Fishing is the act of catching fish. This term is often used to describe the catching of other aquatic life, including cephalopods (like squid), crustaceans (like lobsters and crabs), and shellfish (like oysters and scallops). There are various types of fishing, including traditional fishing, commercial fishing, recreational fishing, fish farming, blast fishing, cyanide fishing, and shark finning.
During the Stone Age, fishermen used hooks made of bone, stone, and wood as well as rods made from branches. Over time, these hooks were replaced with bronze and copper, and the rods were replaced with sturdier, more sophisticated pieces of wood. Fishermen who use a rod and hook are referred to as "anglers."
It is thought that fishing evolved into a recreational sport in the 15th century.
Fish farming, also known as aquaculture, has been around for more than 4,000 years. Aquaculture now supplies about one-third of the world's aquatic species, many of which include fish, and the value of this global industry is about $50 billion.
Many organizations and agencies, including the U.S. Fish and Wildlife Service (USFWS), the U.S. Environmental Protection Agency (EPA), the National Oceanic and Atmospheric Administration (NOAA), and the International Game Fish Association (IGFA), provide information about fisheries and regulations of current fishing practices and promote awareness about illegal and prohibited fishing practices.
In 2001, the USFWS sponsored a survey to evaluate the previous five years of fishing activities of more than 34 million people. About 28 million engaged in fresh-water fishing, while the remaining preferred salt-water fishing.
Traditional fishing: Traditional fishing involves the use of historical techniques or equipment, such as spears and gill nets, to catch fish.
Before traditional fishing equipment was invented, humans would use their hands along the shores of water bodies to catch fish and other aquatic animals near land. This technique is known as gathering. Gathering is thought to be one of the oldest forms of fishing, and it is still used today to catch echinoderms (like sea urchins), mussels, and snails. Additionally, people may use their feet to locate African lungfish and catfish that are buried in the mud.
Tackle: Fishing tackle is a general term used to describe typical fishing equipment, including hooks, lines, rods, traps, spears, and nets.
Spearfishing: Spearfishing is an ancient form of fishing in which fishermen use a spear or an arrow to catch fish. Early civilizations used sharpened sticks to spear fish.
Spearfishing has evolved into a sport and is often accompanied by diving, snorkeling, or scuba diving. Modern-day spearfishing has become more advanced with the development of the spear gun, which is outlawed in some areas.
Artisan fishing: Artisan fishing is a form of traditional fishing that applies to island and coastal ethnic groups who use rod and hook, arrows, harpoons, and nets to catch fish for food. The fish caught in artisan fishing provide an inexpensive food source to the coastal populations.
Commercial fishing: Commercial fishing involves the capture of fish for commercial sale. Factory ships and large nets are used in commercial fishing to provide efficient methods of capturing fish.
Bottom trawling: Bottom trawling involves towing a trawl (a large fishing net) along the ocean floor. This method is used in commercial fishing to capture large amounts of fish along the ocean floor, including certain species such as cod, flounder, haddock, rockfish, and shrimp. There are two main types: beam trawls and otter trawls.
Beam trawls have a ridged bar that allows an open net, while otter trawls have "doors" (which may weigh up to six tons) that are angled to create a water force that keeps the net open. In other areas, two boats are used to maintain an open net.
The net used in bottom trawling may be up to 55 meters across and 12 meters high. Large nets are used to catch fish such as flatfish, gadoids, and rockfish, while smaller nets are used to catch crustaceans such as shrimp.
Bottom trawling is controversial because the heavy nets may damage the ocean floor and deep-ocean habitats, including coral reefs.
Gillnetting: Gillnetting uses a type of mesh netting to capture fish along the ocean floor. The gill nets may be up to 100 meters in length and nearly three meters wide. Many nets are tied together in a line to catch certain species such as gadoids, flatfish, rays, and skates. There are several ways that fish may be caught using gill nets. A fish may be snagged (the mesh is just behind the fish's eye), gilled (the net is caught behind the gill cover), wedged (the mesh is around the fish's body above the dorsal fin), or entangled (the fish is caught in the net by the fin, teeth, or other projections).
Research suggests that gill net fisheries are responsible for thousands of unintentional marine animal fatalities each year. Many animals, especially marine mammals like dolphins and whales, mistakenly get caught in gill nets. It is suggested that thousands of marine species, including dolphins and whales, are killed annually due to gill net entanglement. It is also suggested that certain species, including bottlenose dolphins, are unable to detect the nets in time to avoid collision, but evidence is conflicting. Although interactions between the dolphins and the gill nets may be common, entanglement may be less common, based on a study conducted in North Carolina that used a digital video camera to observe interactions. Between May and June 2002, there were 56 combined fish-net encounters and interactions but only nine entanglements.
