The impact of the commercial lobster fishery on seabirds at the tristan da Cunha Islands, South Atlantic Ocean

Abstract

Observations were made on the effect of the commercial rock-lobster Jasus tristani fishery on seabird populations at the Tristan da Cunha Islands, central South Atlantic Ocean. The most serious impact of the fishery is the large number of seabirds killed when dazzled by the ships' lights at night. These night-strikes affect thousands of individuals of eight or more species annually. Recommendations are made to reduce this largely avoidable mortality. The killing of rockhopper penguins Eudyptes chrysocome for baiting lobster traps has ceased. Indirect effects on seabird prey populations resulting from rock-lobster exploitation are likely to be negligible, because there are no inshore-feeding birds that feed extensively on benthic organisms. Dietary supplementation also is unimportant because few seabirds scavenge from the fishery relative to the large breeding populations occurring at the islands. Dumping of refuse and broken gear should be discontinued; it entangles marine birds and mammals, and is aesthetically unacceptable. Continuous vigilance is essential to keep the ships rodent-free, because their accidental introduction to the uninhabited islands poses the greatest threat to the island faunas.