Research Technical Report
Marine Bird and Mammal Distribution and Abundance in Monterey Bay, During 1996
Harvey, J.T. and S.R. Benson (1997)
Moss Landing Marine Laboratories Technical Publication 97-02, 80pp.
INTRODUCTION
In 1996, Moss Landing Marine Laboratories (MLML), and the University of California at Santa Cruz (UCSC), conducted ship-board surveys to examine marine mammal and seabird habitats in Monterey Bay, California by determining the spatial distribution patterns of their prey and associated physical oceanographic factors. This paper presents the preliminary results of five surveys of marine mammals and seabirds completed between 13 August and 25 November 1996.
The study was motivated by the need to understand the relationships between abiotic and biotic factors (e.g. bathymetry, thermal structure, and prey distribution) and marine mammal and seabird distribution and abundance. In 1998, the Monterey Bay National Marine Sanctuary was created in recognition of the biological importance of this region to marine life. Surveys targeting individual marine mammal species and seabirds have been conducted periodically in Monterey Bay to document distribution and abundance of these marine predators (Center for Marine Studies 1983; Barlow 1987; Kruse 1989; Croll 1989; Schoenherr 1991; Black 1994). Few of these surveys, however, have been comprehensive habitat studies, in which the distribution of marine mammals and seabirds was investigated simultaneously with oceanographic conditions or prey fields.
SURVEY OBJECTIVES
The primary objective of the surveys was to investigate the relationships between oceanographic conditions, prey availability, and the distribution and relative abundance of marine mammals and seabirds in Monterey Bay. The specific objectives were to:
- collect data on distribution, relative density, size, and species composition of marine mammal and seabird aggregations within Monterey Bay;
- collect physical oceanographic and biological data regarding the habitats of marine mammals and seabirds to better understand the process affecting their distribution.