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.

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 Life History and Immature Stages of Synergus pacificus McCracken and Egbert (Hymenoptera: Cynipidae)

1965 ◽  
Vol 97 (2) ◽  
pp. 185-188 ◽  
Author(s):  
David Evans
Keyword(s):  
British Columbia ◽  
Life History ◽  
Pacific Coast ◽  
Immature Stages ◽  
Central California ◽  
Larval Stages ◽  
The Pacific

AbstractSynergus pacificus McCracken and Egbert (Hymenoptera: Cynipidae) is an inquiline of oak gall cynipids in the Pacific Coast area from southern British Columbia to central California. Approximately 1,000 specimens were examined during the course of this study. Descriptions of the egg and larval stages are given, and information on life history and ecology is presented.

A scanning electron microscopic study of the veliger larvae of the scallop argopecten purpuratus

1988 ◽  
Vol 46 ◽  
pp. 284-285
Author(s):  
G.C. Bellolio ◽  
K.S. Lohrmann ◽  
E.M. Dupré
Keyword(s):  
Morphological Description ◽  
Electron Microscopic ◽  
Larval Stages ◽  
Scanning Electron Microscopic Study ◽  
The Pacific ◽  
Argopecten Purpuratus ◽  
Veliger Larvae ◽  
20 Nm ◽  
Ethanol Series ◽  
Scanning Electron

Argopecten purpuratus is a scallop distributed in the Pacific coast of Chile and Peru. Although this species is mass cultured in both countries there is no morphological description available of the development of this bivalve except for few characterizations of some larval stages described for culture purposes. In this work veliger larvae (app. 140 pm length) were examined by the scanning electron microscope (SEM) in order to study some aspects of the organogenesis of this species.Veliger larvae were obtained from hatchery cultures, relaxed with a solution of MgCl2 and killed by slow addition of 21 glutaraldehyde (GA) in seawater (SW). They were fixed in 2% GA in calcium free artificial SW (pH 8.3), rinsed 3 times in calcium free SW, and dehydrated in a graded ethanol series. The larvae were critical point dried and mounted on double scotch tape (DST). To permit internal view, some valves were removed by slightly pressing and lifting the tip of a cactus spine wrapped with DST, The samples were coated with 20 nm gold and examined with a JEOL JSM T-300 operated at 15 KV.

Experiments on Oral Secretion of the Rocky Mountain Wood Tick, Dermacentor andersoni Stiles (Acarina: Ixodidae)

1957 ◽  
Vol 89 (1) ◽  
pp. 1-5 ◽  
Author(s):  
J. D. Gregson
Keyword(s):  
British Columbia ◽  
Pacific Northwest ◽  
Rocky Mountain ◽  
Dermacentor Variabilis ◽  
Oral Secretion ◽  
Amblyomma Maculatum ◽  
Dermacentor Andersoni ◽  
The Pacific ◽  
Tick Paralysis ◽  
Rocky Mountain Wood Tick

Tick paralysis continues to be one of the most baffling and fascinating tickborne diseases in Canada. It was first reported in this country by Todd in 1912. Since then about 250 human cases, including 28 deaths, have been recorded from British Columbia. Outbreaks in cattle have affected up to 400 animals at a time, with losses in a herd as high as 65 head. Although the disease is most common in the Pacific northwest, where it is caused by the Rocky Mountain wood tick, Dermacentor andersoni Stiles, it has lately been reported as far south as Florida and has been produced by Dermacentor variabilis Say, Amblyomma maculatum Koch, and A. americanum (L.) (Gregson, 1953). The symptoms include a gradual ascending symmetrical flaccid paralysis. Apparently only man, sheep, cattle, dogs, and buffalo (one known instance) are susceptible, but even these may not necessarily be paralysed.

Redescription of Mugil setosus Gilbert 1892 with comments on the occurrence of Mugil curema Valenciennes 1836 in the Pacific Ocean (Teleostei: Perciformes: Mugilidae)

Zootaxa ◽  
2019 ◽  
Vol 4671 (3) ◽  
pp. 396-406
Author(s):  
RICARDO BRITZKE ◽  
NAÉRCIO A. MENEZES ◽  
MAURO NIRCHIO
Keyword(s):  
Pacific Ocean ◽  
Pacific Coast ◽  
The Third ◽  
Dorsal Fin ◽  
The Pacific ◽  
Fin Rays ◽  
The Pacific Ocean ◽  
The Western Pacific ◽  
Pectoral Fin Rays ◽  
Pelvic Fin

Mugil setosus Gilbert 1892 was originally described by Gilbert based on specimens from Clarion Island, in the western and most remote of the Revillagigedo Islands, about 1,000 km off the western Pacific coast of Mexico. Examination of the type of material and recently collected specimens from Ecuador and Peru, resulted in the redescription provided herein. Diagnostic characters of the species were mainly: tip of the pelvic fin reaching beyond the vertical through the base of the third dorsal-fin spine, the pectoral-fin rays with ii+13–14 rays, the anterodorsal tip of second (soft) dorsal fin uniformly dark, and an external row of larger teeth, and more internally a patch of scattered smaller teeth, visible mainly in adults 150 mm SL. The expansion of geographic distribution of Mugil setosus and occurrence of Mugil curema Valenciennes 1836 in the Pacific Ocean are discussed. 

