PREY HARVESTS OF SEABIRDS REFLECT PELAGIC FISH AND SQUID ABUNDANCE ONMULTIPLE SPATIAL AND TEMPORAL SCALES

Many studies have demonstrated relationships between seabird prey harv ests and fisheries catches. These correlations have for the most part been found at scales from 10s to 100s of kilometers within foraging ra nges around seabird breeding colonies. In the present study, we invest igated associations between the prey harvests of northern gannets Sula bassana at a large breeding colony off the northeast coast of Newfoun dland and the catches of the inshore Newfoundland fishery at different spatial scales and time intervals. Significant correlations occurred between the seabirds' and the humans' catches of mackerel Scomber scom brus and short-finned squid Illex illecebrosus from 1977 through 1992. The relationships for squid were stronger over larger geographic area s than were those for mackerel. The associations for both squid and ma ckerel reflected abundance/availability around the colony, at a larger scale near the gannets' maximum foraging range (e.g. similar to 200 k m), and for the entire Newfoundland region (1000s of kilometers). Thes e correlations were significant at August vs August and August vs annu al time intervals. The gannets' landings of squid were also associated with fishery-independent, research survey indices of squid abundance over thousands of kilometers. The robustness of these relationships in dicates that levels of pelagic prey harvest by seabirds can provide re liable indices of prey abundance within and outside reproductive seaso ns and foraging ranges around breeding colonies. Similar relationships are predicted between seabird and human fisheries that are directed a t migratory 'warm-water' pelagic prey that move into cold and high lat itude oceanographic regions.