SPATIAL AND TEMPORAL CHANGES IN THE GROUNDFISH ASSEMBLAGES ON THE NORTHEAST NEWFOUNDLAND LABRADOR SHELF, NORTH-WEST ATLANTIC, 1978-1991

From 1978 to 1991, biomass and abundance have declined in members of t he marine fish community on the Newfoundland-Labrador Shelf. This decl ine was common to all commercial groundfish and to many noncommercial ones as well. Since about 1985, the biomass decline has been accompani ed by major shifts in the geographic distribution of almost every spec ies. Some species disappeared from inshore, others disappeared from th e north, and others did both. Some species appear to have had major sh ifts in abundance (north to south or inshore to offshore) whereas othe r species exhibited a biomass decline in one area but maintained a rat her uniform level in others. Multivariate analysis of groundfish surve y data identified four groundfish assemblage areas on the shelf, i.e. areas characterized by a homogeneous faunal composition. Distribution patterns of the assemblages remained relatively stable from 1978 until 1987, but have entered a period of dramatic change since then. Change s in the distribution patterns of individual species anticipated chang es at the community level. Intense exploitation of groundfish is the m ost likely explanation for the decline of fish biomass on the Newfound land-Labrador Shelf. The shifts in distribution observed, however, sug gest that broad scale environmental effects may also be at work.