shrimp has the typical
extremely short rostrum
characteristic of many crangonids (photo).
is smooth and has a median dorsal spine but no submedian spine (photo).
Abdominal segment 6 has no longitudinal dorsal carinae
(photo) but the
underside does have a median
Abdominal segment 5 has no
spines on the upper posterolateral margins (photo).
The inner flagellum
of antenna 1 is longer than the outer flagellum. The antennal
scale is more than twice as long as wide, has a narrow lamella,
and its spine
is as long as or longer than the lamella (photo).
The scale is shorter than the telson.
Length to 6.5 cm.
Crangon alaskensis Lockington,
Common name(s): Northern crangon
shrimp; Alaskan bay shrimp,
|(Crangon alaskensis from 100 m
depth, San Juan Channel, WA.
About 5 cm long.
|(Photo by: Dave Cowles,
How to Distinguish from
Similar Species: Crangon
nigricauda has a shorter antennal scale and spine and is much
Bering Sea to San Diego,
Depth Range: Intertidal
to 275 m.
This species seems to be found more often in deeper, shelf waters than
near the intertidal zone.
often live on sand,
which they often burrow into.
This shrimp is
one of the crangonids I most commonly find in 100 m depth trawls in the
San Juan Channel. Crangonids are often parasitized by bopyrid
such as Argeia. Crangonids are active
predators, eg. on polychaetes.
In Puget Sound some shrimp appear to be hybrids between C
and C. nigricauda.
and Carlton, 1975
Joana, Claudia Moreira, Fabiana Freitas, and Henk W. van der Veer, 2012.
Short review of the eco-geography of Crangon.
Journal of Crustacean Biology 32:2 pp 159-169
Roberts, James O., 1965. The anatomy and histology
of the eyestalks
of the Alaska brown shrimp Crago alaskensis
Masters thesis, Walla Walla College. 23 pp.
General Notes and
Observations: Locations, abundances,
We frequently catch this species in 100 m depth trawls in the
Most crangonids have a very stubby rostrum,
seen here as the small "horn" between the eyes for Crangon
As with all Crangonids, the first pereopod
of Crangon alaskensis is subchelate
and the carpus
of the second pereopod (visible just above the chela) is simple rather
of the 5th pereopod
is not broad and flattened.
is smooth and has one median spine a short distance behind the eyes, as
can be seen silhouetted in this view from the right side.
The 5th segment of the abdomen (left full segment in this photo) has
no spines on the posterolateral margin (right edge of segment),
and the 6th segment (middle of photo) has no longitudinal dorsal
are to the right.
The ventral side of abdominal segment 6 has a median
groove, visible as the light-colored area in this photo.
scale of the second antennae, being held out by my finger in
is more than twice as long as wide and the spine on the end (left side
of scale) is longer
than the flatter
lamella (right side of end of scale)
A view of the whole, live animal fom which the parts above were
Photo by Dave Cowles, July 2005
Authors and Editors of Page:
Dave Cowles (2005): Created original page