Light traps as a tool to sample pelagic larvae of American lobster (Homarus americanus)

The long-range dispersal of pelagic larvae is often assumed to be the dominant force behind connectivity in the marine environment, with little consideration given to benthic movements. We analyzed data from an American lobster (Homarus americanus) tagging study (1980–1996) in the Gulf of St. Lawrence during which 37 579 adults from 14 locations were tagged and 6296 were recaptured after 1–6 years at large. The 10th percentile greatest distance moved by tagged lobsters after 1 year at large contributed to demographic connectivity between neighbouring statistical districts, fishing ports, and (in one location) management areas. Considering the incremental dispersal of lobsters after 2 versus 1 year at large, we estimated that the 10th percentile greatest benthic dispersal distances after 1, 2, and 5 years at large represented, respectively, 7%, 14%, and 35% of larval dispersal in the “downstream” direction and 75%, 111%, and 220% of larval dispersal in the “upstream” direction (similar results obtained based on mean dispersal values). We conclude that more attention should be given to benthic movements in estimating connectivity and stock structure in American lobster.

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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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