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Distribution of nekton species and abundance within and among four Oregon estuaries
Citation:
Woodworth, C., I. Heller, D. R. YOUNG, AND T. H. DEWITT. Distribution of nekton species and abundance within and among four Oregon estuaries. Presented at Coastal and Estuarine Researach Federation (CERF) Biennial Meeting, Daytona Beach, FL, November 06 - 10, 2011.
Impact/Purpose:
Crabs, shrimps and fishes provide valued ecosystem goods and services to communities of the Pacific Northwest, including species that are fished for food and recreation and those that serve as prey for fished species.
Description:
Crabs, shrimps and fishes provide valued ecosystem goods and services to communities of the Pacific Northwest, including species that are fished for food and recreation and those that serve as prey for fished species. In the face of increasing use of these services and potential threats to their productivity (i.e., climate change, water pollution), it is essential to understand the distribution of nekton on both local and regional scales so that their productivity may be better estimated. Low-tide sampling surveys were conducted at >20 stations in intertidal channels in each of four Oregon estuaries (Tillamook, Yaquina, Alsea, and Coos) using a 3m-wide plumb-staff beam trawl; depth, temperature, and salinity were also measured at each station. Species’ densities were calculated from abundance and area-swept; lengths of abundant species were measured. Preliminary analyses reveal that species richness followed a log-normal distribution, with only two or three dominant species at each site, and that biodiversity decreased with distance from the estuary mouth. Dungeness crabs (Cancer magister) had the highest density in Coos Bay, whereas sand shrimps (Crangon spp.) had the highest densities in Yaquina, Alsea, and Tillamook estuaries across all samples combined. English sole (Parophrys vetulus) was the most abundant fish in all four estuaries. Biodiversity and population densities of C. magister and P. vetulus were weakly positively correlated with salinity and temperature, while the population distributions of Pacific staghorn sculpin (Leptocottus armatus) and sand shrimps were more evenly dispersed across salinity and temperature gradients. Future analyses will examine whether intertidal habitat type and area are better predictors of nekton diversity, distribution, abundance, and biomass.