Population characteristics and movements of American lobsters (Homarus americanus H. Milne-Edwards, 1837) captured in the Minas Region of the Inner Bay of Fundy, Nova Scotia

Abstract

Tidal power potential is being explored for Minas Passage, the body of water that connects Minas Basin to the Bay of Fundy (BoF). The Minas Channel ̶ Minas Basin area of the BoF supports an American lobster fishery of ~200t worth $2.0-3.0 million/year. Three studies in the region were conducted during 2008-2018 to evaluate population characteristics and movement of lobsters for future assessment of impacts from tidal power development. A total of 12,327 lobsters captured in commercial and experimental lobster traps were examined for carapace length (CL), sex, and reproductive condition. Of these, 5614 marked with exterior streamer tags during 2008 and 2017 were released for recapture information from fishers. During 2011-2013 and 2017-2018, 125 and 50 lobsters, respectfully, were marked with acoustic tags and monitored in Minas Passage and Minas Basin with acoustic receivers deployed by Acadia University, the Mi’kmaq Conservation Group, the Ocean Tracking Network, and Fundy Ocean Research Center for Energy. Carapace length of males and females ranged from 41-200 mm and 51-216 mm and mean CL varied from 87.1-121.0 mm and 88.3-115.7 mm, respectively. Male: female ratios ranged from 1.0:0.6-1.0:1.2. Mean daily movement varied from 0.33 km/d to 1.21 km/d. Females released larvae during July, egg extrusion began in October, and proportion of berried females peaked in December at 50.4%. Experimental trap catches, streamer tag returns, and acoustic detections indicated that lobsters were spread evenly over the
sampled area in summer but movement into Minas Passage occurred during autumn where the lobsters remained for winter. Movement of berried females into Minas Passage is possibly a local life history strategy that enhances development rate of attached eggs in the relatively warmer water of this region during winter (+1.0^oC). Lobsters marked with streamer tags migrated throughout the BoF and were reported from traps off Advocate and as far as Grand Manan and SW Nova Scotia (200+ km).