Plankton Sampling during the Whale Habitat and Prey Study July 10-August 4, 1996

摘要

Two large area surveys and one small area survey composed of 68 plankton samplingstations were completed in the Southern California Channel islands during the 1996 Whale Habitat and Prey Study. Euphausia pacifica, Nematocelis difficilis, and Thysanoessa spinifera were the dominant euphausiids captured during the large area surveys. Euphausia pacifica, Nyctiphanes simplex, and T. spinifera were the dominant euphausiid species captured during the small area survey. Calanoid copepods were the most common non-euphausiid taxa captured during both survey types. Euphausia pacifica was most commonly distributed adjacent to and offshore of the 200 m depth contour, and T. spinifera was most commonly distributed adjacent to and offshore of the 200 m depth contour. Length frequency data indicated the majority of euphausiids captured were adult sized except for T. spinifera individuals which were predominantly late juveniles and developing preadults. Fecal samples collected during the survey indicated E. pacifica and T. spinifera were targeted by blue, fin, and humpback whales in the study area.