Salmon — British Columbia
Fish harvesters slowly drag a large cone-shaped net along the seafloor to catch a variety of shrimp species. The net is sunk and held open by a long pole also known as a "beam trawl." Larger vessels use “otter boards,” which look like large, heavy steel or wooden doors, to keep the net open. As the net is towed at low speed, hydrodynamic forces push the boards outwards opening the mouth of the net and capturing shrimp in its path. The net is then hauled to the surface using hydraulic winches and a drum. A single tow can net thousands of shrimp along with incidental catch.
Also known as “dragging,” beam trawling uses a large net made of polyethylene to catch shrimp. A large pole, or beam, keeps the mouth of the net open. Floats are attached to the upper mouth of the net to keep it open vertically and weighted “bobbins” are attached to the lower mouth to sink the net. In British Columbia, it is mandatory for shrimp nets to be fitted with grates halfway down to reduce the number of unwanted fish caught. The grates direct fish to a hole through which they escape.
There are 242 fishing vessels that are licensed to catch shrimp using trawls in British Columbia. They range in size from seven to 35 metres. Smaller vessels, typically under 15 metres, use “beam” trawls to catch shrimp. Fish harvesters target small pink shrimp (Pandalus borealis and Pandalus jordani) and sidestripe shrimp (Pandalopsis dispar). They also catch coonstripe shrimp (Pandalus danae), humpback shrimp (Pandalus hypsinotus) and an incidental of spot prawn (Pandalus platyceros).
Bottom trawls disturb habitat when dragged along the seabed, and impacts vary by sediment type and the trawl gear used. Undersized and unwanted species (bycatch) are also unintentionally caught. In British Columbia, shrimp trawlers must use grates on their nets which reduces the amount of unwanted fish caught but allows shrimp to slip through into the net.
The Department of Fisheries and Oceans and Pacific Coast Shrimpers Cooperative Association co-manages the shrimp trawl fishery using a number of measures to address conservation, including:
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The Department of Fisheries and Oceans manages this fishery under an integrated fisheries management plan.
For the most recent shrimp stock status, check the Department of Fisheries and Ocean’s science advisory reports at this link (PDF).
Shrimp caught by bottom trawls are hauled aboard and stored in ice or a mixture of ice and seawater.
The trawl fishery takes place mostly in protected inshore waters in the Strait of Georgia, inlets and fjords, offshore regions of the West Coast of Vancouver Island, and Prince Rupert District. Pink and sidestripe shrimp live mostly on sandy and muddy seafloors. They move up closer to the sea surface during the night to feed on zooplankton and stay close to the bottom during the day, where they are caught using bottom trawls.