The National Marine Fisheries Service (NMFS) has implemented regulations to protect northern whales from injuries and deaths due to entanglements in gill net gears off the coast of southeastern United States. Under these regulations, gill net fishing is prohibited during whale calving (birthing) season, which lasts from November until April. The NMFS also regulates gillnetting in other areas in an effort to protect other species, such as swordfish along the coast of Southern California.
Fish farming: Fish farming, also known as aquaculture, has been around for more than 4,000 years. Hieroglyphics suggest that Egyptians used this method and attempted fish culture. Romans participated in raising fish and cultivating oysters, while Hawaiians constructed fish ponds about 1,000 years ago.
Marine aquaculture involves the cultivation of marine species, such as salmon, shrimp, clams, and mussels. Freshwater aquaculture involves the cultivation of freshwater species, including tilapia, catfish, and trout.
In 2004, the United States ranked 10th in total aquaculture production, according to the United Nations Food and Agricultural Organization. Marine aquaculture makes up about 20% of the total aquaculture in the United States, most of which consists of molluscan shellfish cultivation (such as clams, mussels, and oysters). The top competitors include Chile, China, India, Indonesia, Japan, Norway, and Thailand.
Most of the fish farming production in Asia consists of freshwater fish, such as tilapia and carp, but much of East Asia participates in the cultivation of high-value marine fish.
Most of the farmed marine species are carnivores and need wild fisheries in order to provide fish meal and fish oil used in the feeds. Farmed freshwater fish tend to be herbivorous or omnivorous.
Salmon aquaculture began in Norway in the 1970s and has now expanded worldwide with farmed salmon global production, making up about 60% of the frozen and fresh salmon sold internationally.
With salmon aquaculture production booming, aquaculturists are farming other species that are depleted due to overfishing, including Atlantic cod, bluefin tuna, Atlantic halibut, and mutton snapper.
Blast fishing: Blast fishing is a form of fishing that uses explosives to kill schools of fish. The practice has existed for centuries and is still conducted in many countries and islands around the world.
Previously, this practice was permitted for the research of specific species such as whales, crocodiles, and sharks. Today, the practice is illegal but still very prevalent in areas such as the Philippines.
This practice is employed because the use of explosives ensures a larger catch, but the explosives are used only when a school of fish or large fish is detected.
The most common blast device used is a homemade bomb consisting of a bottle layered with powered potassium nitrate and pebbles. Other bombs are made of commercial fuses, gasoline, sugars, and fertilizers. The explosives may weigh up to 15 pounds and are relatively inexpensive to create.
The explosion creates initial high-intensity shock waves, which are then followed by smaller, lower-intensity waves. The generated waves vary depending on the depth, distance, and temperature of water, along with the type and size of the explosives used.
The blast indiscriminately kills everything in the area, including the surrounding habitat. These bombs are detrimental to the environment, leaving craters that are a few meters in diameter and capable of killing more than 50% of the coral (which is endangered) in the area of detonation. It may take hundreds of years for the coral reef's structure to be reconstructed after a blast.
The fish that are most vulnerable to this practice are bony fishes. Most bony fishes have swim bladders to help adjust buoyancy, and the waves produced by the blast cause an increase in pressure within their bladders, resulting in injury and death. Therefore, animals without swim bladders, such as sharks and rays, are more resistant to this practice.
Typically, fishermen collect the dead fish that float to the surface, while divers gather the remaining fish.
A significant risk of injury to the blast fishermen accompanies this practice, but many fishermen continue the practice. In addition, numerous cases have been reported in which bystanders, such as scuba divers, are hurt or killed unintentionally during a blast.
Recreational fishing: Recreational fishing includes fishing for sport or competition. The derived products (fish) are not available for sale. According to the National Oceanic and Atmospheric Administration (NOAA), roughly 12 million Americans participate in recreational fishing. This activity also generates more than $30 billion and provides about 350,000 jobs.
In 2002, recreational landings, not including large industrial fisheries, accounted for 10% of the total fish caught in the United States. It affects some of the most valued and overfished populations, including bocaccio, red drum, and red snapper.
Licensing requirements and fishing limitations have been placed in some areas to prevent shamateurism. Shamateurs are fishers who pose as recreational anglers to avoid paying for a commercial fishing license and actually rely on their fishing financially.
The Marine Recreational Information Program (MRIP) is a system involving coordinated data collection to address regional needs. Currently, the MRIP is investigating the amount of recreational trips, the species and amounts of fish being caught, and when and where the fish are being caught. The MRIP is also evaluating the economic effect of recreational fishing on a local, regional, and national basis.
