Key To Species ◽  
Northern Limit ◽  
Male And Female ◽  
Queen Charlotte Islands ◽  
The Family ◽  
Generic Distribution

Tingupa tlingitorum n. sp. (Diplopoda: Chordeumatida: Tingupidae) is proposed for male and female millipeds from Haines, Alaska, USA. It constitutes the first Alaskan record of the family and third of the order, and represents generic and familial range extensions of ca. 1,050 mi (1,680 km) from the previous northern limit in Oregon. Tingupa sp. is also reported from Idaho, the first generic and familial records from this state, and the Queen Charlotte Islands, the first records for both Canada and British Columbia. A revised key to species and a new familial distribution map are presented.

scholarly journals Verticillium Wilt in Spinach Seed Production

Plant Disease ◽  
2005 ◽  
Vol 89 (1) ◽  
pp. 4-11 ◽  
Author(s):  
Lindsey J. du Toit ◽  
Mike L. Derie ◽  
Pablo Hernandez-Perez
Keyword(s):  
United States ◽  
Pacific Northwest ◽  
Seed Production ◽  
Verticillium Wilt ◽  
Spinacia Oleracea ◽  
Seed Transmission ◽  
The United States ◽  
Male And Female ◽  
Systemic Movement ◽  
The Pacific

There are no previous reports of Verticillium wilt in fresh and processing spinach (Spinacia oleracea) crops in the United States. In 2002, a hybrid spinach seed crop in the Pacific Northwest developed late-season wilt symptoms. Assays of the harvested seed and stock seed of the male and female parents revealed 59.5, 44.0, and 1.5%, respectively, were infected with Verticillium dahliae. Assays of 13 stock or commercial seed lots grown in 2002 and 62 commercial lots harvested in 2003 in Denmark, Holland, New Zealand, and the United States revealed the prevalence of Verticillium spp. in commercial spinach seed. Sixty-eight lots (89%) were infected with Verticillium spp. at incidences ranging from 0.3 to 84.8%. Five spinach seed isolates of V. dahliae were pathogenic on each of three spinach cultivars by root-dip inoculation. V. dahliae was detected on 26.4% of the seed from 7 of 11 inoculated plants but on none of the seed from 6 control plants, demonstrating systemic movement of V. dahliae. Seed-to-seed transmission was also demonstrated by planting naturally infected seed lots. This is the first report of Verticillium wilt of spinach in the primary region of spinach seed production in the United States.

scholarly journals Stock Status of Blue Swimming Crab (Portunus pelagicus Linnaeus, 1758) in Tiworo Strait Waters, Southeast Sulawesi, Indonesia

2020 ◽  
Vol 25 (2) ◽  
pp. 85-90
Author(s):  
Yustika Permatahati Intan Permatahati ◽  
Nila Nikmatia Bugis ◽  
La Sara ◽  
Tezza Fauzan Hasuba Hasuba
Keyword(s):  
Carapace Width ◽  
Growth Patterns ◽  
Fishing Ground ◽  
Swimming Crab ◽  
Portunus Pelagicus ◽  
Male And Female ◽  
Gonad Maturity ◽  
Stock Status ◽  
Spawning Potential Ratio ◽  
Very High

The blue swimming crab (BSC) fishery in Tiworo Strait has been heavily exploited since two decades ago when its worldwide demand and price was very high. Study on population aspects of this organism in this waters is limited. The aim of present study was to investigate growth patterns, population stock status, and size at first gonad maturity of Portunus pelagicus. One of the main fishing ground of BSC around Tiworo Strait waters is at Bangko and Gala Islands. Samples of BSC were taken monthly using gillnet and collapsible trap. Each sample taken was identified its sex, measured its carapace width, and weighed. Data collected from fishing ground of BSC were analyzed to find out growth patterns, population stock status using spawning potential ratio (SPR) method, and the first gonad maturity (CW50). The results of study showed that growth patterns of BSC male and female following isometric growth patterns (b=0) (P<0.05). It was found out that SPR of BSC from both fishing ground was 22.46% and 23.71%, respectively which indicates that population stock status of BSC in Tiworo strait waters is “moderate level” (SPR > 20%). The size at first gonad maturity (CW50) was attained at carapace width of 9.16 cm for male and 10.16 cm for female. Those imply that BSCs allowed to be caught should be >10 cm. 

Premating and Mating Behavior of the Dungeness Crab (Cancer magister Dana)

1966 ◽  
Vol 23 (9) ◽  
pp. 1319-1323 ◽  
Author(s):  
C. Dale Snow ◽  
John R. Neilsen
Keyword(s):  
Mating Behavior ◽  
Dungeness Crab ◽  
Continuous Observation ◽  
Cancer Magister ◽  
Male And Female ◽  
Male Crab

A male and female Dungeness crab (Cancer magister Dana) were kept under continuous observation in an aquarium to observe the premating embrace, female ecdysis, and mating. The male held the female in premating embrace from June 10 until June 18, 1965, when she molted. The male allowed the female to reverse her position from the premating embrace, sternum to sternum, to that of female carapace to male sternum only after she became aggressive. The male never allowed the female to escape from his control while she molted. Copulation occurred 1 hr and 32 min after female ecdysis, when the new exoskeleton had firmed somewhat, and the male carried the female in a postmating embrace for 2 days.Extensive wear on the chelipeds of male crabs may reflect prolonged periods in the premating embrace and stroking of the female by the male rather than matings with several females. The male crab probably becomes aware of the female's readiness to molt by her aggressive pinching of maxillae and eyestalks.

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