Fish stocks are subpopulations of a particular species of fish, for which intrinsic parameters (growth, recruitment, mortality and fishing mortality) are traditionally regarded as the significant factors determining the stock's population dynamics, while extrinsic factors (immigration and emigration) are traditionally ignored. Stocks fished within biologically sustainable levels decreased from 90% in 1974 to 62.3% in 2021. [1]
All species have geographic limits to their distribution, which are determined by their tolerance to environmental conditions, and their ability to compete successfully with other species. In marine environments this may be less evident than on land because there are fewer topographical boundaries, however, discontinuities still exist, produced for example by mesoscale and sub-mesoscale circulations that minimize long-distance dispersal of fish larvae.
For fish, it is rare for an individual to reproduce randomly with all other individuals of that species within its biological range. There is a tendency to form a structured series of discrete populations which have a degree of reproductive isolation from each other in space, in time, or in both. This isolation is reflected in the development between sub-populations of genetic differences, morphological variations and exposure to different chemical regimes and parasitic species. Sub-populations also respond to fishing in such a way that fishing on one population appears to have no effect on the population dynamics of a neighbouring population.
The currently accepted definition of a stock in fisheries science, is that of Begg et al. (1999), “…[a “stock”] describes characteristics of semi-discrete groups of fish with some definable attributes which are of interest to fishery managers.”
Stock identification is a field of fisheries science which aims to identify these subpopulations, based on a number of techniques.This concept is applied in sustainable development goal 14 where target 14.4 is measured a fish stock sustainability indicator 14.4.1. [2]
The United Nations defines straddling stocks as "stocks of fish such as pollock, which migrate between, or occur in both, the economic exclusion zones (EEZ) of one or more states and the high seas". [3] Sovereign responsibility must be worked out in collaboration with neighbouring coastal states and fishing entities. Usually this is done through the medium of an intergovernmental regional organisation set up for the purpose of coordinating the management of that stock.
Straddling stocks are usually pelagic, rather than demersal. Demersal species move less than pelagic species, since they tend to relate to bottom topography. Pelagic species are more mobile, their movements influenced by ocean temperatures and the availability of zooplankton as food. Example pelagic fish are capelin, herring, whiting, mackerel and redfish, There are, however, a few demersal species that are straddling, such as the Greenland halibut migrates in feeding/spawning migrations to Greenland in the west and to the Faeroes in the east. [4]
Straddling stock can be compared with transboundary stock. Straddling stock range both within an EEZ as well as in the high seas. Transboundary stock range in the EEZs of at least two countries. A stock can be both transboundary and straddling. [5]
In fisheries science and ecology, stock assessment is an important tool in fisheries management.
In particular, to ensure continued, healthy, fish stocks, measurements of the Spawning Stock Biomass (the stock population capable of reproducing) allows sensible conservation strategies to be developed and maintained through the application of sustainable fishing quotas. [6]
The World Wildlife Fund and the Zoological Society of London jointly issued their "Living Blue Planet Report" on 16 September 2015 which states that there was a dramatic fall of 74% in world-wide stocks of the important scombridae fish such as mackerel, tuna and bonitos between 1970 and 2010, and the global overall "population sizes of mammals, birds, reptiles, amphibians and fish fell by half on average in just 40 years." [7] It is hoped that global efforts like the United Nations Sustainable Development Goal 14 meets its targets aimed at reversing these trends. [8]
The UN Food and Agriculure Organization found that stocks fished within biologically sustainable levels decreased from 90% in 1974 to 62.3% in 2021.. [9]
The stocks for individual marine species can "boom and bust" in linked and compensatory ways. For example, in billfish longline fisheries, the Atlantic catch of blue marlin declined in the 1960s. This was accompanied by an increase in sailfish catch. The sailfish catch then declined from the end of the 1970s to the end of the 1980s, compensated by an increase in swordfish catch. As a result, the overall billfish catch remained fairly stable. At Georges Bank, a decline in cod during the 1960s was accompanied by a rise in flatfish, and more recently, with the collapse of the predatory Atlantic cod, lobster catches in Maine have boomed. [10]
This article incorporates text from a free content work.Licensed under CC BY-SA 3.0 IGO( license statement/permission ).Text taken from In brief, The State of World Fisheries and Aquaculture, 2018 ,FAO,FAO.
Fishing is the activity of trying to catch fish. Fish are often caught as wildlife from the natural environment, but may also be caught from stocked bodies of water such as ponds, canals, park wetlands and reservoirs. Fishing techniques include trawling, longlining, jigging, hand-gathering, spearing, netting, angling, shooting and trapping, as well as more destructive and often illegal techniques such as electrocution, blasting and poisoning.
Fishery can mean either the enterprise of raising or harvesting fish and other aquatic life or, more commonly, the site where such enterprise takes place. Commercial fisheries include wild fisheries and fish farms, both in freshwater waterbodies and the oceans. About 500 million people worldwide are economically dependent on fisheries. 171 million tonnes of fish were produced in 2016, but overfishing is an increasing problem, causing declines in some populations.
An aquatic animal is any animal, whether vertebrate or invertebrate, that lives in bodies of water for all or most of its lifetime. Aquatic animals generally conduct gas exchange in water by extracting dissolved oxygen via specialised respiratory organs called gills, through the skin or across enteral mucosae, although some are evolved from terrestrial ancestors that re-adapted to aquatic environments, in which case they actually use lungs to breathe air and are essentially holding their breath when living in water. Some species of gastropod mollusc, such as the eastern emerald sea slug, are even capable of kleptoplastic photosynthesis via endosymbiosis with ingested yellow-green algae.