Cyanide fishing: Cyanide fishing, also known as poaching, is a method that uses sodium cyanide to stun reef fish. It is proposed that the cyanide produces an anesthesia-like reaction due to severe oxygen depletion within the cells.
This practice originated in the Philippines, and it is estimated that Filipino fishermen used about 150,000 kilograms of sodium cyanide a year. This illegal practice has expanded into a large-scale method of providing live fish all over Southeast Asia.
Cyanide fishing provides an inexpensive and effective way to collect fish. Fishermen crush sodium cyanide pellets into bottles filled with seawater. This concentrated formulation is then squirted into the crevices of the reef where fish hide, and temporarily stuns the fish, allowing for easy capture. The catch is then brought back to the ship, and the edible fish are placed in seawater for rinsing and transport. In some areas of the world, bleach is used rather than cyanide to create a similar solution to catch reef fish and crustaceans.
Young fish and coral polyps are the most vulnerable to the cyanide solution, while adult fish are able to withstand higher doses. The greater the cyanide concentration and time of exposure, the longer the time to recovery.
Nontarget structures and organisms are adversely affected by the concentrated cyanide solution. The cyanide often leads to the death of nearby microorganisms, fish, eggs, larvae, and corals. If the fish flee into crevices, the divers may hammer the reefs in order to collect the stunned prey, which leads to damage to the marine environment that may take hundreds of years to recover. In humans, there is the risk of cyanide poisoning, which may lead to unconsciousness, temporary or permanent disability, and possibly death.
Much of the live reef fish that are captured using this method are sold to specialty restaurants. Although cyanide fishing is illegal in many countries, the high profit associated with live food fish and weak law enforcement keep this business booming, valued up to $1 billion annually in East Asia.
Cyanide fishing is also used to catch fish for aquariums. Research suggests that more than 70% of the aquarium fish that are exported from the Philippines are caught using cyanide. The combination of cyanide and the stress postcapture has been shown to cause death in about 75% of the organisms caught within the last 48 hours. Since there is such a high risk of death, a large number of fish are needed to balance the postcatch death rate.
Shark finning: Shark finning is the process in which sharks are caught and their fins are removed. The most commonly removed fins are the dorsal, pectoral, and lower caudal fins. However, the removal of other fins, including the anal, upper caudal, and second dorsal fins, has been observed. Since shark meat is considered low value, the finless sharks (often still alive) are thrown back into the ocean. Since sharks cannot swim without their fins, they sink to the ocean floor and perish.
Shark finning is prevalent, with no international limits outside of Antarctica. Hong Kong has been known as the center of the shark fin market for many decades. It has been estimated that Hong Kong's contribution to the trade has ranged between 50% and 85%.
Shark fin soup is a popular Chinese meal that is served in restaurants worldwide. This dish is thought to promote general well-being and has been used to treat heart disease, arthritis, psoriasis, and some forms of cancer.
Nearly 8,000 tons of shark fins are processed annually for shark fin soup. For six servings, about one pound of shark fins is needed, and the high demand for this ingredient is associated with the death of an estimated 38 million sharks annually.
People have used shark fins for their medicinal properties for centuries in Asia in the forms of powder, tablets, or whole fin. In more recent years, shark fins have become more popular in western medicine. Shark fins, particularly the cartilage, are suggested to have anticancer properties. Shark cartilage lacks blood vessels and contains substances that inhibit angioneogenesis, the process of developing new blood vessels, thus potentially reducing tumor progression. However, there is a lack of scientific evidence supporting the use of shark fins for medical conditions.
Sharks are thought to serve as key predators in the marine environment, a needed role in order to maintain and stabilize food webs. The development of shark fin markets in the 1990s led to a mortality rate of more than 80% of the sharks that were caught.
Oceana, an international organization focused on ocean conservation, is working to protect shark populations by pushing for finning bans, shark species management, and a reduction of the demand for shark fin soup and cosmetic products containing squalene.
Due to the concern of shark conservation, the United States and Australia have established bans on landings of shark fins. This legislation may potentially reduce the mortality rate of coastal sharks by a significant amount.
WildAid is a nonprofit conservation organization that aims to eliminate illegal wildlife trade. WildAid established the Shark Conservation Program to help reduce threats to the shark population, including overfishing, overconsumption, and harmful practices such as finning. International Asian fleets continue to use this process, which hinders the ability to reduce pelagic shark mortality.
