Spot prawn

Pandalus platyceros

Order: Decapoda

Family: Pandalidae

Genus: Pandalus

The Spot prawn is the largest shrimp species found in Canada’s Pacific waters. It has a reddish-brown body with white horizontal lines on the carapace and distinctive white spots on the first and fifth abdominal segments—hence the name. These prawns have long antennae, large black eyes, and slender legs adapted for crawling along the sea floor.

HEAD AND BODY LENGTH

Typically 16 to 25 centimetres (6 to 10 inches), with females generally larger than males

TAIL LENGTH

Forms about one-third to half the body length

WEIGHT

Typically 30 to 50 grams (1 to 2 ounces) per adult prawn

Conservation Status: IUCN

Distribution

Spot prawns are native to the cold, clean waters of the North Pacific, with large populations found off the coasts of British Columbia, Alaska, Washington, and California.

Habitat

Found on rocky or muddy seafloors at depths ranging from 10 to 500 metres. They prefer cold, oxygen-rich waters and often shelter among rocks, sponges, and algae.

Diet

Omnivorous scavengers, spot prawns feed on plankton, small crustaceans, algae, worms, and organic detritus. They play a vital role in the marine food web, both as predator and prey.

Reproduction

Spot prawns are protandric hermaphrodites, meaning they begin life as males and later transition to females—typically after one to two years. Females carry fertilized eggs under their abdomens for several months before hatching. This reproductive strategy helps support population balance and genetic diversity.

Adaptation

Camouflage colouring helps blend with rocky seabeds
Long antennae detect predators and navigate in dark or murky water
Swimmerets on the underside of the tail help females aerate their eggs
Flexible reproductive biology supports population resilience

Threats to Survival

While not currently endangered, threats include:

Habitat disturbance from bottom trawling (though most spot prawns are caught in traps)
Ocean warming and acidification
Bycatch in less selective fisheries
Pollution in coastal waters

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