The impact of yellow shore crabs,Hemigrapsus oregonensis, on Early Benthic Phase dungeness crabs,Cancer magister, in intertidal oyster shell mitigation habitat

Estuaries ◽  
2004 ◽  
Vol 27 (4) ◽  
pp. 699-715 ◽  
Author(s):  
Eileen P. Visser ◽  
P. Sean McDonald ◽  
David A. Armstrong
Keyword(s):  
Oyster Shell ◽  
Cancer Magister ◽  
Shore Crabs ◽  
Hemigrapsus Oregonensis ◽  
Dungeness Crabs ◽  
The Impact

scholarly journals Long-term change in the parasite burden of shore crabs ( Hemigrapsus oregonensis and Hemigrapsus nudus ) on the northwestern Pacific coast of North America

2021 ◽  
Vol 288 (1945) ◽  
pp. 20203036
Author(s):  
Jessica Quinn ◽  
Sarah Lee ◽  
Duncan Greeley ◽  
Alyssa Gehman ◽  
Armand M. Kuris ◽  
...  
Keyword(s):  
Parasite Burden ◽  
Shore Crab ◽  
Northwestern Pacific ◽  
Intermediate Hosts ◽  
Term Change ◽  
Shore Crabs ◽  
Living Species ◽  
Hemigrapsus Oregonensis ◽  
Over Time

The abundances of free-living species have changed dramatically in recent decades, but little is known about change in the abundance of parasitic species. We investigated whether populations of several parasites have shifted over time in two shore crab hosts, Hemigrapsus oregonensis and Hemigrapsus nudus, by comparing the prevalence and abundance of three parasite taxa in a historical dataset (1969–1970) to contemporary parasite abundance (2018–2020) for hosts collected from 11 intertidal sites located from Oregon, USA, to British Columbia, Canada. Our data suggest that the abundance of the parasitic isopod Portunion conformis has varied around a stable mean for the past 50 years. No change over time was observed for larval acanthocephalans. However, larval microphallid trematodes increased in prevalence over time among H. oregonensis hosts, from a mean of 8.4–61.8% between the historical and contemporary time points. The substantial increase in the prevalence of larval microphallid trematodes could be owing to increased abundances of their bird final hosts, increased production of parasite infective stages by snail intermediate hosts or both. Our study highlights the variability among parasite species in their temporal trajectories of change.

scholarly journals Ventilation, Oxygen Uptake and Haemolymph Oxygen Transport, Following Enforced Exhausting Activity in the Dungeness Crab Cancer Magister

1979 ◽  
Vol 80 (1) ◽  
pp. 271-285 ◽  
Author(s):  
B. R. McMAHON ◽  
D. G. McDONALD ◽  
C. M. WOOD
Keyword(s):  
Cardiac Output ◽  
Oxygen Uptake ◽  
Oxygen Transport ◽  
Lactate Concentration ◽  
Fold Increase ◽  
Oxygen Extraction ◽  
Oxygen Release ◽  
Cancer Magister ◽  
Metabolic Scope ◽  
Dungeness Crabs

Scaphognathite and heart-pumping frequencies, ventilation volume, cardiac output, oxygen uptake and oxygen transport by haemolymph have been studied in unrestrained Dungeness crabs (Cancer magister) before, immediately after, and during recovery from 20 min of enforced exhausting activity. Exercise increased oxygen uptake 4-fold. This increase was achieved by more than 2-fold elevation of both ventilation volume and cardiac output and by greater participation of haemocyanin in oxygen delivery. The elevated ventilation volume resulted entirely from an increase in scaphognathite pumping frequency, while the rise in cardiac output resulted largely from increase in stroke volume. Prior to exercise haemocyanin accounts for less than 50% of the oxygen delivered to the tissues. Following exercise this increases to over 80%, the additional oxygen release being mediated by a depression of prebranchial oxygen tension and a substantial Bohr effect resulting from build up of lactate ion in the haemolymph and subsequent fall in pH. These changes allowed % oxygen extraction from branchial water to be maintained at 28% despite a 2-fold increase in ventilation volume, and allowed an increase in %. oxygen extraction by the tissues. Despite these changes oxygen supply fell below demand during exercise, and considerable anaerobic metabolism resulted, as evidenced by a 9-fold increase in haemolymph lactate concentration. The resulting oxygen debt required 8–24 h for repayment. Aerobic metabolic scope, and mechanisms of increasing oxygen uptake and transport in this crab are compared with those of a range of fish species.

First Cohort of Young-of-the-year Dungeness Crab, Cancer magister, Reduces Abundance of Subsequent Cohorts in Intertidal Shell Habitat

1993 ◽  
Vol 50 (10) ◽  
pp. 2100-2105 ◽  
Author(s):  
Miriam Fernandez ◽  
David Armstrong ◽  
Oscar Iribarne
Keyword(s):  
Laboratory Experiments ◽  
Oyster Shell ◽  
Field Observations ◽  
Dungeness Crab ◽  
Cancer Magister ◽  
First Instar ◽  
Alternative Hypotheses ◽  
Young Of The Year

Arrival and settlement of successive cohorts of Dungeness crab, Cancer magister, megalopae were observed in Grays Harbor, Washington, in 1991. The first cohort of megalopae entered the estuary between May 15 and 20 and settled in ("occupied") previously constructed artificial, intertidal oyster shell habitats at densities ranging from 155 to 196 first instar juvenile (J1) crabs∙m−2. Subsequently, a second set of shell habitats was constructed that did not contain crabs of the first cohort ("unoccupied"). Between June 15 and 18, when crabs of the first cohort were a mix of second and third instars, a second cohort of megalopae settled in both occupied and unoccupied shell habitat at respective J1 crab densities of 9–37 and 168–298 crabs∙m−2. The possible roles of cannibalism, competition, and conspecific avoidance are proposed as alternative hypotheses to explain significantly lower density of the second cohort in shell habitats previously occupied by larger conspecifics of the first cohort. Based on laboratory experiments, we suggest that cannibalism is a plausible explanation of our field observations.