Fugu fishing: Fugu has been consumed for numerous years in Japan. Fugu (Takifugu) is a genus of puffer fish and is also the name of a Japanese dish made from the puffer fish meat. Puffer fish contain poison that could be lethal if prepared incorrectly, which is why it is considered a delicacy in Japan. When cleaned properly, fugu flesh and musculature is an edible delicacy.
Fugu, along with other fish of the order Tetraodontoidea, is exported from Japan, China, the Philippines, and Mexico.
Fugu fish are considered one of the most poisonous marine animals. The fish's gonads, intestines, liver, and skin contain tetrodotoxin, a lethal neurotoxin that is 1,200 times more lethal than cyanide. It is estimated that ingestion of this toxin leads to death in about 60% of the people who ingest it.
The Fugu Research Institute reports that about 50% of the poisonings are related to the consumption of the liver, 43% from the ovaries, and 7% from the skin.
Symptoms of toxicity include tingling of the tongue and mouth, vomiting, dizziness, convulsions, low blood pressure, slow heart rate, fixed dilated pupils, and paralysis eventually leading to death within 24 hours (secondary to respiratory muscle paralysis). There is no antidote to this poisoning.
In the United States, personal importation of fugu is prohibited; however, the U.S. Food and Drug Administration (FDA) permits the importation of fugu for preparation in Japanese dishes by certified fugu chefs on occasion.
The high demand for fugu has led to overfishing and the need for strict protection to prevent further depletion. Fugu has been farmed in the Pacific Ocean in floating cages. Farmed fugu fish may contain less toxin or no toxin altogether because the fish's diet is regulated. Scientists have successfully bred nontoxic fugu fish, which are said to taste the same and be safe.
Food source: Originally humans caught sufficient amounts of fish needed for their day-to-day needs. Eventually, fish were used to barter for things, and the demand for fish increased.
Fish provide high-quality protein that is abundant with essential amino acids and minerals.
Roughly 40% of the fish humans consume directly originates from commercial farms.
Medicine: People have used fish for their medicinal properties for many years. Fatty fish, such as salmon and tuna, contain omega-3 fatty acids, which are thought to have beneficial effects on the heart. They may help to reduce the risk of arrhythmia, decrease triglyceride levels, decrease the rate of growth of atherosclerotic plaque, and lower blood pressure.
Docosahexaenoic acid (DHA), a specific omega-3 fatty acid, is suggested to provide benefit to the brain development of infants. Therefore, pregnant women, nursing mothers, and women of childbearing age are encouraged to consume fish as a source of DHA. However, fish may contain methylmercury, and caution is warranted in young children and pregnant/breast-feeding women.
Fish are also rich in vitamins such as riboflavin (vitamin B2); calcium; phosphorus; and minerals, including iron, potassium, and zinc.
Shark fins, particularly the cartilage, are suggested to have anticancer properties. Shark cartilage lacks blood vessels and contains substances that inhibit angioneogenesis, the process of developing new blood vessels, thus potentially reducing tumor progression.
People have used shark fins for their medicinal properties for centuries in Asia in the forms of powder, tablets, or whole fin. In more recent years, shark fins have become more popular in western medicine. Currently, there is a lack of scientific evidence to support the use of shark fins for medical conditions.
Recreation: Recreational fishing, also called sport fishing, is done for pleasure or competition. Often the catches are logged, and the recreational fishermen participate in competitions.
There are rules and regulations, along with licensing restrictions, which maintain standards describing how fish may be caught. These laws typically prohibit the use of certain equipment, such as nets, and the catching of fish without hooks in the mouth. These regulations vary from state to state, but the National Marine Fisheries Service (NMFS), an agency of the National Oceanic and Atmospheric Administration (NOAA), has adopted a code of angling ethics to ensure sound actions and attitudes. Angling is the technique of catching a fish with a hook that is often used in recreational fishing. Most recreational fishing involves a rod with a reel, line, and hook, along with bait used to lure fish.
Catch and release is a method used in recreational fishing in which fishermen return the fish to the water.
Sport fishing is a form of recreational fishing in which the incentive is the art of finding and catching fish rather than the financial value of the fish. Also known as game fishing, sport fishing may involve the retrieval of mackerel, marlin, shark, sailfish, and tuna.
Overfishing: Overfishing occurs when so many fish are caught that the remaining population is unable to reproduce enough to maintain the usual population. In order to maintain adequate populations, the fishing communities have been protected.
The United Nations reports that up to 95% of commercial cod, haddock, hake, and flounder populations have been depleted in the northern Atlantic Ocean. The Food and Agriculture Organization (FAO) estimates that more than 70% of the world's fish species are either depleted or fully exploited.
