Invertebrates of the Salish Sea

Sponsored by the Rosario Beach Marine Laboratory, Fidalgo Island, Anacortes, WA; a campus of Walla Walla University

Anthopleura elegantissima anemone dividing Calliostoma annulatum Ringed top snail Cancer magister Dungeness crab Henricia leviuscula Blood star

This page serves as an entrance to a fascinating look at many of the marine invertebrates found in and near the Salish Sea, especially Puget Sound and the Straits of Juan de Fuca, Washington.  Each species has a special page with its description, photos, and notes about its natural history plus observations we have made of the species.  Most of the photos were taken of live animals, either in the field or in the lab on animals that were then returned to the field.  I am a scientist and teacher, not a professional taxonomist and I have been known to mis-identify a species on occasion, so if you see something that needs to be corrected please contact me.  My sincere thanks to the experts on various groups who have given me advice and helped with identification.  You can also check out my main web page at

If you know or think you know the group or name of your species you may quickly navigate directly to it by using the Alphabetic or Systematic indices; otherwise you may use the dichotomous keys to find out what it is.  Wherever possible, the keys are supplemented with definitions to terms and with pictures of relevant species and the parts being compared.  You can also go directly to the glossary from nearly any page to look up other terms. Cautionary note: Systematic classification of these species is continually changing. I try to keep up with these changes, but this site should not be considered authoritative for the latest systematic (taxonomic) classification.


Alphabetic List of Species and Groups


Illustrated Glossary

Systematic Index

(Organized in Systematic order, alphabetically under phyla)

Annotated Bibliography

Key to Species--Starting with Recognizable Group 

(Starts with Phylum, Class, or other recognizable group, which are listed alphabetically by phylum)

Other Web Resources

Key to Groups of Invertebrates 

(Start here if you don't know what kind of animal it is or what group an animal is in)

Content partner to the Encyclopedia of Life

What is the Salish Sea and where is the 
Rosario Beach Marine Laboratory located in it?

Contributors to this Project

Introduced Species and Species of Concern in the Salish Sea
(Covers only marine invertebrates)

Send me Feedback

(comments, corrections, observations, permission to use photos)
Instructions on how to use a dichotomous key

I've been interested in this for a long time! (photos)

The key currently contains more than 450 species in 17 Phyla, 80 Orders, and 200 Families.

Keys to Species, Starting By Recognizable Group (Arranged Alphabetically by Phylum):

In the list below, just click on the taxonomic level that you wish to jump directly to.  Phyla are listed in alphabetic order.
Phylum Annelida:  Segmented worms
    Class Polychaeta

Phylum Arthropoda:  Crustaceans and Chelicerates
    Subphylum Chelicerata
        Class Pycnogonida:  Pycnogonids, sea spiders
    Subphylum Crustacea
        Class Maxillopoda
        Infraclass Cirripedia:  Barnacles
        Class Malacostraca
            Superorder Eucarida
                Order Decapoda
        Infraorder Thalassinidea:  Mud shrimp and ghost shrimp
                    Infraorder Anomura: Hermit crabs and other crablike species
        Infraorder Brachyura: True crabs
        Natantia--shrimp (Caridea) and prawns (Dendrobranchiata, Penaeida)
        Infraorder Caridea:  Shrimp
        Infraorder Penaeidea:  Prawns
            Superorder Peracarida
        Order Amphipoda:  Amphipods
        Order Isopoda: Isopods
        Order Lophogastrida:  Lophogastrids--Deep-sea shrimplike species such as Gnathophausia
        Order Mysida: Mysids

Phylum Brachiopoda:  Lampshells

Phylum Bryozoa

Phylum Chordata
    Subphylum Urochordata:  Tunicates, salps, doliolids, larvaceans
        Class Ascidiacea:  Tunicates, sea squirts

Phylum Cnidaria:
    Class Anthozoa:  Anemones, corals, sea pens
    Class Hydrozoa:  Hydroids, siphonophores, hydrozoan jellyfish
        Hydroid polyps (Order Hydroida have a well-developed polyp--most colonial hydroids are here)
        Orders Chondrophora/ Siphonophora (Siphonophores--pelagic, floating or midwater colonies with float or swimming bells)
        (sub)order Stylasterina (fire corals and their relatives)
    Class Scyphozoa:  True jellyfish
        Order Semaestomae:  Pelagic jellyfish
        Order Stauromedusae:  Attached jellyfish

