RHINOCEROS AUKLET (CERORHINCA-MONOCERATA) NESTLING DIET MAY GAUGE PACIFIC SAND LANCE (AMMODYTES-HEXAPTERUS) RECRUITMENT

We studied (1984-86) the diet of rhinoceros auklet (Cerorhinca monocer ata) nestlings at three colonies on the British Columbia coast (Lucy I slands, Pine Island, and Triangle Island), On the Lucy Islands, Pacifi c sand lance (Ammodytes hexapterus) dominated nestling food loads in a ll years. In 1985, 0+ sand lance dominated the nestling diet on all co lonies. Concurrent measures of nestling growth rate, independent index es of ocean production, and the proportion of sand lance in groundfish stomach samples were also highest in 1985. This suggests a linkage be tween ocean production, 0+ sand lance abundance, and events on seabird colonies over a broad geographic range. We emphasize the importance o f sand lance to temperate seabirds and contrast British Columbia with areas where sand lance are commercially exploited. Rhinoceros auklet n estling diet, growth, and other data collected on colonies suggest tha t long-term monitoring on seabird colonies can contribute timely and i nexpensive information on the recruitment of sand lance stocks in Cana dian waters.