It is estimated that up to 39 million tons of fish bycatch are killed and then dumped back into the ocean each year.
Since 1950, there has been about a 90% decrease in predatory fish populations (i.e., cod) in commercial fishing areas between the British Isles and North America.
In 2006 people consumed about 110 million tons of fish, of which 47% were contributed by aquaculture.
Early estimations for 2007 suggest that the world fishery production (excluding China) is 96 million tons, which accounts for a 7% increase in aquaculture production and a 3% increase in capture production compared to 2006.
Archaeological, historical, and paleoecological data display time lags that lasted decades to centuries between the onset of overfishing and the changes in ecological communities. These time lags occurred because underfished populations assumed the ecological roles of the overfished populations until they too became overfished or died due to epidemic conditions caused by overcrowding.
Research has been conducted to evaluate overfishing, and it is suggested that the total catch per capita is about two times that estimated to ensure fishing at sustainable levels. These results illustrate the increasing trend on unsustainable fisheries and expansion of overfishing between the 1950s and the present.
Fish farming: Fish farming is the farming of species in cages or net pens that are anchored to the bottom on the ocean, typically in coastal waters. Farm-raised fish have now become a source of food and a potential conservation technique for species that are threatened by extinction.
Currently, the following species are on the endangered species list: Atlantic salmon, shortnose sturgeon, smalltooth sawfish, killer whale, Indus River dolphin, and totoaba. Several others are listed as threatened: Chinook salmon, chum salmon, coho salmon, green sturgeon, gulf sturgeon, apache trout, and steelhead trout.
The cages for offshore farming are typically more secure than net pens used for salmon farming, but both are unable to prevent fish eggs from escaping.
Escaped farmed fish may lead to ecological damage due to reduced fitness of wild fish that interbreed with the escaped farmed fish. Farmed fish are bred for quantity, not necessarily quality. Although the farmed fish may be larger and more aggressive, they may not be fit for the wild since the traits they carry on are those needed for survival on the farm. When they interbreed with wild fish, the gene pool changes and gene flow may cause the wild fish populations to lose crucial survival genes.
About one-third of the fish caught globally are used to produce fish meal and oil for farm-raised fish. A significant proportion of this catch has been used in fish farming as of late since aquaculture production continues to grow.
Water pollution is one consequence of the feeds used in farming. Much of the nutrients used in the feeds may end up in animal wastes.
Blast fishing: The explosions caused by blast fishing disrupt established communities and food webs. They may also damage the reef, creating craters and breaking the coral reef calcium carbonate structure into rubble, leading to a diminished ability to serve as a habitat and causing local extinction of the coral species. Blasted reefs may only support few fish species of lower biomass and require a long time to recover because they are slow-growing and the disturbance is chronic.
In many coastal villages, blast fishing is a tradition and a possible way to compete with commercial fishers. With little regulations on commercial fishing and large economic profit, blast fishers continue to use this technique,
Blast fishing continues because of resource depletion and the increasing poverty found in many coastal areas. It is difficult to control blast fishing in areas such as Tanzania and the Philippines because law enforcers are harassed or injured when enforcing the law, while other law enforcers protect blast fishers.
Cyanide fishing: The concentrated cyanide solution used in cyanide fishing is able to stun target and nontarget organisms. This practice is also capable of destroying coral reefs, including those whose structure is still intact. It damages these habitats by stressing the symbiotic algae (zooxanthellae) that live within the coral polyps. The loss of algae from the polyps results in discoloration, also known as "bleaching," which may be fatal to the coral. The coral reefs experience further damage when fishermen hammer the reefs in order to retrieve fish that escape deeper into the crevices in an attempt to avoid the cyanide solution.
This practice has been an issue in the Philippines since the 1960s and continues to pose a problem for Cambodia, Indonesia, Thailand, Vietnam, and the Maldives. Very few countries have regulations on cyanide fishing; however, the Philippines have established the International Marinelife Alliance (IMA) and the Bureau of Fisheries and Aquatic Resources (BFAR) to detect cyanide fishing and deter the use of this method.
Bottom trawling: Bottom trawling reduces habitat complexity and causes changes in sediment, which may cause shifts in species and declines in certain populations. For instance, organisms may be buried, along with their food supply. This process may clog the filters of sponges or lead to disintegration when pressure waves are generated by trawl gear.
The damaging effects of bottom trawling has been well-documented in areas all over the world, including the coral reefs off east Florida, the coral grounds off Nova Scotia, the reefs in Scandinavian waters, the seamounts near New Zealand and Australia, and the coral gardens in the Alaskan waters. Photographs have documented trawl scars that were 2.5 miles in length.
