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Puget
Sound Shrimp
More than 80
shrimp species inhabit Washington waters. Only seven species though,
are regularly captured for consumption by sport harvesters. Almost
all sport shrimp harvest takes place in Puget Sound or its connecting
waters.
All seven harvested
species belong to the family Pandalidae, and share similar
biology and life history. Shrimp of this family have a unique reproductive
cycle, maturing first as males, then changing sex in later years
to reproduce as females.
Puget Sound
shrimp spawn in late summer or fall. Eggs develop in the female
prior to spawning, and can be seen as a dark band just under the
shell on the head. Shortly after mating, eggs are extruded to the
underside of the abdomen, where they are fertilized by a packet
of sperm previously obtained from the male, then attached to the
female's specialized legs. The female carries the developing eggs
until they hatch in early spring. Newly hatched shrimp larvae are
small (about 3/16 of an inch, or 5mm), planktonic (free floating,
unable to swim against currents), and bear only a superficial resemblance
to adults.
About three
months after hatching, larvae gradually start to take on the appearance
and habits of adults. The larvae continue to develop, maturing as
males within 18 months of hatching. They reproduce as males for
one or two seasons before transforming into females for the next
fall's mating season. Females reproduce for one or two seasons,
and do not seem to survive long after their final brood is hatched
(at age 4 or 5 years).
The proportion
of shrimp changing sex from male to female varies from year-to year.
A few individuals will skip the male phase and spend their entire
lives as females. Recent studies indicate that increased fishing
pressure or high natural mortality can induce males to change into
females at a younger age, or completely skip the male phase. This
reproductive strategy may help to ensure that there is an adequate
supply of egg-producing females each year.
Shrimp are
found primarily on or near the bottom, but make daily migrations
through the water column in search of food. They have been found
at depths greater than 1,000 feet, but are most frequently captured
at depths of 30 to 300 feet.
Adult shrimp
are omnivorous, feeding on marine worms, small crustaceans, large
planktonic organisms, sponges, and dead animal and plant material.
In turn, a variety of fish prey on shrimp, including cod, lingcod,
hake, flounder, halibut, dogfish, skates, and other bottom fish.
NOAA Kodiak
Laboratory webpage has a very good shrimp species comparison photo.
Shrimp
Fishing Gear
Shrimpers
in Puget Sound use pots of various sizes and designs. Pots are normally
constructed with two or four entrance tunnels sloping gently inward
to a circular opening of about three inches in diameter. Shrimp
pots are available at many sporting goods stores, though many shrimpers
choose to make their own. Whether you choose to buy or build your
own pot, consult the Washington Department of Fish and Wildlife
Fishing in Washington regulations pamphlet for restrictions on pot
design and mesh size.
Canned fish-flavored
cat food is the most popular bait used for shrimping in Puget Sound.
Baits such as fresh or frozen fish (whole or ground), clams, and
oysters are also used with some success. Cat food cans should be
punctured on both sides and ends and placed in the pot as bait.
Cat food and other baits may also be placed in bait containers and
secured to the bottom of the pot between the entrance tunnels.
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