It is crucial to understand how a fish was caught to ensure its sustainability.
The most often used methods
A fishery is defined by the way it is caught. The cost and efficiency, as well as bycatch, of a fishing operation, are all affected by the gear used. We will cover all the methods by which fish can be taken from the water to your table.
Below is a graph showing the percentage of wild-caught fisheries caught by fishing methods.
Using Nets for Fishing
You probably picture huge, massive nets lifting up schools of fish when you think about commercial fishing. It is not hard to believe! Nets are used to catch more than 80% of the fish. Nets come in a variety of shapes and sizes.
The purse seine fishing method is the most generally used way to catch fish. A boat identifies the school of fish and then, either with an a-frame or small boat, can take one end of the net around the school and return towards the fishing vessel. The net’s ends are connected like drawstring bags and brought into the boat with the fish. Since purse seining is a method of capturing specific schools of fish once they are located, the bycatch rate is very low. Fishing boats may use floating objects such as large floating barrels or rafts to lure fish (fish are fond of structures). Fish gathering equipment (FADs) assist in simplifying processes by decreasing the amount of fuel used and time spent looking for fish schools. They also attract marine animals, which increases the probability of them being caught. More than half of the tuna caught are seen with purse seines. When FADs are used, the bycatch is between 1 and 8%, while without FADs, the bycatch is lower than 1 percent.
Trawling is the practice of pulling a net across the water that surrounds vessels. There are two types of trawls: bottom ones and mid-water-trawls.
Bottom trawls are the process of weighing a net until it reaches the seafloor and then dragging them across the bottom in order to catch fish.
Bycatch is not particularly concerned with bottom trawls; however, the damage to habitats can be. The sandy bottoms, as well as rocky areas, can regenerate quickly after the bottom trawls arrive. However, bottom trawls may negatively impact vulnerable habitats, such as the coral reefs found in deep water and the sponge gardens. A sound fishery management system ensures that bottom trawling occurs in environmentally sustainable areas instead of sites with irreparable habitats.
Midwater trawls trawl nets through the waters off the bottom. Bycatch is minimal.
Gillnets are designed to create a wall that has holes. Fish are unable to see the wall and end up getting stuck. Gillnets do not need an engine-powered boat or engine, so they are often employed in less developed areas.
Gillnets are the most prolific bycatch among any fishing net, yet their use is decreasing. Gillnets are viable in certain situations, such as when salmon are a common sight at choke points, which can be protected from harming other species. Gill nets that aren’t located in a specific area and move in the direction of currents are referred to as drift nets. They also face severe problems with bycatch.
Longlines are fishing lines with hooks that are every couple of feet. They can stretch for miles long.
The amount of bycatch caught in fishing with long lines can vary greatly depending on the fishery. The long lines of halibut fishing in Alaska are a bit tinier source of bycatch, whereas long lines designed to catch tuna have around 20% of bycatch. Problems with long lining are more frequent in fisheries that are close to the ocean’s surface, where seabird turtles and sharks are trapped eating baited hooks. The regulations are higher in capacity countries, where fishery managers may need to use special hooks and weights that limit bycatch.
Poles and Lines
A fishing pole and line catch fish in a single. There is no need to worry about the bycatch.
Dredging is the same as bottom trawling; however, rather than a net, the rake made of metal is used to gather bivalves and shellfish, which are then buried within the substrate, such as scallops, mussels, or clams.
The amount of bycatch is not high; However, similar principles apply to bottom-trawling. Sound management of fisheries will ensure that dredging occurs in areas with durable sandy soil and not in areas with lost habitat.
Traps and Pots
Traps and Pots are employed to capture invertebrates such as lobster and crab. Traps and pots are lowered to the bottom of the ocean with baits to attract lobster and crab. Once they are inside, they are unable to escape and are dragged away from the shore after the fishermen return.
The problem of bycatch is not that big. However, gear can get scattered, or fishermen don’t remember where they placed their traps. This has resulted in some whale entanglements, particularly on the West Coast of the U.S. Certain states have begun offering rewards to those who find escape traps and pots.
Divers catch certain commercial fisheries like geoduck, sea urchin, and sea cucumber.