How to Distinguish from Similar Species: There are no similar species near Rosario.
Geographical Range: Gulf of Alaska to southern California
Depth Range: Shallow subtidal to 70 m
Habitat: Sand and mud bottoms
The entire central
part (rachis) is said to be one large polyp. Smaller,
polyps open into it and pump water in an out as needed for expansion or
contraction. Produces a strong greenish luminescence when
Preyed upon by several nudibranchs, including Hermissenda
crassicornis, Armina californica,
and Tritonia festiva,
of the seastars Dermasterias imbricata, Pycnopodia
aequalis, Hippasteria phrygiana, and Crossaster papposus. The
sea pens may rapidly
burrow into the sediment when contacted by a predator.
do not appear to burrow when exposed only to seawater which contained a
predatory seastar, they were more likely to burrow after contacting a
seastar if they had already been exposed to its smell. This
responds to different predators differently.
Kozloff 1987, 1996
Flora and Fairbanks, 1966
General Notes and Observations: Locations, abundances, unusual behaviors:
In our experience this species is usually found in quieter water such as behind Whidbey Island. Years ago there was a small colony in Rosario bay. The colony disappeared and no individuals were seen for 5-10 years. In the 1980's some students working on a project harvested some individuals from behind Whidbey Island. After the project they returned them to Rosario Bay. Since that time the species has been becoming more abundant in the bay again.
In my experience, if this species is not placed into sand or mud in the aquarium, it usually has a problem with its lower stalk which becomes hyperinflated.
A short video of this species can be found at: http://www.racerocks.com/racerock/archives/vidseapen2a.htm
I photographed this individual at 50 ft depth in Burrows Bay. Photo by Dave Cowles 2019
Authors and Editors of Page:
Dave Cowles (2005): Created original page