Seasonal changes in feeding types of estuarine benthic invertebrates from delaware bay

Abstract

One hundred and fifty quantitative benthic invertebrate samples were collected during five consecutive seasonal cruises (May 1974 to May 1975) in a small area of southwestern Delaware Bay. The samples were divided into four site groups: 1. 1) clean, fine sand 2. 2) coarse sand 3. 3) serpulid tubes; and 4. 4) muddy sand. Each group was characterized by percentage composition of feeding type, dominance, density, and an evenness measure or scaled standard deviation (SDN). Based on earlier work in a small, relatively homogeneous area, SDN had been used to relate diversity to resource sharing in a benthic community; and so this measure was applied to a larger, more heterogeneous area. Present classifications of feeding types are inadequate for an assessment of resource sharing in mixed habitats. Significant problems in analysis emerge because of insufficient data on individual feeding habits. Similar problems were noted in research from European coastal waters. The seasonal effect of meroplankton on the structure and function of benthic assemblages was inferred from plankton samples. These samples suggested explanations for heavy recruitment of a few dominant species. Finally, the biota of the four groups was compared with other assemblages in the mid-Atlantic Bight which show some strong similarities.