Deception Pass State Park 

Skagit & Island Counties, WA

Site Description:       

Deception Pass State Park falls within two counties. Rosario Beach, in Skagit County, is on the north side of Deception Pass.  It is the north side of the point of land at the northwest edge of Bowman Bay and is adjacent to the Rosario Beach Marine Laboratory. This is a rocky point of land full of tide pools but the point is now off-limits.
North and West Beaches, in Island County, are on the south side of Deception Pass.  North Beach faces Deception Pass itself.  West Beach faces the Strait of Juan de Fuca.  The beaches here are sand and pebbles and are divided by  a rocky outcropping.  

Google Map

                           on North Beach, facing the Pass               

Species List:

     Following is a list of mollusk species observed at this location by members and associates of the club.  This is by no means a complete list of the species which may occur at this site.  Revisions and additions to the data are made as we acquire new information.   When a site contains more than one very distinctive type of habitat or if multiple sites were included in a single location, then a species list for each is included.
    We indicate frequency of occurrence based on our observations.  This is an indicator of how likely it is that you may be able to find this species yourself and is not a formal population survey.  

     Frequency Code:  (Based on the assumption that you are looking in the appropriate location where the species
                                          likes to live - on rocks, in sand, etc.  Some populations fluctuate seasonally.  Ours are based
                                          on the spring/summer seasons.)
     [4] - Rare - very difficult to find, maybe only a couple found after repeated visits to the site
     [3] - Uncommon - difficult to find, may not see on every trip but dedicated searching may turn up a few
     [2] - Common - easy to find, should locate a number of them on any given day
     [1] - Abundant - very easy to find, large numbers should be seen on every trip

Data is all intertidal unless noted.

 North & West Beaches


Mytilus complex  [1]



Littorina scutulata  [1]
Littorina sitkana  [2]
Lottia digitalis  [1]
Lottia pelta  [1]
Lottia persona  [2]
Nucella canaliculata  [3]  
Nucella lamellosa  [2]
Nucella ostrina  [2]

Onchidella borealis  [4]


Katharina tunicata  [3]
Mopalia muscosa  [3]


Rosario Beach

Chlamys hastata  [4]  (juveniles)
Chlamys rubida  [4]  (juveniles)
Clinocardium nuttallii  [2]
Crassadoma gigantea  [4]
Crassostrea gigas  [2]
Leukoma staminea  [2]
Macoma balthica  [4]  
Macoma inquinata  [3]
Modiolus rectus  [4]
Mytilus complex  [1]
Pododesmus macrochisma  [2]
Acmaea mitra [4]
Amphissa columbiana  [2]
Calliostoma ligatum  [2]
Ceratostoma foliatum  [3]
Diodora aspera  [3]
Lirabuccinum dirum  [2]
Littorina scutulata  [1]
Lottia digitalis  [2]
Lottia pelta  [1]
Lottia scutum  [2]
Margarites pupillus  [3]
Neostylidium eschrichtii  [2]
Nucella canaliculata  [2]

Nucella lamellosa  [1]
Nucella ostrina  [1]

Cryptochiton stelleri  [3]
Katharina tunicata  [2]

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This page last revised: 5-25-2019