Salmon: Fishing and Aquaculture

May 3, 2021Lu Shegay

Introduction

Salmon is a species of ray-finned fish in the family Salmonidae, which includes other fish, such as trout, char, grayling, and whitefish. These fish are native to the North Atlantic and the Pacific Ocean, and they are intensively farmed in lots of countries across the globe. Salmon are migratory: they hatch in freshwater, migrate to the ocean, and then return back to freshwater. Salmon are facing many threats from human activities, and the major ones include fishing and overfishing activities for various purposes, such as food consumption, aquaculture, trade.


General Characteristics

There are a few species of salmon, such as the Atlantic salmon, which includes Chinook salmon, Chum salmon, and Coho salmon. Another species is the Pacific salmon, which includes Masu salmon, Pink salmon, and Sockeye salmon. Among all of them, Atlantic salmon has been assessed by the IUCN Red List and was classified as Vulnerable species in 2014. Red-spotted Masu salmon is listed as Endangered.


Salmon fish hatch their eggs in freshwater streams, and only a few species of salmon remain in freshwater habitats during the entire life cycle. Salmon are migratory fish, so they usually migrate to the ocean for maturation and spend approximately 1-5 years in the open ocean. The species of Atlantic salmon, for instance, spend about 1-4 years in the sea. Although salmon do not spend much time in the freshwater area, this area still plays a significant role for them as they feed on terrestrial and aquatic animals, amphipods, crustaceans.

"Red salmon when returning from the ocean are sometimes referred to as bluebacks before they become red and their heads turn green. NPS Photo/M. Bradburn" by KatmaiNPS is marked with CC PDM 1.0

Threats

Salmon are threatened mostly by fishing, both commercial and recreational. According to the FAO, since 1990, the global capture of salmon was estimated at 1 million tonnes per year.


When it comes to farmed animals, the only land farmed animals are taken into consideration, however, aquatic animals can suffer in farming too. Salmon is one of the most used species of fish in farming. They are kept in sea cages that are made out of steel or plastic.


Fishing

Salmon are caught by a wide variety of methods, the most common are, of course, nets. Other methods are gillnets - “walls of stationary or drifting netting that are almost invisible to fish.”


“Set, drift, and trammel gillnets use different configurations of floats and weights to suspend the netting more or less vertically. Encircling gillnets are set in shallow waters, and noise or another means is used to entangle the fish in the netting. Fix gillnets are stretched between two or more stakes that are driven into the seabed in the intertidal zone.


Gillnets can accidentally catch vulnerable ocean animals like sea turtles, marine mammals, and sharks. These impacts can be reduced by setting the gillnets deeper in the water column to allow room for animals to swim over and adding gear like pingers, which warn passing marine mammals.”


Another method of fishing salmon is trolling lines. “Trolling lines lure fish with moving fishing lines with baited hooks. Several trolling lines are often towed at the same time, and equipment called outriggers keeps the lines away from the boat’s wake. The lines are hauled in by hand or mechanically using small winches. Trolling lines are used to catch a variety of species such as mackerel, rockfish, salmon, and tuna. This fishing method has low catch of unwanted marine life.”


Aquaculture

As for the farming methods, salmon are kept in pens. There are more hundreds of marine and freshwater species of aquatic animals that are farmed at present. All of the seafood comes from farming, not wild, except for amateur fishing, of course.


“Pens are structures that hold farmed fish in open water as they grow. They’re made with wooden, mesh, or net screens, which allow water to flow freely through them. Net pens can be in marine waters to farm species such as salmon and trout or freshwater to farm species such as tilapia and trout. Types include pens, which are fixed to the bottom in shallow waters. Net pens are enclosed on the bottom and sides. Submersible net pens are fully enclosed and submerged, usually in offshore marine waters.”


Read more: Fishing and Farming Methods

"Salmon at the underwater dome at The Seattle Aquarium" by Merelymel13 is licensed under CC BY-SA 2.0

Sentience

It might be surprising for some people, but fish can feel pain and this statement was proven. Will this help elevate their status in the legal system? The first thing is done - fish are officially proven to feel pain, meaning they are too sentient beings like many other animals. And despite those facts, fish species are excluded from legal protection.


“At the anatomical level, fish have neurons known as nociceptors, which detect potential harm, such as high temperatures, intense pressure, and caustic chemicals. Fish produce the same opioids — the body’s innate painkillers — that mammals do. And their brain activity during injury is analogous to that in terrestrial vertebrates: sticking a pin into goldfish or rainbow trout, just behind their gills, stimulates nociceptors and a cascade of electrical activity that surges toward brain regions essential for conscious sensory perceptions (such as the cerebellum, tectum, and telencephalon), not just the hindbrain and brainstem, which are responsible for reflexes and impulses.”


“Fish also behave in ways that indicate they consciously experience pain. In one study, researchers dropped clusters of brightly colored Lego blocks into tanks containing rainbow trout. Trout typically avoid an unfamiliar object suddenly introduced to their environment in case it’s dangerous. But when scientists gave the rainbow trout a painful injection of acetic acid, they were much less likely to exhibit these defensive behaviors, presumably because they were distracted by their own suffering. In contrast, fish injected with both acid and morphine maintained their usual caution. Like all analgesics, morphine dulls the experience of pain but does nothing to remove the source of pain itself, suggesting that the fish’s behavior reflected their mental state, not mere physiology. If the fish were reflexively responding to the presence of caustic acid, as opposed to consciously experiencing pain, then the morphine should not have made a difference.”


Read more: It’s Official: Fish Feel Pain


Conclusion

Fish are one of the aquatic creatures that receive less consideration and attention from the public. Some take into consideration only cute animals or big animals depending on various opinions. While eliminating fishing completely is impossible at least right now, the proper management of fish stocks is the first step in protecting the species from going extinct. Moreover, fish are capable of feeling pain, suffering, and fear, which gives us a message that each of us can make a difference. There is a way to protect fish, and the simple one is to go vegan because not only fish suffer, other aquatic animals are affected too due to their dependence on one another in the food chain. The first and most important step has been made - fish were recognized to feel pain. Now it is time to urge the government to include them in legal protection.

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