Bull kelp Photo: Jim Ramaglia
Description: Bull kelp is best known for the long, smooth, brown
bull whips that wash up on beaches in fall and winter. This long
stipe, or stalk, leads on one end to a bulbous gas float, attached
to long, flat, leaf-like blades. At the other end of the stipe
is a holdfast - a disc-shaped, root-like structure that adheres to
substrates at depths to 60 feet. Boaters know kelp for the dense
floating beds that mark shallow rocks and reefs.
In the Whatcom County maps depicted above, kelp beds are indicated
by blue shading. This data was provided by Washington State DNR
and Whatcom County PDS. The maps were created by Anchor Environmental.
Distribution: Kelp is found on the Pacific Coast from Southern California
to Alaska's Aleutian Islands, thriving in the turbid subtidal waters
of ocean coasts and straits. More versatile than the perennial
giant kelp of rocky ocean shorelines, bull kelp grows on substrates
of in Puget Sound and on boulders and rock in the straits. In Whatcom
County, bull kelp is most typically found along the Cherry Point
Life cycle: The fastest growing seaweed in the world, bull kelp
can grow from a tiny spore to a 120 foot mature plant in a single
season. Although in Puget Sound waters, bull kelp will typically
just reach 30 feet in length. On the blades of mature kelp, spore-forming
patches, called sori, develop and sluff off, leaving holes or notches
in aging blades. These heavy patches often fall near the parent's
base, but some may drift a distance to release their spores in
new territories. Kelp typically break from their holdfast during
storms, die and wash up onto beaches, ending their life after just
Rockfish in a kelp bed. Photo: Jim Ramaglia
Ecology: Large kelp forests provide structure for a
wide variety of sea creatures. Small crustaceans called isopods
on the blades, while other types of plankton prosper in the
waters calmed by thick kelp stands. The abundant food and shelter
predators make kelp communities valuable habitat for juvenile
salmon, rockfish and surf smelt. Herring that spawn along Cherry
are unique in their use of bull kelp as a spawning surface.
The calmed waters of the kelp beds serve as refuges for seabirds
such as ducks, grebes and gulls which also take advantage of the
food reserves within. At the base, kelp holdfasts and other algae
form a diverse understory with urchin, shrimp, fish and other creatures.
Particles sloughed off the decaying ends of kelp blades provide a
valuable food source for filter feeders like Pacific blue mussels.
In addition, masses of dead kelp washed ashore provide food and shelter
for communities of scavengers like crabs and beach hoppers, which
are food for shorebirds and other life.
Economic Value: Kelp does not recover well from harvest so kelp
is protected from collection in the Puget Sound. An important economic
value of kelp forests in Whatcom County has been the habitat provided
for salmon, herring and other forage fish, which have been commercially