The
northern shrimp is one of the animals called crustaceans (crabs,
lobsters, etc.), which have hard outer shells, jointed legs, and
breath through gills, since most of them are aquatic. This
species is pale scarlet, has a pair of compound eyes, and gets 16 cm
long.
It is a good swimmer, like so many of the sam family. It used
appendages on the tail (pleopods) to paddle with great agility.
It is found in the Pacific and Atlantic Oceans. In the Atlantic
all the way from the Gulf of Main, through the Davis Strait, through
East Greenland, and the Norhteast Atlantic, including the Norwegian,
Barents and North Seas. In the Pacific, it extends from Japanese
waters to the Bering Sea, and from the Aleutian Islands to the
Washington-Oregon coast.
Canadian shrimp grounds in the Atlantic are in the Gulf of St.
Lawrence, on the Scotian Shelf, in the Labrador Channels, and the
Davis Strait. Where the greatest populations of the northern
shrimp are to be found, the temperatures of the sea are between 2°C
and 6°C. Sometime these temperature zones lie no deeper than 180
m. There also seems to be relationship between depth and size,
i.e. larger at greater depths.
The northern shrimp migrates both horizontally and vertically.
The former is seasonal and occurs when females seek shallower waters
for spawning, after which the concentrations disperse again. The
latter occurs on a daily basis, probably in the search of small
palagic crustaceans or krill. It is an importan link in the food
chain for many fish species, especially cod. The diminishing cod
stocks have lead to increase in the shrimp stocks. It can be
found at depths between 50 and 700 metres and it prefers soft, muddy
ocian floors to hard ones, where it is sometimes found.
The main concentrations of northern shrimp in Icelandic waters are
found off the northwest, north and northeast coasts. It is
bisexual. First it reaches male puberty, but then changes to
female. Sometimes, when growth conditions are good, it reaches
puberty as female and skips the male stage. The gender of the
shrimp can be detected by the shape of the inner flap of the first
pair of swimmers. |