scholarly journals Conservation Evaluation of the Pacific Population of Dwarf Woollyheads, Psilocarphus brevissimus var. brevissimus, in Canada

2006 ◽  
Vol 120 (2) ◽  
pp. 163
Author(s):  
George W. Douglas ◽  
Jenifer L. Penny ◽  
Ksenia Barton
Keyword(s):  
British Columbia ◽  
Coalbed Methane ◽  
Groundwater Levels ◽  
Gas Drilling ◽  
Pacific Population ◽  
South Central ◽  
The Pacific ◽  
Recreational Vehicles ◽  
Forest Openings ◽  
Conservation Evaluation

In Canada, Dwarf Woolly-heads, Psilocarphus brevissimus var. brevissimus, is restricted to the Similkameen River valley, south of Princeton in southwestern British Columbia and the extreme southeast and southwest corners of Alberta and Saskatchewan, respectively. This paper deals with the three British Columbia populations which represent the northwestern limit of the species which ranges from south-central British Columbia, southward in the western United States to Montana, Idaho, Washington, Oregon, Nevada, Utah, Wyoming, California and Baja California, Mexico. In British Columbia, P. brevissimus is associated with calcareous vernal pools and ephemeral pond edges in large forest openings. This habitat is rare in the area the few existing populations could easily be extirpated or degraded through slight changes in groundwater levels, coalbed methane gas drilling, housing development or recreational vehicles.

Studies on the life-history of Bunostomum phlebotomum (Railliet, 1900), a hookworm parasite of cattle

Parasitology ◽  
1946 ◽  
Vol 37 (3-4) ◽  
pp. 192-201 ◽  
Author(s):  
J. F. A. Sprent
Keyword(s):  
Infective Larva ◽  
Stage Larva ◽  
Fourth Stage ◽  
Larval Stages ◽  
The Third ◽  
Third Stage ◽  
History Of ◽  
Time Required ◽  
Cutaneous Blood ◽  
Fourth Stage Larva

A description is given of the processes of copulation, formation of the egg and spermatozoon, cleavage, embryogeny and hatching in B. phlebotomum. These processes were found to be essentially similar to those in other strongyle nematodes.The anatomy of the first three larval stages is described and the observations of Conradi & Barnette (1908) and Schwartz (1924) were largely confirmed.Penetration of the skin of calves by the infective larva was observed histologically. The larvae were found to have reached the dermis within 30 min. and to have penetrated the cutaneous blood vessels within 60 min. of application to the skin. The larvae were found in the lung where the third ecdysis was in progress 10 days after penetration of the skin. A description is given of the growth of the third-stage larva in the lung, the changes which take place during the third ecdysis, and the anatomy of the fourth-stage larva.The fourth-stage larvae exsheath in the lungs and travel to the intestine. After a period of growth in which sexual differentiation takes place, the fourth ecdysis occurs and the adult parasite emerges. The time required for the attainment of maturity was found to be somewhere between 30 and 56 days after penetration of the skin.This paper was written at the Ministry of Agriculture and Fisheries Veterinary Laboratories, Wey-bridge, and the writer would like to express his gratitude to the Director, Prof. T. Dalling, also to Dr W. R. Wooldridge, chairman of the Council of the Veterinary Educational Trust for their help and encouragement. The writer's thanks are also due to Dr H. A. Baylis, Prof. R. T. Leiper and Dr E. L. Taylor for their advice and help on technical points, and to Mr R. A. O. Shonekan, African laboratory assistant, for his able co-operation.

Population Structure of Dungeness Crab (Cancer magister) in British Columbia

2008 ◽  
Vol 27 (4) ◽  
pp. 901-906 ◽  
Author(s):  
Terry D. Beacham ◽  
Janine Supernault ◽  
Kristina M. Miller
Keyword(s):  
British Columbia ◽  
Population Structure ◽  
Dungeness Crab ◽  
Cancer Magister

1999 Pacific Northwest Labor History Association Conference

2000 ◽  
Vol 57 ◽  
pp. 117-119 ◽  
Author(s):  
Daniel Jacoby
Keyword(s):  
British Columbia ◽  
Pacific Northwest ◽  
Labor History ◽  
Definitive Answer ◽  
Preferable Alternative ◽  
The Pacific ◽  
The Moment ◽  
Academic Conferences

I cannot provide a definitive answer to those of us pondering what the best alternative to capitalism is, but after attending the Pacific Northwest Labor History Association (PNLHA) Conference in Westminster, British Columbia, over the weekend of May 28–30, 1999, I can tell you that this is certainly a preferable alternative to standard academic conferences. As usual, the PNLHA was able to produce a cadre of historians (from the trades as well as academia), active unionists, and old-timers whose memories are as tapable as a keg of beer. Although the association designates labor history as its subject, newly elected President Ross Rieder likes to say, “History ends the moment before now.”

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