Spatial scaling of habitat distributions in the American lobster

American lobster (Homarus americanus) preferences for nearshore cobble habitats are well known yet little is understood about the effects of spatial scaling of habitat patches on lobster distribution patterns. We studied patterns of lobster distributions for a range of spatial scales in two regions in Atlantic Canada immediately following heavy fisheries exploitation. In the southern Gulf of St. Lawrence habitat patches were extremely complex and fragmented at large spatial scales yet the flat cobble and bedrock substrates yielded relatively little crevice space at the scale of individual lobster shelters. Densities in the nearshore were low and heavily skewed towards juveniles. Exceptions were in relic stream beds which were small in area but contained the most productive habitats. In contrast, at our Gulf of Maine sites patch sizes were very large and fragmentation was low. Small scale structural complexity was high and supported greater densities of all sizes classes of lobsters. In addition, adult lobsters were also distributed on soft sediments and on large patches of horse mussels far from shelter patches. Our study demonstrates the value of analysing distribution patterns at multiple spatial scales.