Fisheries science: Bottom Surveys

Multispecies bottom trawls
Weighted nets are dragged along the sea floor to collect species living on or near the sea floor, such as groundfish (like halibut) and crustaceans (like shrimp). These are used in all regions across Canada.

Traps
Baited traps are often used to catch crustaceans (like lobster and crab) that live near the bottom of the ocean. Traps often have exit areas that allow for small individuals to escape. They are connected to the surface through a lead line and buoy, for retrieval.

Longlines
Longlines have a long central line with baited hooks spaced at regular intervals off of this main line. Longlines can be set either near the surface to target pelagic mid-water species (like tuna) or on the sea floor to target benthic deep-water species (like halibut), as shown here.