Heat-Pasteurization Process for Inactivation of Nonproteolytic Types of Clostridium botulinum in Picked Dungeness Crabmeat

1997 ◽  
Vol 60 (8) ◽  
pp. 928-934 ◽  
Author(s):  
M. E. PETERSON ◽  
G. A. PELROY ◽  
F. T. POYSKY ◽  
R. N. PARANJPYE ◽  
F. M. DONG ◽  
...  
Keyword(s):  
Clostridium Botulinum ◽  
Temperature Treatment ◽  
Heat Processing ◽  
Type B ◽  
Cancer Magister ◽  
Enrichment Medium ◽  
Heat Resistant ◽  
Heat Pasteurization ◽  
D Values ◽  
Dungeness Crabs

Development of a heat-pasteurization process is described for picked meat of Dungeness crabs (Cancer magister) contained in oxygen-impermeable flexible pouches, For each time-temperature treatment, 30 samples, each inoculated with an equal mixture of three strains of C. botulinum nonproteolytic type B, for a total of 107 spores, provided the basis for calculation of the thermal resistance (a 7D process). Following heat processing, the crabmeat was removed from the pouches and transferred to enrichment medium where it was incubated anaerobically for 150 days. Endpoints at which spores survived were determined by the presence of toxin in the enrichment medium. Process times ranged from 90 min at 88.9°C to 20.3 min at 94.4°C. D values (the time at each temperature required to reduce the inoculum by 1 log) ranged from 12.9 for the 88.9°C process to 2.9 for the 94.4°C process. The relative sterilization value, F0 was .054 and the pasteurization value, , was 240. This pasteurization process safely extends refrigerated shelf life by inactivating spores of Clostridium botulinum nonproteolytic types B, E, and F and also non-spore-forming pathogens such as Listeria monocytogenes. The process does not, however, inactivate the heat-resistant proteolytic strains of C. botulinum or other more heat-resistant spore-formers. The packages and master cartons of the pasteurized product, therefore, should be labeled “Keep refrigerated—Continuous refrigeration below 38°F (3.3°C) required.”

Quantifying Changes in British Columbia Dungeness Crab (Cancer magister) Landings Using Intervention Analysis

1986 ◽  
Vol 43 (3) ◽  
pp. 634-639 ◽  
Author(s):  
D. Noakes
Keyword(s):  
British Columbia ◽  
Time Series Data ◽  
Statistical Tests ◽  
Series Data ◽  
Dungeness Crab ◽  
Intervention Model ◽  
Cancer Magister ◽  
Abrupt Decrease ◽  
The Impact ◽  
Future Management

Natural or man-induced interventions may cause temporary or permanent changes in the behaviour of biological systems. To determine the impact of future management decisions, it is first necessary to quantify the effects of past interventions on the system. Only then can rational decisions be made so as to ensure that the desired response is achieved. However, time series data are often autocorrelated and this precludes the use of standard statistical tests. The linear stochastic intervention model outlined in this paper takes this autocorrelation into account and provides a procedure for quantifying the impacts of particular interventions. This model is employed to determine if there has been a significant abrupt decrease in Dungeness crab (Cancer magister) landings in British Columbia.

A ciliate infection (Paranophrys sp.) in laboratory-held Dungeness crabs, Cancer magister

1981 ◽  
Vol 37 (2) ◽  
pp. 201-209 ◽  
Author(s):  
David A. Armstrong ◽  
Eugene M. Burreson ◽  
Albert K. Sparks
Keyword(s):  
Cancer Magister ◽  
Dungeness Crabs

Does intense fishing on males impair mating success of female Dungeness crabs

1997 ◽  
Vol 54 (3) ◽  
pp. 655-669 ◽  
Author(s):  
D G Hankin ◽  
T H Butler ◽  
P W Wild ◽  
Q -L Xue
Keyword(s):  
Mating Success ◽  
Egg Production ◽  
Carapace Width ◽  
Minimum Size ◽  
Cancer Magister ◽  
Worst Case ◽  
Mature Adult ◽  
Commercial Harvest ◽  
Size Limits ◽  
Dungeness Crabs

Commercial capture of female Dungeness crabs, Cancer magister, is prohibited and minimum size limits for commercial harvest of male crabs are designed to allow most males to mate at least once before capture. Annual exploitation rates often exceed 90%, however, and the resulting scarcity of large males might reduce mating success among large females. We present new data regarding (i) sizes of male and female crabs collected in premating embraces, (ii) carapace width frequencies of female Dungeness crabs, (iii) presence of sperm plugs and sperm, and (iv) fecundity. Minimum carapace width of hard-shelled mating males typically exceeds postmolt carapace width of soft-shelled females (i), but female Dungeness crabs exceeding the minimum legal size of males usually account for less than 5% of mature adult female crabs (ii), and sublegal-sized males actively participate in mating (i). Remnants of sperm plugs, definitive indicators of mating, were found in 97.5% of recently molted large females (iii), suggesting that virtually all molting females mate regardless of size. On the basis of (ii) and (iv), hypothetical worst-case calculations, assuming that no large females could find mates, suggest that total egg production would be reduced by no more than 2-25% among molting female crabs.

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