Therapeutic Treatment for Epibiotic Fouling on Dungeness Crab (Cancer magister) Larvae Reared in the Laboratory

1977 ◽  
Vol 34 (3) ◽  
pp. 432-436 ◽  
Author(s):  
William S. Fisher ◽  
Richard T. Nelson
Keyword(s):  
Phaeodactylum Tricornutum ◽  
Sea Water ◽  
Chemotherapeutic Agent ◽  
Larval Survival ◽  
Antibiotic Activity ◽  
Dungeness Crab ◽  
Cancer Magister ◽  
Larval Stages ◽  
Reasonable Evidence ◽  
Egg Stages

This study shows that larvae of the Dungeness crab (Cancer magister Dana) reared in the laboratory are susceptible to epibiotic microbial infestation similar to that described for eggs of the same species. Larval survival in the laboratory was increased by increased additions of antibiotics to the sea water; however, the chemotherapeutic agent, malachite green, was unsuccessful due to its toxicity to the sensitive larval stages. The addition of the diatom Phaeodactylum tricornutum was beneficial to larval survival in the light but detrimental in dark conditions, supporting the suggestion of a photosynthetic excretion from the algae capable of antibiotic activity. Chronic antibiotic treatment was observed to reduce the size of the larvae. Demonstration of larval susceptibility to epibiotic microbial infestation in the laboratory coupled with its occurrence on egg stages in nature provides reasonable evidence that the disease can occur on larval stages in nature.

Effects of the Insecticide Sevin on Various Stages of the Dungeness Crab, Cancer magister

1970 ◽  
Vol 27 (1) ◽  
pp. 93-104 ◽  
Author(s):  
David V. Buchanan ◽  
Raymond E. Millemann ◽  
Nelson E. Stewart
Keyword(s):  
Sea Water ◽  
Field Application ◽  
Dungeness Crab ◽  
Cancer Magister ◽  
Egg Hatching ◽  
Growth And Survival ◽  
Life History Stages ◽  
And Control ◽  
Control Survival ◽  
Early Larvae

Of the life-history stages of the Dungeness crab, Cancer magister, the early larvae are more sensitive to Sevin than are juveniles and adults. A concentration of 1.0 mg/liter did not affect egg hatching but prevented molting of all prezoeae to zoeae. The concentration that killed 50% of the first stage zoeae during a 96-hr exposure (96-hr EC50 for death) was estimated to be 0.01 mg/liter. Few zoeae were killed in 24 hr by 82.0 mg/liter, but the 24-hr EC50 for death within 15 days after the exposure was estimated to be 0.015 mg/liter. The 24-hr EC50 for cessation of swimming, which was not always permanent, was 0.0065 mg/liter. Survival of zoeae after 25 days exposure to concentrations of 0.0001, 0.00032, 0.001, 0.0032, and 0.01 mg/liter were 83, 60, 69, 21, and 0%, respectively, and control survival was 79%. Molting was delayed at a concentration as low as 0.0001 mg/liter.Young juvenile crabs are more sensitive to Sevin than are older juveniles or adults. The 24-hr EC50's for death or irreversible paralysis were estimated to be 0.076 and 0.35 to 0.62 mg/liter for second and ninth stage juveniles, respectively. The behavior, growth, and survival of juvenile crabs were not affected when the animals were exposed to 0.032 mg/liter of Sevin for 24 hr and then held in clean sea water for 44 days. The 24-hr and 96-hr EC50's for death or irreversible paralysis were 0.49 and 0.26 mg/liter, respectively, for adult crabs. After eating cockle clams that had just been exposed for 24 hr to 1.0, 3.2, and 10.0 mg/liter of Sevin, 22, 77, and 100% of adult crabs, respectively, were irreversibly paralyzed within 6 hr. The significance of these findings in field application of Sevin to control oyster pests and predators is discussed.