Phylum Ctenophora:  Comb jellies

Phylum Echinodermata
    Class Asteroidea:  Sea stars
    Class Crinoidea:  Sea lilies and feather stars
    Class Echinoidea:  Urchins and sand dollars
    Class Holothuroidea:  Sea cucumbers
    Class Ophiuroidea:  Brittle stars, basket stars

Phylum Echiura: Echiuroid worms, spoonworms

Phylum Entoprocta:  Entoprocts

Phylum Hemichordata:  Hemichordates
  Class Enteropneusta:  Acorn worms

 Phylum Mollusca:
    Class Bivalvia:  Bivalves:  Clams, mussels, scallops
    Class Cephalopoda:  Octopus and squid
    Class Gastropoda:  Snails and nudibranchs
        Subclass Prosobranchia:  Most marine snails with shells
        Subclass Opisthobranchia:  Nudibranchs, etc.
    Class Polyplacophora:  Chitons
    Class Scaphopoda:  Tusk shells

Phylum Nemertea:  Ribbon or proboscis worms

Phylum Platyhelminthes:  Flatworms
    Class Turbellaria:  Freeliving flatworms

Phylum Porifera:  Sponges
    Class Demospongiae (Most of our common sponges are here)

Phylum Sipuncula: Peanut Worms


How to Use a Dichotomous Key:

  A Dichotomous key is a simple pathway to find specific information, based on a simple principle.  Choices in the key are numbered consecutively.  Each choice gives you only two options about your species, and you must decide which of the two options matches your species.  For example, choice 1a may say the species is spherical while choice 1b says the species is not spherical.  If your species is shaped like a cube, you would choose choice 1b.  At the right of each choice is a number to jump to next if that choice is correct.  For example, if choice 1b had a "7" beside it, that would mean to go next to choice 7 if choice 1b is correct.  You continue this process until you arrive at the correct species.

This key has some real advantages over a normal printed key.  First, it is web-based, and each choice is a link.  That means you can quickly travel through the key, and even back up (by using your browser's back button) easily.  Just click on the number after the correct choice and you will be taken to the next choice.  It also has many definitions and illustrations throughout, so that you can easily see what terms mean or see special structures that are described.

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What is the Salish Sea and where is Rosario Beach Marine Laboratory located in it?

The Salish Sea is the inland sea along the border between northern Washington and southern British Columbia.  It includes all the waters between or behind the Olympic Peninsula and Vancouver Island, including the Straits of Georgia and Juan de Fuca, Desolation Sound, Haro and Rosario Straits, Puget Sound, and Hood Canal.  The Salish Sea acts as an estuary due to the inflow of the Fraser River and many smaller rivers.  Cities bordering the Salish Sea include Seattle, Tacoma, Olympia, Everett, and Bellingham, Washington and Vancouver and Victoria, British Columbia.  Island groups within the sea include the northern and southern Gulf Islands and the San Juan Islands.  For more information on the Salish Sea and its ecology, for an account of how the name came to be (given by Bert Webber, who originally proposed the name), or for a geographic map of the Salish Sea or check out the SeaDocs web site.

Rosario Beach Marine Laboratory, a campus of Walla Walla University, has a central location in the Salish Sea.  The laboratory is on Fidalgo Island, one of the San Juan Islands about halfway between Seattle, WA and Vancouver, BC.  The laboratory borders Rosario Strait.  Admiralty Inlet, Puget Sound, and Hood Canal are to the south, the Strait of Juan de Fuca, San Juan Islands, and Haro Strait are to the west, and the Strait of Georgia is to the northwest.
The station is dedicated to undergraduate and graduate studies in biology, especially of marine species and the marine environment.

Rosario Beach Marine Laboratory coordinates:
     48 degrees 25 minutes 9 seconds North
     122 degrees 39 minutes 49 seconds West

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Page created by Dave Cowles, 6-2002
Edited by: Anna Dyer, 08-2002
Edited by:  Melissa McFadden, 08-2002
Edited by:  Dave Cowles, 2002-present

Salish Sea Invertebrates web site provided courtesy of Walla Walla University