Bottom trawling has lead to endangered black and red corals off the coast of Australia. Off the southern coast of Australia, trawlers reportedly brought up about 1.6 tons of coral per hour in 1997.
With such large-scale damage, bans have been implemented to protect marine life and habitats. In March 2005, the United States banned bottom trawling off its west coast. Bans have also been placed in the Mediterranean, and 25% of the high seas are now protected from bottom trawling after a decision made by the nations in the South Pacific.
Abandoned gear/ghost nets: Abandoned fishing gear continues to cause adverse effects to the world's ocean and fish populations. It has been estimated that nearly 30% of marine litter may be attributed to the fishing industry, and hundreds of thousands of tons of fishing nets cover the ocean floor.
Physical damage, including destruction and smothering of coral reefs, caused by anchors and weights has been witnessed in West Ireland and the United Kingdom. Lost gill nets continue to become entangled on coral and catch fish.
According to the U.S. Environmental Protection Agency (EPA), millions of fish, seabirds, sea turtles, and various marine mammals are entangled in debris or ingest plastics that are mistaken as food.
Nearly 30,000 northern fur seals become entangled in abandoned nets and then drown or suffocate.
Lost lobster traps continue to catch lobsters and other marine life that are never properly harvested or sold.
Gear retrieval programs differ in terms of their scope and duration, resulting in a varying cost of implementation. It was estimated that a retrieval program in the Baltic Sea cost Sweden about $70,000, while Norway's cost was roughly $260,000. In 2003, a Hawaiian program spent about $10,000 per day for two chartered boats to retrieve 120 tons of net. These programs are often associated with large costs, but continued implementation may result in fewer adverse effects for marine life and the environment.
Genetic impact: Fishing affects genetic resources on a variety of levels, including genetic change, species extinction, and disruptions to ecosystems. Species extinction, along with threatened and endangered species, are most commonly found in freshwater environments and may be largely associated with degradation and habitat loss rather than fishing itself. Species that have low reproductive rates, low population sizes, and a larger size at the onset of sexual maturity, however, may be significantly affected by fishing. For example, sharks reproduce at a low rate since they mature slowly. Antarctic fish, including the benthic Antarctic cod, the marbled rock cod, and the mackerel icefish, as well as deep-sea fishes such as black cod, also become sexually mature late in life, resulting in low reproductive rates.
Measures are in place to reduce the mortality and genetic impact on fish populations. New initiatives are needed to protect the illegal harvesting of specific species and the overfishing of certain populations, which accounts for most genetic problems.
Future research involving the potential genetic impact of farm-raised fish escapes is needed.
General: The International Food Information Council (IFIC) describes health benefits of seafood, including omega-3 fatty acids, which are found in oily fish such as salmon, sardines, and tuna. Omega-3 fatty acids are thought to provide beneficial effects to the heart, brain, and immune system by reducing the risk of irregular heart rhythms, decreasing cholesterol levels, decreasing the rate of growth of cholesterol plaques, and lowering blood pressure.
Some evidence suggests that docosahexaenoic acid (DHA), a specific omega-3 fatty acid, may be beneficial for the brain development of infants. Therefore, pregnant women, nursing mothers, and women of childbearing age are encouraged to consume fish as a source of DHA. The American Heart Association (AHA) recommends eating fish that are rich in omega-3 fatty acids at least two times a week, and the American Dietetic Association (ADA) recommends eating 2-3 fish-containing meals a week. However, because fish may contain methylmercury, young children and pregnant and breast-feeding women should not exceed the recommended amounts.
According to the IFIC, a three-ounce serving of most fish and shellfish provides 20 grams of low-fat protein. Fish provide high-quality protein that is abundant with essential amino acids and minerals.
Methylmercury: Mercury is a naturally occurring substance that is also released into the air by industrial pollution. Mercury may accumulate in water bodies and transform in methylmercury, which fish who feed in mercury-polluted waters may absorb. Nearly all fish and shellfish contain a trace amount of mercury, but certain species contain more than others. Anchovies, oysters, shrimp, squid, and tilapia contain the least amount of mercury (less than 0.09 parts per million), while swordfish, tuna, and mackerel contain the highest amount of mercury (more than 0.5 parts per million) and should be consumed in moderation.
Excessive amounts of the methylmercury found in fish may damage developing nervous systems. Exposure to mercury may be particular dangerous for pregnant women and young children. If a pregnant mother or an infant ingests excessive mercury, the fetus has an increased risk of deafness and blindness, intellectual disability, and cerebral palsy. Low doses may result in a delay in speech, a shortened attention span, and learning disabilities.
