Herbivores and detritivores in Puget Sound

Many consumer organisms in Puget Sound are both herbivores and detritivores. Zooplankton and benthic invertebrates that are scavengers, herbivores, or detritivores are considered jointly in this article. Some of these organisms can be predatory as well. Hundreds of invertebrates and fish species have a planktonic larval stage that eats plants and occupies the nearshore and offshore pelagic waters of Puget Sound.

Dungeness crab. Photo: Leo Shaw, The Seattle Aquarium.

Life cycles

While many species of invertebrates (e.g. copepods) complete their entire life cycles in the water column, many cnidarians, arthropods, mollusks, echinoderms, annelids, tunicates, and fish species are present in the plankton for only a portion of their life cycle. Most filter-feeding pelagic zooplankton, as well as many suspension-feeders, are dependent on phytoplankton for food. They are thus an important step in the pelagic part of the food web, transforming the organic matter derived from primary production into food for invertebrates, fish, birds, and mammals. The distribution and abundance of zooplankton are probably correlated with changes in distribution of phytoplankton (Strickland 1983), but quantitative studies of the zooplankton assemblage in the Puget Sound region are rare and quite limited in scope.

Benthic invertebrates

The benthic habitats of Puget Sound are home to thousands of species of herbivorous/detritivorous invertebrates. These species include those that live in the bottom (infauna) and on the surface of the bottom (epifauna) and that may be motile or sessile (Kozloff 1983). The adult stages of a number of benthic species are economically important and include native species such as pandalid shrimp (Pandalus spp.), Dungeness crab (Cancer magister), geoduck clam (Panopea generosa), and butter clam (Saxidomus giganteus), as well as non-native species such as Japanese littleneck clam (Tapes philippinarum) and Pacific oyster (Crassostrea gigas). These benthic invertebrates also use a variety of feeding methods, including filter or suspension feeding (mussels, clams, scallops, oysters, worms, and barnacles) and grazing (sea urchins, snails, limpets, and chitons). Detritivorous invertebrates include sea cucumbers, crabs, amphipods, and isopods. These taxa are preyed on by other invertebrate, fish, mammal, and bird species as adults or as eggs and larva when vast amounts are released during reproduction.

About the Author: 
The development of the Sound Science document has been a collaborative process among scientists from a variety of disciplines and institutions throughout Puget Sound. The content reflects the wealth of knowledge in existing plans, research projects and personal expertise. The open dialogue and vigorous discussion about the interactions between components of the ecosystem, key threats to the system and critical science needs is almost as significant as the findings themselves. This document is the product of over 30 authors and almost 100 reviewers from federal, tribal, state, local, non-governmental, and academic institutions across the Puget Sound region. In total, hundreds of natural and social scientists have contributed either as co-authors, through extensive reviews, or by participating in workshops to debate and improve the information. We believe that the resulting content of the document thus reflects the collective views of the broad community of natural and social scientists familiar with Puget Sound. Key contributing agencies: King County Department of Natural Resources and Parks, National Oceanic and Atmospheric Administration (NOAA), Northwest Indian Fisheries Commission, People for Puget Sound, Puget Sound Action Team, The Nature Conservancy, US Environmental Protection Agency, US Geological Survey, University of Washington, Washington State Department of Ecology, Washington Department of Fish and Wildlife, Washington State Department of Health, Washington State Department of Natural Resources.

About this article

Article Type:
Overviews
Author:
Sound Science Contributors; NOAA Fisheries, Northwest Fisheries Science Center
External Publication Source:
Sound Science
Originally Published:
January 2007
Posted in EoPS:
02/16/2012
Topic Editor:
Encyclopedia of Puget Sound
Tags:
Species and food webs, Invertebrates