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The gill plate trade is the buying and selling of stingray gill plates for their use in traditional Chinese medicine. The gill plates are harvested from stingrays that are caught intentionally, or caught as bycatch. The plates are sold whole or in a powder form. A single kilogram of the gill plate can be sold for up to US$350, though the price varies by ray species. [1]
Stingrays are caught by fishing lines or nets. Private fishermen tend to target these ray species due to the high payout from their gill plates. Large fishing operations tend to catch rays as bycatch when fishing for more desirable food fish such as tuna, where they are brought back to shore and sold regardless of the intention to catch these fish. The gill plates are split in two and dried after they are taken from the dead rays. [2] Once dried the plates are sold whole or ground into a powder.
Tonics made from stingray gill plates are used in traditional Chinese medicine, [3] [4] but there is no evidence of its effectiveness in any medical treatment. [4] [5]
A few biological factors known as K-selected traits make the stingray more susceptible to population decline. These K-selected traits include, but are not limited to, late sexual maturity, long gestation, and low number of offspring. [6] [5] [4] [7] Because the gill plate trade will accept plates from both immature and mature rays, the number of rays that are able to reproduce is decreased by the capture of these animals. The population is slow to recover from these losses due to the K-selected traits and as fishing continues the population of stingrays decreases at a faster rate than it increases. [7]
The gill plate trade affects other marine species in one of two ways. The first is the impact that the fishing has on these other species which inhabit the rays ecosystem is when rays are caught intentionally they are typically caught by longline fishing. Longline fishing involves thousands of baited hooks on one very long fishing line close to the ocean's surface. [8] These hooks draw many species including birds, marine mammals, fish, sharks, and rays. The second impact of stingray fishing and population decline is an ecological effect. The stingrays are keystone predators in coral reef environments, when these species are declined the other reef species are effected through trophic factors, for instance predator populations decrease therefore prey populations increase, and risk effects. Risk effects are the behavioral mannerisms that prey learn to avoid predators, such as where or when to feed without becoming a meal for a predator. [9] Without predators such as stingrays, the behavior of prey species is altered.
It is currently illegal to trade manta and mobula ray species without proper documentation that it is sustainable trade due to these species having been added to the CITES list. [10] [11] Once a species has been added to the CITES list it is internationally protected in legal trade; however, black market transactions still occur.
Manta rays are large rays belonging to the genus Mobula. The larger species, M. birostris, reaches 7 m (23 ft) in width, while the smaller, M. alfredi, reaches 5.5 m (18 ft). Both have triangular pectoral fins, horn-shaped cephalic fins and large, forward-facing mouths. They are classified among the Myliobatiformes and are placed in the family Myliobatidae. They have the largest brains and brain to body ratio of all fish, and can pass the mirror test.
Longline fishing, or longlining, is a commercial fishing angling technique that uses a long main line with baited hooks attached at intervals via short branch lines called snoods or gangions. A snood is attached to the main line using a clip or swivel, with the hook at the other end. Longlines are classified mainly by where they are placed in the water column. This can be at the surface or at the bottom. Lines can also be set by means of an anchor, or left to drift. Hundreds or even thousands of baited hooks can hang from a single line.This can lead to many deaths of different marine species Longliners – fishing vessels rigged for longlining – commonly target swordfish, tuna, halibut, sablefish and many other species.
Bycatch, in the fishing industry, is a fish or other marine species that is caught unintentionally while fishing for specific species or sizes of wildlife. Bycatch is either the wrong species, the wrong sex, or is undersized or juveniles of the target species. The term "bycatch" is also sometimes used for untargeted catch in other forms of animal harvesting or collecting. Non-marine species that are caught but regarded as generally "undesirable" are referred to as "rough fish" and "coarse fish".
The Antarctic toothfish is a large, black or brown fish found in very cold (subzero) waters of the Southern Ocean near Antarctica. It is the largest fish in the Southern Ocean, feeding on shrimp and smaller fish, and preyed on by whales, orcas, and seals. It is caught for food and marketed as Chilean sea bass together with its sister species, the more northerly Patagonian toothfish. Often mistakenly called "Antarctic cod," the Antarctic toothfish belongs to the notothen family (Nototheniidae), a group of fish species abundant near Antarctica.
A shark net is a submerged net placed at beaches designed to intercept large marine animals including sharks, with the aim to reduce the likelihood of shark attacks on swimmers. The majority of shark nets used are gillnets which is a wall of netting that hangs in the water and captures the marine animals by entanglement, however only around 10% of catch is the intended target shark species. The nets in Queensland, Australia, are typically 186m long, set at a depth of 6m, have a mesh size of 500mm and are designed to catch sharks longer than 2m in length. The nets in New South Wales, Australia, are typically 150m long, set on the sea floor, extending approximately 6m up the water column, are designed to catch sharks longer than 2m in length. Shark nets do not create an exclusion zone between sharks and humans, and are not to be confused with shark barriers.
The yellowfin tuna is a species of tuna found in pelagic waters of tropical and subtropical oceans worldwide.
Alepisaurus ferox, the long snouted lancetfish, longnose lancetfish, or cannibal fish, is a species of lancetfish found in the ocean depths down to 1,830 m (6,000 ft). This species grows to 215 cm (85 in) in total length and a weight of 9 kg (20 lb).
The great hammerhead is the largest species of hammerhead shark, belonging to the family Sphyrnidae, attaining an average length of 4.6 m (15 ft) and reaching a maximum length of 6.1 m (20 ft). It is found in tropical and warm temperate waters worldwide, inhabiting coastal areas and the continental shelf. The great hammerhead can be distinguished from other hammerheads by the shape of its "hammer", which is wide with an almost straight front margin, and by its tall, sickle-shaped first dorsal fin. A solitary, strong-swimming apex predator, the great hammerhead feeds on a wide variety of prey ranging from crustaceans and cephalopods, to bony fish, to smaller sharks. Observations of this species in the wild suggest that the cephalofoil functions to immobilize stingrays, a favored prey. This species has a viviparous mode of reproduction, bearing litters of up to 50 pups every two years.
Drift netting is a fishing technique where nets, called drift nets, hang vertically in the water column without being anchored to the bottom. The nets are kept vertical in the water by floats attached to a rope along the top of the net and weights attached to another rope along the bottom of the net. Drift nets generally rely on the entanglement properties of loosely affixed netting. Folds of loose netting, much like a window drapery, snag on a fish's tail and fins and wrap the fish up in loose netting as it struggles to escape. However the nets can also function as gill nets if fish are captured when their gills get stuck in the net. The size of the mesh varies depending on the fish being targeted. These nets usually target schools of pelagic fish.
The devil fish or giant devil ray is a species of ray in the family Mobulidae. It is currently listed as endangered, mostly due to bycatch mortality in unrelated fisheries.
The pelagic stingray is a species of stingray in the family Dasyatidae, and the sole member of its genus. It is characterized by the wedge-like shape of its pectoral fin disc, which is much wider than long, as well as by the pointed teeth in both sexes, whip-like tail with extremely long tail spine, and uniform violet to blue-green coloration. It generally reaches 59 cm (23 in) in width. The pelagic stingray has a worldwide distribution in waters warmer than 19 °C (66 °F), and migrates seasonally to spend the summer closer to the continental shelf and at higher latitudes. The only stingray that almost exclusively inhabits the open ocean, this species is typically found in surface waters down to a depth of 100 m (330 ft). As a consequence of its midwater habits, its swimming style has evolved to feature more of a flapping motion of the pectoral fins, as opposed to the disc margin undulations used by other, bottom-dwelling stingrays.
The environmental impact of fishing includes issues such as the availability of fish, overfishing, fisheries, and fisheries management; as well as the impact of industrial fishing on other elements of the environment, such as bycatch. These issues are part of marine conservation, and are addressed in fisheries science programs. According to a 2019 FAO report, global production of fish, crustaceans, molluscs and other aquatic animals has continued to grow and reached 172.6 million tonnes in 2017, with an increase of 4.1 percent compared with 2016. There is a growing gap between the supply of fish and demand, due in part to world population growth.
A wild fishery is a natural body of water with a sizeable free-ranging fish or other aquatic animal population that can be harvested for its commercial value. Wild fisheries can be marine (saltwater) or lacustrine/riverine (freshwater), and rely heavily on the carrying capacity of the local aquatic ecosystem.
This is a glossary of terms used in fisheries, fisheries management and fisheries science.
Forage fish, also called prey fish or bait fish, are small pelagic fish which are preyed on by larger predators for food. Predators include other larger fish, seabirds and marine mammals. Typical ocean forage fish feed near the base of the food chain on plankton, often by filter feeding. They include particularly fishes of the order Clupeiformes, but also other small fish, including halfbeaks, silversides, smelt such as capelin and goldband fusiliers.
The giant oceanic manta ray, giant manta ray, or oceanic manta ray, is a species of ray in the family Mobulidae, and the largest type of ray in the world. It is circumglobal and is typically found in tropical and subtropical waters, but can also be found in temperate waters. Until 2017, the species was classified in the genus Manta, along with the smaller reef manta ray. DNA testing revealed that both species are more closely related to rays of the genus Mobula than previously thought. As a result, the giant manta was renamed as Mobula birostris to reflect the new classification.
Saltwater fish, also called marine fish or sea fish, are fish that live in seawater. Saltwater fish can swim and live alone or in a large group called a school.
Lampris guttatus, commonly known as the opah, cravo, moonfish, kingfish, and Jerusalem haddock, is a large, colorful, deep-bodied pelagic lampriform fish belonging to the family Lampridae, which comprises the genus Lampris.
The Western Pacific Regional Fishery Management Council (WPRFMC) is one of eight regional councils established under the Magnuson-Stevens Fishery Conservation and Management Act (MSA) in 1976 to manage offshore fisheries. The WPRFMC's jurisdiction includes the US exclusive economic zone (EEZ) waters around the State of Hawaii; US Territories of American Samoa and Guam; the Commonwealth of the Northern Mariana Islands (CNMI); and the US Pacific remote island areas of Johnston, Midway, Palmyra and Wake Atolls; Baker, Howland and Jarvis Islands; and Kingman Reef. This area of nearly 1.5 million square miles is the size of the continental United States and constitutes about half of the entire US EEZ. It spans both sides of the equator and both sides of the dateline. The WPRFMC also manages domestic fisheries based in the US Pacific Islands that operate on the high seas.
Worldwide, hundreds of thousands of sea turtles a year are accidentally caught in shrimp trawl nets, on longline hooks and in fishing gill-nets. Sea turtles need to reach the surface to breathe, and therefore many drown once caught. Loggerhead and hawksbill turtles are particularly vulnerable. Nearly all species of sea turtle are classified as Endangered. They are killed for their eggs, meat, skin and shells. They also face habitat destruction. Climate change has an impact on turtle nesting sites. As fishing activity expands, this threat is more of a problem.