The U.S. Food and Drug Administration (FDA), along with the U.S. Environmental Protection Agency (EPA), recommend that pregnant women, women who may be pregnant, nursing mothers, and children avoid specific predatory species such as king mackerel, shark, swordfish, and tilefish, all of which contain the most mercury. The EPA also recommends that these specific populations limit their weekly fish consumption to 12 ounces of fish and shellfish that are low in mercury. Such fish include catfish, canned tuna, polluck, salmon, and shrimp.
The FDA has published a list that contains the mercury levels found in various commercial fish and shellfish.
The EPA issues fish advisories when unsafe levels of various contaminants are found in fish and waters.
In August 2009, the South Carolina Department of Health and Environmental Control (SC DHEC) distributed advisories in South Carolina, warning that fish from portions of the Savanna River downstream from Augusta, Georgia, have the highest levels of mercury. The Environmental Protection Division (EPD) of Georgia also distributed similar warnings.
Cyanide: The cyanide solution used in cyanide fishing poses a health risk for fishermen. Cyanide poisoning may lead to oxygen deprivation, leading to a loss of consciousness. If exposed to large-enough doses, death may occur, while low doses are associated with temporary or permanent disabilities. Additionally, diving may result in injuries and even death. Skin bends (mottling of the skin) and embolisms are also common among divers. Proper equipment is often lacking, increasing the risk of injury and death.
Diseased species: Parasitic worms (trematodes) have caused massive infections in various farm-raised fish, including catfish.
Infectious salmon anemia (ISA) was detected in Atlantic salmon farms. ISA is an infectious disease that has a large economical impact. After the first outbreak of ISA in Norway in 1984, this virus infected the North American and European salmon farming industry. The disease is associated with anorexia, anemia, lethargy, and mortality.
A study published in the Journal of Alzheimer's Disease proposed that farm-raised fish may transmit a variant of Creutzfeldt-Jakob disease, a disease related to mad cow disease. Both Creutzfeldt-Jakob disease and mad cow disease belong to a family of diseases known as transmissible spongiform encephalopathies, which are characterized by a rapidly progressive dementia. The theory of disease transmission applies to fish that are fed by-products from infected cows. The researchers urged regulations to ban feeding bone meal or cow meat to fish until the safety of this practice has been confirmed.
Salmonella is the most common contaminant of seafood and seafood products, according to research conducted by the Economic Research Service of the U.S. Department of Agriculture (USDA ERS). Most of the Salmonella-related violations were found in shrimp and prawns, both farm-raised and wild-caught. This contamination is likely to be associated with compromises in sanitation, leading to cross-contamination during the processing phase.
Poisoning: Fugu fish contain tetrodotoxin, a lethal neurotoxin that is 1,200 times more lethal than cyanide. Ingestion of this toxin leads to death in about 60% of the people who ingest it. Symptoms of toxicity include tingling of the tongue and mouth, vomiting, dizziness, convulsions, low blood pressure, slow heart rate, fixed dilated pupils, and paralysis. Toxicity may eventually lead to death (secondary to respiratory muscle paralysis). There is no antidote to this poisoning.
Other: Different countries use different antibiotics, feed additives, and vaccines for farm-raised fish. Global regulations do not exist, but agencies such as the FDA monitor the use of such chemicals.
Swimmers and divers have become entangled in abandoned fishing lines and nets similar to marine animals.
Abandoned fishing equipment may also affect recreational and fishing boats by interfering with propellers and valves.
The FDA has refused imported shipments of shellfish and fish from China due to the presence of additive and residues, along with improper labeling. Although less frequently cited compared to handling and manufacturing infringements, the FDA has reported harmful pathogens and pesticide residues, likely related to a potentially harmful drug introduced at fish farms.
According to the GAIN Report - IT6021, published by the USDA Foreign Agricultural Service (FAS), numerous criminal offenses were reported by the Italian Coast Guard, the most common being the mislabeling of certain species of fish along with the mislabeling of previously frozen products as fresh.
FUTURE RESEARCH OR APPLICATIONS
Fish farming: Researchers have addressed the future of fishing and fish farming, expressing that the depletion of many marine fisheries poses complication, and the need to expand production through fish farming.
The global mean trophic level of fish caught has substantially declined since humans consume larger, predatory fish.
Commercial fishing has contributed to the removal of 90% of large fish such as cod, marlin, sharks, and swordfish, and 40% of the fish humans consume directly originates from commercial farms. Therefore, some suggest that fish farming may take the place of wild fisheries.
Some proponents of aquaculture suggest that farm-raised fish may replace wild-caught fish or reduce the volume of wild-caught fish.
