Marine, intertidal, mud, protected, eulittoral

In calm bays and inlets where there is little to no wave or current energy, fine sediments settle and form mudflats, ranging from relatively firm (with some sand) to very soft silt.  Often such areas have seasonal freshwater inflow from streams, but salinities are not regularly below 30 ppt. Such habitats support a rich infauna and are used extensively by birds as foraging areas; these habitats and their estuarine counterparts support the highest densities (seasonally) of marine birds in the region. These include great blue herons, gulls, terns, turnstones, dunlin, sandpipers, grebes, and ducks. Areas with eelgrass are used by black brant and wigeon, and to a lesser extent by Canada geese, pintails, and greater scaup.  Seals sometimes haul out on undisturbed mudflats.  Drift algae and seagrass may accumulate.

Habitat attributes

Class ID: 
Class name: 
Marine, intertidal, mud, protected, eulittoral
3.0 km (in WA)
Primary substrate: 
Secondary substrate: 
Tertiary substrate: 
Substrate stability: 
Substrate key details: 
No stable surface features; sediments mostly fine
Wave exposure: 
Protected, Very protected
Blue book classes: 
Marine intertidal mud: Protected
Map/survey site examples: 
Westcott Bay, Garrison Bay, Jamestown; Mud Bay (Lopez)
Fish sampling sites: 
Diagnostic species: 
  • Zostera marina
  • Macoma nasuta
  • Upogebia pugettensis
  • Abarenicola pacifica
  • Haminoea
  • Leptocottus armatus
  • Lumpenus sagitta
  • Parophrys vetulus
  • Cymatogaster aggregata
VEC common associates: 
Cancer spp.
Species notes: