Distribution and Ecology of the White Point Sicyonia ingentis Population.

Abstract

The ridgeback prawn, Sicyonia ingentis , is a dominant member of the shelf assemblage at White Point, CA. However, despite the commercial viability of this species in other areas, very little is known about the ecology of this species. The White Point area of the Palos Verdes Peninsula is a unique location; for more than 30 years the SDLAC has operated a sewer outfall on the silty upper slope of the shelf. Thirty years ago, the area was also one of the world's largest DDT dump sites. These environmental conditions provide the opportunity to determine how pollution affects distribution and ecology.This year-long research project focuses on determining the shrimp's distribution, yearly population trends, sex ratios, spawning and recruitment cycles, and age.This data is collected by surveying the population with monthly otter trawls at varying depths and locations. Initial results indicate that the shrimp spend the summer months at 50-90 fathoms with sex ratios skewed from 50:50. The females are more abundant and larger in size.The distribution also appears to be influenced more by the location of the sewer outfall than by the depth.Hopefully this population will be compared to another population at a relatively clean site.