Habitat associations of juvenile American lobster in three nearshore areas of Newfoundland

This project was completed by the Productive Capacity group (Coastal and Freshwater Ecology Section) in the Newfoundland and Labrador Science Branch of Fisheries and Oceans Canada (DFO).

American lobster (Homarus americanus) is a commercially important decapod crustacean species along the east coast of North America, ranging from the Labrador coast south to Cape Hatteras. Juvenile lobster < 40 mm CL (carapace length) recruitment has been studied extensively in the southern portions of their range. However, investigations of settlement habitat association and recruitment of juvenile lobster in the northern extremes along the Newfoundland coast have been largely unsuccessful. We investigated juvenile lobster density, habitat, and depth associations in three areas of Newfoundland, using scuba – Port Saunders area, 8 dives conducted 28 September - 2 October 2017, and Burin Peninsula 10 dives (7 Placentia Bay, 3 Fortune Bay) conducted 30 September - 4 October 2018 over a total seabed area of 9,138 m2, within 200 meters of shore. Port Saunders and Fortune Bay had relatively higher lobster density (0.09 and 0.40 m-2, respectively); >65% were juveniles, in contrast to Placentia Bay where lobster densities of all size groups were low (mean 0.01 m-2) and no juvenile lobsters were observed at all. Where observed all juvenile lobster were significantly associated with shallow (<6 m) habitat and showed no overlap with distribution of adults (>82.5 mm CL) which we observed at depths 6 to 17 m. Our sites were dominated by varying mixes of cobble and pebble (77%); rock/bedrock (12%) and mud/sand/small pebble (11%) substrates interspersed with overlying kelp (32%) and eelgrass (11%) vegetation. We observed no significant associations with substrate or vegetation.

This record contains the geographic locations of the 7 Placentia Bay sites surveyed, and information on the timing and type of data collected at each site, which was one component supported by Coastal Environmental Baseline Program of a larger collaborative project.