Although farm-raised fishing practices are continuously growing, regulations are still needed. In 2003, the Pew Oceans Commission released recommendations and stopped the expansion of marine farms until national guidelines, along with proper authority, are developed regarding the design and operation of aquaculture productions.
Recovering damaged reefs: Blast fishing has damaged coral reefs throughout the world, creating rubble fields with limited coral cover and diminished fish communities.
Researchers have investigated the use of rocks and plastic mesh to replicate coral reefs to stimulate recovery of fish and coral populations. This rehabilitated environment established a low-cost method favoring the recovery process. Other studies have shown that human intervention may be feasible on a small scale, but effective management and law enforcement is needed to prevent future blast fishing.
Research suggests that clove oil may be used as an alternative to cyanide in the live fish industry. Cyanide has detrimental effects to the marine environment, whereas clove oil may prove to be an appropriate substitute for the capture, handling, and transport of live fish. The active ingredient in clove oil is suggested to be eugenol (4-Allyl-2-methoxyphenol). Clove oil induces a rapid and calm anesthesia that requires a longer recovery time compared to other anesthetics. It is also an inexpensive alternative to cyanide.
Conservation of coral reefs and species: Overfishing and destructive fishing practices have caused shifts away from coral reefs. Nearly 20% of the world's reefs have been lost, and about 26% are threatened.
Research has suggested that conservation objectives may be achieved by implementing gear modifications, catch restrictions, and closed areas. Such management tactics may provide benefit in some areas, but the lack of alternatives to fishing and the impact of the international fishing industry suggest a global initiative.
Marine protected areas (MPAs) have been created to protect coral reefs. Having MPAs provides regulation of illegal fishing and the establishment of no-fishing zones.
Organizations: Protected reefs, when properly managed, have stimulated regeneration of coral reefs and marine resources. Many local communities and national organizations support coral reef conservation, and zoning of the oceans into underfished marine reserves has been suggested.
The U.S. National Oceanic and Atmospheric Administration (NOAA) has worked to develop offshore aquaculture to preserve species that are near extinction.
The U.S. Coral Reef Task Force is a task force consisting of territorial, state, and federal representatives who meet regularly to coordinate and improve the conservation of U.S. coral reefs. Many local action strategies have been set forth as a part of this national effort.
The U.S. Coral Reef Task Force was established when President Clinton issued the Executive Order 13089 on Coral Reef Protection as a part of the National Ocean Conference, a meeting of ocean policy makers. This executive order instructs federal agencies to participate in the protection of the coral reef ecosystems and directs certain agencies to coordinate plans to restore reefs and investigate current and future threats on U.S and global reefs. Threats to coral reefs, besides overfishing and destructive fishing methods, include ocean acidification, ocean warming and coral bleaching, carbon dioxide, water pollution, coastal development, sedimentation, coral mining, and tourism.
The Department of Land and Natural Resources has also developed various action plans to address threats including overfishing and the lack of general awareness to threats to reefs and species.
The National Marine Fisheries Service (NMFS) has set numerous motions into action, including measures to end overfishing in areas such as the Hawaii Archipelago. Through various hearings, in response to amendments to the National Environmental Policy Act of 1969 (NEPA), overfished species have been identified and regulations have been proposed.
The Agricultural Research Service conducts research to investigate marine health; marine genetics; early development and reproduction; nutrition; systems for improved, sustainable, and environmentally conscious productions; and the quality and safety of aquaculture consumer products.
Researchers have suggested that the use of more grain in fish feed, rather than the typical fish meal from saltwater species, would prevent overfishing of certain saltwater species.
The USDA Foreign Agricultural Service, in an attempt to conserve shark populations, has addressed shark finning and has adopted regulations that aim to restrict or prevent the future development of the shark finning practices and prohibit the removal of shark fins.
According to the GAIN Report - IT6021, published by the USDA Foreign Agricultural Service, global initiatives have been established to deter illegal fishing practices. For example, the Italian Coast Guard seized 800 kilometers of net, 250 tons of illegal fishing products, and 3,000 pieces of illegal equipment during the 30,000 boat inspections and 166,000 market and landing point inspections conducted in 2005.
Aquarium groups have begun to fight cyanide fishing. The cyanide detection test (CDT) is able to combat cyanide fishing. It was developed in 1991 and has been used in the Philippines by law enforcement officers since 1992. Officers randomly collect samples from local buyers, exporters, and fishers and then take them to a CDT lab for testing. Stricter implementation of regulations regarding cyanide fishing may be needed to decrease this activity.
This information has been edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).
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