Relationships of Epibiotic Fouling and Mortalities of Eggs of the Dungeness Crab (Cancer magister)

1976 ◽  
Vol 33 (12) ◽  
pp. 2849-2853 ◽  
Author(s):  
William S. Fisher
Keyword(s):  
Ultraviolet Irradiation ◽  
Laboratory Experiments ◽  
Sea Water ◽  
Close Association ◽  
Dungeness Crab ◽  
Cancer Magister ◽  
Egg Masses ◽  
Chemotherapeutic Treatment

This study describes the close association of epibiotic microbial fouling on the eggs of Cancer magister and egg mortalities. Laboratory experiments showed that nutrient enriched sea water increased the number of measurable filaments on the egg surface and increased the number of egg mortalities. Chemotherapeutic treatment of the sea water decreased the number of filaments and mortalities. The use of antibiotics decreased the number of mortalities while the number of filaments steadily increased, suggesting that antibiotic-sensitive, nonfilamentous forms may be substantially responsible for mortalities caused by microbial fouling. Darkness and ultraviolet irradiation of the sea water had no significant effects on filaments or egg mortalities. Both filamentous fouling and egg mortalities described exponential declines with increased depths into the egg masses.

scholarly journals Horizontal distributions of Dungeness crab (Cancer magister) and red rock crab (Cancer productus) larvae in the Strait of Georgia, British Columbia

2014 ◽  
Vol 71 (9) ◽  
pp. 2564-2577 ◽  
Author(s):  
Kevin A. Sorochan ◽  
Pedro A. Quijón
Keyword(s):  
Horizontal Distribution ◽  
Spatial And Temporal Variability ◽  
Dungeness Crab ◽  
Physical Processes ◽  
Cancer Magister ◽  
Strait Of Georgia ◽  
Water Properties ◽  
Larval Stages ◽  
Cancer Productus ◽  
Rock Crab

Abstract The supply of planktonic larvae to adult populations is an important contributor to the spatial and temporal variability of benthic marine organisms. The ability to predict spatial patterns of larvae and recruits from the physical and biological processes that facilitate dispersal is required in order to advise and evaluate conservation and fisheries management decisions. In the present study, the horizontal distribution of Dungeness crab (Cancer magister) and red rock crab (Cancer productus) zoeae was described from surveys conducted in the Strait of Georgia in the spring of 2009 and 2010. Processes that may be responsible for generating spatial variability of larvae were evaluated based on (i) horizontal overlap between larvae and water properties, (ii) spatial dependence of larvae and water properties, and (iii) changes in the dispersion of stage-specific distributions. Interspecific variability between horizontal patterns of the first and second larval stages was primarily attributed to differences in the distribution of larval release locations, which appeared to be restricted to the southern and central strait for C. magister. Potential effects of physical processes on larval distributions are also discussed.

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

scholarly journals Thermal tolerance of the zoea I stage of four Neotropical crab species (Crustacea: Decapoda)

2018 ◽  
Vol 35 ◽  
pp. 1-5
Author(s):  
Adriana P. Rebolledo ◽  
Rachel Collin
Keyword(s):  
Thermal Tolerance ◽  
Elevated Temperatures ◽  
Marine Invertebrates ◽  
Negative Impact ◽  
Larval Survival ◽  
Crab Species ◽  
Marine Habitat ◽  
Mangrove Species ◽  
Larval Stages ◽  
Carry Over

. Although larval stages are often considered particularly vulnerable to stressors, for many marine invertebrates studies of thermal tolerance have focused on adults. Here we determined the upper thermal limit (LT50) of the zoea I of four Caribbean crab species (Macrocoelomatrispinosum, Aratuspisonii, Armasesricordi, and Minucarapax) and compared their thermal tolerance over time and among species. The zoea from the subtidal species M.trispinosum and tree climbing mangrove species A.pisonii had a lower thermal tolerance, 35 and 38.5 °C respectively, than did the semiterrestrial A.ricordi and M.rapax. In all four species tested, the estimates of thermal tolerance depend on the duration of exposure to elevated temperatures. Longer exposures to thermal stress produce lower estimates of LT50, which decreased by ~1 °C from a two- to a six-hour exposure. Crab embryos develop on the abdomen of the mother until the larvae are ready to hatch. Therefore, the thermal tolerances of the embryos which need to coincide with the environmental conditions experienced by the adult stage, may carry over into the early zoea stage. Our results suggest that semiterrestrial species, in which embryos may need to withstand higher temperatures than embryos of subtidal species also produce larvae with higher thermal tolerances. Over the short term, the larvae of these tropical crab species can withstand significantly higher temperatures than those experienced in their marine habitat. Longer term rearing studies are necessary to determine the temperature at which chronic exposure has a negative impact on embryonic and larval survival.

