Effect of Solitude on Time Between Fourth and Fifth Larval Molts in the American Lobster (Homarus americanus)

J. Stanley Cobb

doi:10.1139/f70-185

Effect of Solitude on Time Between Fourth and Fifth Larval Molts in the American Lobster (Homarus americanus)

Journal of the Fisheries Research Board of Canada ◽

10.1139/f70-185 ◽

1970 ◽

Vol 27 (9) ◽

pp. 1653-1655 ◽

Cited By ~ 15

Author(s):

J. Stanley Cobb

Keyword(s):

Homarus Americanus ◽

American Lobster ◽

Fourth Stage

Larvae held individually in containers spent an average of 12 days in the fourth stage. When held two larvae per container, one molted after an average of 12 days, the second after an average of 16 days. Duration of the fourth stage was not affected by gravel, shelter or bare bottom conditions, or illumination varying from <1 lux to 310 lux.

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Effects of Crude Oil on American Lobster (Homarus americanus) Larvae in the Laboratory

Journal of the Fisheries Research Board of Canada ◽

10.1139/f76-200 ◽

1976 ◽

Vol 33 (7) ◽

pp. 1604-1614 ◽

Cited By ~ 58

Author(s):

Peter G. Wells ◽

John B. Sprague

Keyword(s):

Crude Oil ◽

Larval Development ◽

Food Consumption ◽

Ultrasonic Vibration ◽

Homarus Americanus ◽

American Lobster ◽

Fourth Stage ◽

Dispersed Oil ◽

Reference Toxicant

Four-day LC50s for Venezuelan Tia Juana crude oil were 0.86 mg/liter for first-stage larvae of the American lobster (Homarus americanus) and 4.9 mg/liter for third- and fourth-stage larvae. The 30-day LC50 was 0.14 mg/liter for larvae starting the test in their first stage. The threshold for retardation of larval development was about the same as the 30-day LC50. Decreased food consumption was demonstrated at 0.19 mg/liter. More "intermediate" larvae developed in oil exposures but no threshold was estimated. The ratio of "safe" to acutely lethal concentrations was about 0.03.Oil concentrations decreased during exposures; stated values could be multiplied by 0.59 to arrive at conventional average exposures. Stirring and ultrasonic vibration for 30 min dispersed averages of 7.4 and 18% of added oil. This and other techniques apparently dispersed similar components since toxicities were the same when based on measured concentrations. Aged dispersions were also equally toxic on a measured basis. Particles larger than 1.2 μm made up 84–96% of the dispersed oil and were about one-third as toxic as smaller particles and dissolved oil. For the reference toxicant DSS, the 4-day LC50 was 0.72 mg/liter for first-stage larvae indicating that lobster larvae are sensitive. Post-larval lobsters dug significantly more burrows when the substrate contained oil but did not avoid oiled substrate nor was growth or survival affected for substrates containing up to 1740 mg/liter of oil.

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Behavior and Distribution of Larval and Early Jevenile Homarus americanus

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f83-252 ◽

1983 ◽

Vol 40 (12) ◽

pp. 2184-2188 ◽

Cited By ~ 28

Author(s):

J. S. Cobb ◽

T. Gulbransen ◽

B. F. Phillips ◽

D. Wang ◽

M. Syslo

Keyword(s):

Stage Iv ◽

Homarus Americanus ◽

American Lobster ◽

Substrate Selection ◽

Fourth Stage ◽

Shallow Sea ◽

Behavioral Observations

Field behavioral observations and plankton tows show that American lobster (Homarus americanus) larvae are concentrated in downwellings characteristic of shallow sea fronts. Stage IV lobsters swimming at the surface avoided floating weeds and sticks. Seventy percent of laboratory-reared fourth stage lobsters swam near the surface for more than a minute when released but only 25% of fifth stage lobsters did so. When early fourth stage lobsters encountered bottom, they did not remain long in one place, but late fourth and early fifth stage lobsters began to burrow. Late fourth and early fifth stage lobsters were less likely to return to the surface when they reached the bottom. If the bottom was unsuitable (featureless sand), the lobsters resumed swimming. These behaviors appear to be an appropriate mechanism for substrate selection during settlement.

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Growth of juvenile American lobster Homarus americanus in a changing environment

Marine Ecology Progress Series ◽

10.3354/meps11854 ◽

2016 ◽

Vol 557 ◽

pp. 177-187 ◽

Cited By ~ 8

Author(s):

MD McMahan ◽

DF Cowan ◽

Y Chen ◽

GD Sherwood ◽

JH Grabowski

Keyword(s):

Homarus Americanus ◽

American Lobster ◽

Changing Environment

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Predicting bycatch hotspots based on suitable habitat derived from fishery-independent data

Marine Ecology Progress Series ◽

10.3354/meps13302 ◽

2020 ◽

Vol 641 ◽

pp. 159-175

Author(s):

J Runnebaum ◽

KR Tanaka ◽

L Guan ◽

J Cao ◽

L O’Brien ◽

...

Keyword(s):

Habitat Suitability ◽

Mixed Model ◽

Linear Mixed Model ◽

Gulf Of Maine ◽

Homarus Americanus ◽

Management Tool ◽

American Lobster ◽

Suitable Habitat ◽

Climate Conditions ◽

Suitability Index

Bycatch remains a global problem in managing sustainable fisheries. A critical aspect of management is understanding the timing and spatial extent of bycatch. Fisheries management often relies on observed bycatch data, which are not always available due to a lack of reporting or observer coverage. Alternatively, analyzing the overlap in suitable habitat for the target and non-target species can provide a spatial management tool to understand where bycatch interactions are likely to occur. Potential bycatch hotspots based on suitable habitat were predicted for cusk Brosme brosme incidentally caught in the Gulf of Maine American lobster Homarus americanus fishery. Data from multiple fisheries-independent surveys were combined in a delta-generalized linear mixed model to generate spatially explicit density estimates for use in an independent habitat suitability index. The habitat suitability indices for American lobster and cusk were then compared to predict potential bycatch hotspot locations. Suitable habitat for American lobster has increased between 1980 and 2013 while suitable habitat for cusk decreased throughout most of the Gulf of Maine, except for Georges Basin and the Great South Channel. The proportion of overlap in suitable habitat varied interannually but decreased slightly in the spring and remained relatively stable in the fall over the time series. As Gulf of Maine temperatures continue to increase, the interactions between American lobster and cusk are predicted to decline as cusk habitat continues to constrict. This framework can contribute to fisheries managers’ understanding of changes in habitat overlap as climate conditions continue to change and alter where bycatch interactions could occur.

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