Investigations Into Temporal Patterns in Distribution, Abundance and Habitat Relationships Within Seabird Communities of the Eastern Tropical Pacific

摘要

Of the approximately 100 seabird species recorded in the eastern tropical Pacific (ETP), nine were selected as indicators of the ecosystem, including the most abundant and widespread species in the ETP, and a diverse array of taxa and residence patterns, trophic levels, and foraging guilds. The latter is particularly relevant because four of the nine species are dependent upon the same tuna/dolphin assemblage as that targeted by the purse seine fishery, for successful foraging opportunities. These four species are referred to as tuna-dependent whereas the other five seabird species feed in other ways and thus are tuna-independent. Seabird data were collected during three years each of the Monitoring of Porpoise Stocks (MOPS) and Stenella Abundance Research (STAR) Projects (1988 - 1990 and 1998 - 2000, respectively) using 300 m strip transect methods. Three measures of temporal change were investigated: distribution, abundance, and habitat association patterns. Annual distribution patterns illustrate two features.