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What is commercial fishing, what are the types of commercial fishing, and why is it bad?



What is commercial fishing, what are the types of commercial fishing, and why is it bad?

Expanding global demand for seafood has driven commercial fishing to new heights, causing the destruction of ecosystems, the pollution of the oceans, and the suffering of billions of animals every single year. It is not just the fish being caught as food who are impacted, but also the people in the communities that depend on them, and a wide array of animals that are caught and discarded as accidental bycatch.


What is commercial fishing?

In 2018 an estimated 96 million tons of fish were caught in fisheries around the world. This massive quantity of fish is only possible due to commercial fishing, a type of fishing that allows a single vessel to catch thousands of fish, often with a detrimental impact on the environment and wild animals. There are a number of different types of commercial fishing, including some that use lines and others that use nets. Regardless of the specific method being used, they are all the same in that they are indiscriminate as to the species of animal being caught. Though fishing boats may fish in areas known to have high populations of the species that they are looking for, they inevitably end up also collecting bycatch — other, nontarget, species. In fact, in 2019 commercial fishing activity directly impacted an estimated 20 million endangered, threatened, or otherwise protected animals.


What are the four most common commercial fishing methods?

The methods and equipment used by commercial fishing vary depending on the species being targeted, the geographic location, how deep the fishing crew want to go in the water, and several other variables.


Fishing with nets

One of the most common methods employed to fish commercially is the use of nets. There are several different nets that can be deployed in this method, depending on the scale and depth of the fishing being done.


Lift net

Lift nets are used both in small-scale and larger commercial fishing operations. Common species targeted include anchovies, scad, and sardines. Generally, lift nets are placed into the water and then a school of fish are attracted, or driven into the area using light or other bait. Once the fish are in place above the net, the net is pulled up and into the boat, capturing the fish inside.

Seine net

Seine nets have bottoms that are weighted down and tops that are fitted with floats. One kind of seine net used to target fish species that spend much of their time midwater such as mackerel and tuna is a purse seine. These nets have bottoms that can be drawn together once the net has been filled with fish, capturing the creatures inside so that they can be pulled onto the boat. Other types of seine nets can be used both from boats or from the shore.


Fishing with lines

Longline fishing is a particularly dangerous method of commercial fishing that frequently results in bycatch. The method consists of a mainline that can stretch for dozens of miles adorned with secondary lines which each sport a baited hook. They can be used at any level within the water depending on the target species, but common targets include tuna and swordfish. The bait is indiscriminate in the species attracted and so catching protected species such as sea turtles, whales, and dolphins is common.


Harvesting shellfish

Shellfish are often caught via dredging. Dredges consist of a metal frame with a collection bag attached. They are dragged along the bottom of the ocean floor either scraping or penetrating the ground. Those that penetrate the ground tend to have water jets that chase animals out of their safe spaces beneath rocks and in crevices. This method is used to capture species that spend their lives in the substrate of the ocean floor such as crabs, oysters, clams, and mussels.


Dredging is destructive for the environment and for many of the species that inhabit it and depend upon healthy reefs and ocean landscapes to survive. If not planned meticulously, dredging can be detrimental to seagrass beds and the spawning grounds of a variety of species. Because dredging frequently takes place in areas where endangered species spend their time, such as Kemp’s ridley, loggerhead, and green sea turtles, as well as many dolphins and whales, these animals frequently suffer from dredging. Turtles can be captured in the dredges and can be harmed within the nets by debris or when dropped on the deck of the boat towing the dredge, while marine mammals can be entangled in lines as well as captured.


Diving

Diving fishing consists of targeting specific species using underwater breathing equipment such as scuba. Most dive fishing is done by small-scale commercial operations that target a small number of high-value species. While the bycatch of dive fishing is limited, as divers are able to identify and capture the target species, the danger to the diver is considerable. Further, one review of the literature surrounding dive fishing found that the fisheries targeted are overexploited.


Does commercial fishing make money?

In 2018, global fishing production had a “first sale” value of $401 billion. Calculated by live weight, over 60 percent of global exports were from lower-income countries. Though the economies of many lower-income countries may benefit from the fishing industry, the health and well-being of their citizens often show detrimental effects.


Why is commercial fishing bad?

Commercial fishing has a range of detrimental effects on the environment, both above and below the water.


Bycatch

Perhaps the most obvious negative outcome of commercial fishing is bycatch, the capture of nontargeted species. Every year approximately 10.3 million tons of catch is discarded as bycatch. Commonly captured creatures include fish, mollusks, corals, sponges, marine mammals, sharks, sea turtles, and even seabirds.


​​Coral reefs

Commercial fishing can negatively impact coral reefs in many different ways. Overfishing by fishing nurseries, taking larger individuals of a species, indiscriminate fishing, and catching fish when they have gathered to spawn all reduce fish populations and jeopardize their future availability and ability to survive. Having a well-balanced and thriving fish population is essential to maintaining healthy reefs. Overfishing can also remove too many herbivorous fish that feed on the algae and help keep coral reefs healthy. Methods of fishing that use explosions to stun or kill fish directly damage coral reefs. Using some types of nets can also damage coral reefs during use. Abandoned nets, called ghost nets, can entangle and dislodge coral.


Environmental risk

Approximately 640,000 tons of commercial fishing gear, deemed ghost gear, are abandoned in the world’s oceans every single year. Ghost gear makes up about 85 percent of the plastic present on the seafloor on seamounts and ocean ridges and within the Great Pacific Gyre. This gear is specifically designed to capture and kill ocean life, something it does successfully even after it has been abandoned by fishing vessels. Up to 136,000 large whales, seals and sea lions are killed by ghost fishing every year. Over 300 sea turtles were found tangled in a single ghost fishing net in Mexico in 2018.


Occupational health and safety

In addition to the dangers for sea life, commercial fishing is also a dangerous occupation for the workers employed within the industry. In fact, dive fishing has been noted as one of the most dangerous occupations in the world. Between 2000 and 2015, there were 117 deaths per 100,000 workers in the commercial fishing industry as a whole in the United States. Among all workers in the country the number of deaths drops to 4 per 100,000 workers. Causes of death include injuries on board, falling overboard, and vessel disaster.