Linking fish and shags population trends

This document analyses and relates long term information on population trends of inshore demersal fish and Antarctic shags of the South Shetland Islands. The analysis is complemented with comparable information on diet, foraging patterns and breeding output of shags from the Danco Coast, western Antarctic Peninsula, an area that has remained out of the influence of the commercial fishery. Instead of climate change processes, indicated as responsible for the diminution of other bird populations, the most reliable cause of the declining trend observed in shag colonies at the South Shetland Islands is the concomitant decrease in the abundance of two of their main preys, the nototheniids Notothenia rossii and Gobionotothen gibberifrons, owed to the intensive industrial fishing in the area in the late 1970s.