Overfishing is the removal of a species of fish from a body of water at a rate greater than that the species can replenish its population naturally, resulting in the species becoming increasingly underpopulated in that area. Overfishing can occur in water bodies of any sizes, such as ponds, wetlands, rivers, lakes or oceans, and can result in resource depletion, reduced biological growth rates and low biomass levels. Sustained overfishing can lead to critical depensation, where the fish population is no longer able to sustain itself. Some forms of overfishing, such as the overfishing of sharks, has led to the upset of entire marine ecosystems. Types of overfishing include growth overfishing, recruitment overfishing, and ecosystem overfishing. Overfishing not only causes negative impacts on biodiversity and ecosystem functioning, but also reduces fish production, which subsequently leads to negative social and economic consequences.
The fishing industry includes any industry or activity that takes, cultures, processes, preserves, stores, transports, markets or sells fish or fish products. It is defined by the Food and Agriculture Organization as including recreational, subsistence and commercial fishing, as well as the related harvesting, processing, and marketing sectors. The commercial activity is aimed at the delivery of fish and other seafood products for human consumption or as input factors in other industrial processes. The livelihood of over 500 million people in developing countries depends directly or indirectly on fisheries and aquaculture.
The billfish are a group of saltwater predatory fish characterised by prominent pointed bills (rostra), and by their large size; some are longer than 4 m (13 ft). Extant billfish include sailfish and marlin, which make up the family Istiophoridae; and swordfish, sole member of the family Xiphiidae. They are often apex predators which feed on a wide variety of smaller fish, crustaceans and cephalopods. These two families are sometimes classified as belonging to the order Istiophoriformes, a group which originated around 71 million years ago in the Late Cretaceous, with the two families diverging around 15 million years ago in the Late Miocene. However, they are also classified as being closely related to the mackerels and tuna within the suborder Scombroidei of the order Perciformes. However, the 5th edition of the Fishes of the World does recognise the Istiophoriformes as a valid order, albeit including the Sphyraenidae, the barracudas.
A regional fishery body (RFB) is a type of international organization that is part of an international fishery agreement or arrangement to cooperate on the sustainable use and conservation of marine living resources and/or the development of marine capture fisheries whose such capacity has been recognized by the UN Food and Agriculture Organization under the United Nations Fish Stocks Agreement.
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.
The blue whiting one of the two species in the genus Micromesistius in the family Gadidae, which also contains cod, haddock, whiting, and pollock. It is common in the northeast Atlantic Ocean from Morocco to Iceland and Spitsbergen. It also occurs in the northern parts of the Mediterranean, where it may be locally abundant. Blue whiting also occur in the northwest Atlantic Ocean between Canada and Greenland, but is considered rare. It has a long, narrow body and a silvery underbody. The fish can attain a length of more than 40 cm. The average length of blue whiting caught off the west shores of the UK is 31 cm.
This is a glossary of terms used in fisheries, fisheries management and fisheries science.
As with other countries, the 200 nautical miles (370 km) exclusive economic zone (EEZ) off the coast of the United States gives its fishing industry special fishing rights. It covers 11.4 million square kilometres, which is the second largest zone in the world, exceeding the land area of the United States.
The coastline of the Russian Federation is the fourth longest in the world after the coastlines of Canada, Greenland, and Indonesia. The Russian fishing industry has an exclusive economic zone (EEZ) of 7.6 million km2 including access to twelve seas in three oceans, together with the landlocked Caspian Sea and more than two million rivers.
The fishing industry in the Maldives is the island's second main industry. According to national tradition in the words of former President Maumoon Abdul Gayoom, "Fishing is the lifeblood of our nation, it is inborn. From the soil on which we live, to the sea around us, it remains an integral part of our existence. Fishing, and our country and its people, [are] one and shall remain inseparable forever." The Maldives has an abundance of aquatic life and species of fish. Common are tuna, groupers, dolphin fish, barracuda, rainbow runner, trevally and squirrelfish and many more. Aside from being of essential importance to the economy, fishing is also a popular recreational activity in the Maldives, not only among locals but by tourists. The islands have numerous fishing resorts which cater for these activities.
The fishing industry plays a significant part in the national economy of Pakistan. With a coastline of about 1,120 km, Pakistan has enough fishery resources that remain to be developed. Most of the population of the coastal areas of Sindh and Balochistan depends on fisheries for livelihood. It is also a major source of export earning.
The Chilean jack mackerel, sometimes called the Jurel, Inca scad or Peruvian jack mackerel, is a species of jack mackerel in the genus Trachurus of the family Carangidae. Since the 1970s, it has become one of the world's more important commercial fish species. High volumes have been harvested, but the fishery may now be in danger of collapsing.
The Cape horse mackerel is a mackerel-like species in the family Carangidae. It is a pelagic species of the south eastern Atlantic Ocean which is a target of fisheries, mainly as bycatch.
The following outline is provided as an overview of and topical guide to fisheries:
Fishing is important to the national economy of Vanuatu. It is the main source of income for many in the islands and Vanuatu's biggest export. According to 2009 figures, approximately 77% of households in Vanuatu are involved in fishing activity. According to 2005 figures, Vanuatu caught 151,080 fish in that year, with frozen fish accounted for half of Vanuatu's commodity exports.
The fishing industry in Denmark operates around the coastline, from western Jutland to Bornholm. While the overall contribution of the fisheries sector to the country's economy is only about 0.5 percent, Denmark is ranked fifth in the world in exports of fish and fish products. Approximately 20,000 Danish people are employed in fishing, aquaculture, and related industries.
Of the twelve species of billfish, there are six species of Billfish in the Indian Ocean.