Deep Benthic Environment. The deep benthic areas of the Port are those on the bottom below approximately 50 meters to over 200m. Sedimentation in the deep basin is high during the summer with greater sediment accumulation at the eastern end. Consequently, the bottom consists of mostly fine, loosely packed, glacially derived sediments. Sediment slumping occurs along the basin walls, especially in the eastern end of the Port. Polychaetous worms and small clams are the predominant invertebrates living within the sediments. Crangonid and pandalid shrimps, Xxxxxx and Dungeness crabs, and bottom fishes were the dominant organisms living on the sediment surface in a study conducted by Xxxxx and Xxxx (1977). Shrimp, crabs, and bottom fishes feed on the living or dead organic matter found within or on the sediments. The abundance and biomass of invertebrates living in or on sediments tends to be low (100 to 650 individuals/m2 and biomass 0.3 to 1.2 gC/m2) (Xxxxx and Xxxxxx, 1988). These invertebrates support low numbers of feeding shrimp, crabs, and bottom fishes compared to other deep benthic environments in PWS and the adjacent Gulf of Alaska shelf (Xxxxx and Xxxxxx, 1987). Examples of receptors and their probable activity in this habitat are listed in Table 5-11. Table 5-11. Receptors linked to the deep benthic habitat, either through residence in or use of the habitat. Deep Benthic Habitat Receptor Specific Examples Habitat Use Invertebrates Polychaete worms Xxxxxx in sediments; mostly deposit feeding; some suspension feeders, predators, or scavengers; growth and reproduction Clams Xxxxxx in sediments; suspension feeding, surface and sub-surface deposit feeding; growth and reproduction Crabs Feed on invertebrates; growth and reproduction Shrimp Feed on detritus and small organisms; growth and reproduction Fishes Benthic fishes Feed on invertebrates or other fishes; growth and reproduction