The Effects of External Salinity on the Drinking Rates of the Larvae of Herring, Plaice and Cod

1988 ◽  
Vol 138 (1) ◽  
pp. 1-15 ◽  
Author(s):  
P. TYTLER ◽  
J. H. BLAXTER
Keyword(s):  
Time Course ◽  
Gadus Morhua ◽  
Sea Water ◽  
Fluorescein Isothiocyanate ◽  
Yolk Sac ◽  
Clupea Harengus ◽  
Larval Stages ◽  
First Feeding ◽  
Fluorescein Isothiocyanate Dextran ◽  
External Salinity

Drinking responses to salinity change in the larvae of herring (Clupea harengus L.), plaice (Pleuronectes platessa L.) and cod (Gadus morhua L.) were measured from the time course of uptake of dextran labelled with tritium, following immersion in solutions of 32‰ and 16‰ sea water. The yolk sac and first feeding larval stages of all three species drink in both salinities. Furthermore, post-yolk sac stages appear to adjust their drinking rates to compensate for different salinities in a manner similar to that of the adults. Drinking rates in 32‰ sea water are approximately double those in 16‰. Mass-related drinking rates of larvae are higher than those in adults, but the differences do not match the differences in surface area to mass ratios, suggesting that larval skin is less permeable to water than is adult gill epithelium. Water absorption is indicated by the evidence of concentration of dextran in the gut. The estimates of drinking rates from tritiated dextran uptake are supported by epifluorescence microscopical measurements of the uptake of fluorescein isothiocyanate dextran.

An Analysis of Acid-Base Disturbances in the Haemolymph Following Strenuous Activity in the Dungeness Crab, Cancer Magister

1979 ◽  
Vol 79 (1) ◽  
pp. 47-58
Author(s):  
D. G. McDONALD ◽  
B. R. McMAHON ◽  
C. M. WOOD
Keyword(s):  
Lactate Concentration ◽  
Dungeness Crab ◽  
Acid Base ◽  
Cancer Magister ◽  
Rapid Release ◽  
Strenuous Activity ◽  
Lactate Levels ◽  
Acid Base Disturbance ◽  
Base Disturbance

Enforced activity causes a marked depression of haemofymph pH in Cancer magister. Both lactate concentration and PCOCO2 of the haemolymph are elevated immediately following exercise but resting PCOCO2 is restored within 30 min whereas resting lactate levels are not restored for at least 8 h. The haemolymph acid-base disturbance is caused largely by elevated haemolymph lactate levels but a Davenport analysis based on measurements of pH and total CO2 reveals a marked discrepancy between the amount of metabolic acid buffered by the haemolymph and the lactate anion concentration. This appears due to a more rapid release of lactate from the tissues than H+ ions produced with lactate.

scholarly journals Effects of Temperature on the Survival and Larval Development of Deiratonotus Japonicus (Brachyura, Camptandriidae) as a Biological Indicator

2020 ◽  
Vol 8 (3) ◽  
pp. 213 ◽  
Author(s):  
Il-Kweun Oh ◽  
Seung-Woo Lee
Keyword(s):  
Larval Development ◽  
Brachionus Plicatilis ◽  
Survival Rates ◽  
Biological Indicator ◽  
Larval Survival ◽  
Effect Of Temperature ◽  
Larval Stages ◽  
Kanagawa Prefecture ◽  
Survival And Growth ◽  
Increasing Temperature

Deiratonotus japonicus (D. japonicus) inhabits isolated locations and upstream brackish waters from Kanagawa Prefecture to Okinawa Prefecture in Japan. This species faces the threat of extinction because of changing habitat conditions. Our previous studies have shown that its complete larval development from hatching to metamorphosis consists of five zoeal stages and one megalopal stage. In this study, the effect of temperature on the survival and growth of larval development in D. japonicus under controlled laboratory conditions of 13, 18, 23, 24, 25, and 26 °C was investigated by rearing larvae (30 PSU; 12:12 h light/dark cycle; fed a diet of Brachionus plicatilis rotundiformis and Artemia sp. nauplii). The survival rates and developmental periods were measured for each larval stage. The highest survival rates were obtained at 18–24 °C. Metamorphosis to megalopa occurred at 23–25 °C. There were rapid and synchronous developments at 25–26 °C but delayed and extended developments at 13 °C. The molting period decreased with increasing temperature. With decreasing temperature, the beginning of the development and duration of molting was prolonged. In addition, there were very low survival rates at 13 °C and 26 °C in all zoeal stages. Our results indicate that the early larval stages of D. japonicus are well adapted to 18–24 °C, the range observed in the estuarine marine environment of the Kita River during the breeding season. Optimum larval survival and growth were obtained at 23 °C. Temperature significantly affected the survival rate, developmental period, and molting of the larvae. The relationship between the cumulative periods of development from hatching through individual larval stages (y) and temperatures (T) was described as a power function (y = a × Tb).

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