Marine, intertidal, mixed fine, semi-protected, eulittoral

This habitat type (or its estuarine equivalent) occurs in most bays and harbors in the Pacific Northwest. Protection from waves allows finer sediments to accumulate, and the substratum is relatively stable.  The beaches tend to be accretional.  The mixed-fine sediments include sand and mud with patches of gravel (especially in the higher intertidal).  Few marine (but many estuarine) sites in this category have been surveyed.  Species are generally a mix of those found in sand and in mud habitats.  Birds and fish using these areas are described under the counterpart Estuarine habitat.  Drift algae and seagrass may be abundant.

Habitat attributes

Class ID: 
31
Class name: 
Marine, intertidal, mixed fine, semi-protected, eulittoral
Length: 
9.0 km (in WA)
Primary substrate: 
Sand
Secondary substrate: 
Gravel
Tertiary substrate: 
Mud
Substrate stability: 
Mobile
Substrate key details: 
Pebble, sand, mud (few stable surface features)
Wave exposure: 
Semi-protected
Blue book classes: 
Marine intertidal mixed-fines: Semi-protected sites only
Map/survey site examples: 
Outer Westcott Bay, other sites in the San Juans
Fish sampling sites: 
Beach Seine: Alexander's Beach
Diagnostic species: 
  • Zostera marina
  • Zostera japonica
  • Clinocardium nuttallii
  • Parophrys vetulus
  • Leptocottus armatus
VEC common associates: 
Cancer spp.
Tresus capax
Species notes: