Fishery Management

Fisheries management

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Fisheries management draws on fisheries science in order to find ways to protect fishery resources so sustainable exploitation is possible. Modern fisheries management is often referred to as a governmental system of appropriate management rules based on defined objectives and a mix of management means to implement the rules, which are put in place by a system of monitoring control and surveillance.


The control of fisheries and fish production has been exercised in many places around the world for hundreds of years. For example, the Māori people, residents of New Zealand for about the last 700 years, had strict rules in their traditional fishing activities about not taking more than could be eaten and about throwing back the first fish caught (as an offering to Tangaroa, god of the sea).

Another longstanding example is the North Norwegian fishery off the Lofoten islands, where a law has existed for more than 200 years to control fishing activity, in this case primarily motivated by problems occurring during periods of high density of fishers and fishing gear. To avoid taking too many fish out of one specific area, gillnetters and longliners are separated and not allowed to fish in the same grounds south of Lofoten.

Governmental resource protection-based fisheries management is a relatively new idea, first developed for the North European fisheries after the first Overfishing Conference held in London in 1936. In 1957 the British fisheries researchers, Ray Beverton and Sidney Holt, published a seminal work on North Sea commercial species fisheries dynamics.[1] The work was later (in the 1960s) used as a theoretical platform for the new management schemes set up in North European countries.

After some years away from the field of fisheries management, Ray Beverton reassessed his earlier work and in a paper given at the first World Fisheries Congress in Athens in 1992, he criticised some of the concepts that he had earlier laid out in "The Dynamics of Exploited Fish Populations" and expressed concern at the way his and Sydney Holt's work has been misinterpreted and misused by so many fishery biologists and managers during the previous 30 years.[2] Nevertheless, the institutional foundation for modern fishery management had been laid.


The political goal of resource use is often a weak part of the system of fisheries management, as objectives can conflict. Typical political objectives when exploiting a fish resource are to:

  • maximise sustainable biomass yield (see maximum sustainable yield)
  • maximise sustainable economic yield (see optimum sustainable yield)
  • secure and increase employment in certain regions
  • secure protein production and food supply
  • increase income from export
  • biological and economic yield


International agreements are required in order to regulate fisheries taking place in areas outside national control. The desire for agreement on this and other maritime issues led to the three conferences on the Law of the Sea, and ultimately to the treaty known as the United Nations Convention on the Law of the Sea (UNCLOS). Concepts such as exclusive economic zones (EEZ, extending 200 nmi from the nation's coasts) allocate certain sovereign rights and responsibilities for resource management to individual countries.

There are a number of situations that need additional intergovernmental coordination. For example, in the Mediterranean Sea and other relatively narrow bodies of water, EEZ of 200 nmi are irrelevant, yet there are international waters beyond the 12 nmi line of coastal sovereignty. International agreements, therefore, must be worked out for fishery management in the international waters of the narrow sea.

There are also issues with straddling fish stocks. Straddling stocks are fish stocks that migrate through, or occur in, more than one economic exclusion zone. Here 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.

UNCLOS does not prescribe precisely how fisheries that occur solely in international waters should be managed, and there are several new fisheries (such as high seas bottom trawling fisheries) that are not yet subject to international agreement across their entire range. Both of these issues came to a head within the United Nations in 2004 and the UN General Assembly issued a resolution on Fisheries in November 2004 which set the scene for the further development of international fisheries management law.

Fisheries objectives need to be expressed in concrete management rules. The management rules today, in most countries, should be based on the internationally agreed, though non-binding, standard Code of Conduct for Responsible Fisheries, agreed at an FAO session in 1995. The precautionary approach prescribed here is also implemented in concrete management rules as minimum spawning biomass, maximum fishing mortality rates, etc. In 2005 the Fisheries Centre at the University of British Columbia comprehensively reviewed the performance of the world's major fishing nations against the Code of Conduct for Responsible Fisheries.[3]


When it comes to controlling the activities of individual fishers or fishing operations (vessels or companies), available management means can be sorted into four categories:

Taxation on input; vessel licensing Taxation on output; restrictions on catching techniques
Limited entry control Catch quota and technical regulation

The top row represents indirect methods while the bottom row represents direct methods of regulation. vessel monitoring systems, patrol vessels and aircraft, and observers aboard fishing vessels are examples of direct regulatory methods. The left column shows input controls and the right column output controls.

Many countries have set up Ministries and Government Departments, named "Ministry of Fisheries" or similar, controlling aspects of fisheries within their exclusive economic zones.

Technical regulation of fishing may include:

  • the prohibition of fishing with the use of mechanical devices such as bows and arrows, and spears, or firearms
  • the prohibition of fishing with nets, or the average potential catching power of a vessel in the fleet (taking into account the typical size, fishing gear, electronic gear and other physical "inputs", as well as the vessel's crew.[4]
  • the prohibition of fishing with bait
  • snagging of fish
  • regulation of fish traps
  • restrictions on the number of poles or lines per fisherman
  • restriction on the number of simultaneous fishing vessels
  • the average intensity of operation of a vessel per unit time at sea, measuring the fraction of the potential catching power that is actually realised
  • the average time at sea for a vessel in the fleet.


According to a 2008 UN report, titled The Sunken Billions: The Economic Justification for Fisheries Reform, the world's fishing fleets are losing $50 billion USD each year through depleted stocks and poor fisheries management. The report, produced jointly by the World Bank and the UN Food and Agriculture Organization (FAO), asserts that half the world's fishing fleet could be scrapped with no change in catch. In addition, the biomass of global fish stocks have been allowed to run down to the point where it is no longer possible to catch the amount of fish that could be caught.

"By improving governance of marine fisheries, society could capture a substantial part of this $50 billion annual economic loss. Through comprehensive reform, the fisheries sector could become a basis for economic growth and the creation of alternative livelihoods in many countries. At the same time, a nation’s natural capital in the form of fish stocks could be greatly increased and the negative impacts of the fisheries on the marine environment reduced."[5]

Type of quotaEdit

Main article: Individual transferable quota

In 2008 a large scale study of fisheries that used individual transferable quotas (ITQ) and ones that didn't provided strong evidence that ITQ's can help to prevent collapses and restore fisheries that appear to be in decline.[6][7][8][9]

Elderly maternal fishEdit

File:Sebastes mystinus 2.jpg

Traditional management practices aim to reduce the number of old, slow-growing fish, leaving more room and resources for younger, faster-growing fish. Most marine fish produce huge numbers of eggs and larvae, and the assumption has been that the younger spawners will produce plenty of viable larvae.[10]

However, recent (2005) research on rockfish shows that large, elderly females are far more important than younger fish in maintaining productive fisheries. The larvae produced by these older maternal fish grow faster, survive starvation better, and are much more likely to survive than the offspring of younger fish. Failure to account for the role of older fish in maintaining healthy populations may help explain recent collapses of some major US West Coast fisheries. Recovery of some stocks is expected to take decades. One way to prevent such collapses may be to establish marine reserves, where fishing is not allowed and fish populations age naturally.[10]

Ecosystem based fisheriesEdit

According to marine ecologist Chris Frid, the fishing industry has been keen to identify pollution and global warming as the causes of unprecedented low fish levels in recent years. But it is clear that overfishing has also altered the way the ecosystem works. "Everybody would like to see the rebuilding of fish stocks and this can only be achieved if we understand all of the influences, human and natural, on fish dynamics.” Frid adds: “Fish communities can be altered in a number of ways, for example they can decrease if particular sized individuals of a species are targeted, as this affects predator and prey dynamics. Fishing, however, is not the sole perpetrator of changes to marine life - pollution is another example [...] No one factor operates in isolation and components of the ecosystem respond differently to each individual factor."[11]

The traditional approach to fisheries science and management has been to focus on a single species. This can be contrasted with the ecosystem-based approach. Ecosystem-based fishery concepts have existed for some years and have been implemented in some regions.[12] In a recent (2007) effort to "stimulate much needed discussion" and "clarify the essential components" of ecosystem-based fisheries science, a group of scientists have offered the following ten commandments for ecosystem-based fisheries scientists[13]

  • Keep a perspective that is holistic, risk-adverse and adaptive.
  • Maintain an “old growth” structure in fish populations, since big, old and fat female fish have been shown to be the best spawners, but are also susceptible to overfishing.
  • Characterize and maintain the natural spatial structure of fish stocks, so that management boundaries match natural boundaries in the sea.
  • Monitor and maintain seafloor habitats to make sure fish have food and shelter.
  • Maintain resilient ecosystems that are able to withstand occasional shocks.
  • Identify and maintain critical food-web connections, including predators and forage species.
  • Adapt to ecosystem changes through time, both short-term and on longer cycles of decades or centuries, including global climate change.
  • Account for evolutionary changes caused by fishing, which tends to remove large, older fish.
  • Include the actions of humans and their social and economic systems in all ecological equations.

Population dynamicsEdit

Main article: Population dynamics of fisheries

Population dynamics describes the ways in which a given fishery stock grows and shrinks over time, as controlled by birth, death, and emigration or immigration. It is the basis for understanding changing fishery patterns and issues such as habitat destruction, predation and optimal harvesting rates. The population dynamics of fisheries is used by fisheries scientists to determine sustainable yields.[14][15][16]

The basic accounting relation for population dynamics is the BIDE model:[17]

N1 = N0 + BD + IE

where N1 is the number of individuals at time 1, N0 is the number of individuals at time 0, B is the number of individuals born, D the number that died, I the number that immigrated, and E the number that emigrated between time 0 and time 1. While immigration and emigration can be present in wild fisheries, they are usually not measured.

Need for quality dataEdit

According to fisheries scientist Milo Adkison (2007), the primary limitation in fisheries management decisions is the absence of quality data. Fisheries management decisions are often based on population models, but the models need quality data to be effective. Scientists and fishery managers would be better served with simpler models and improved data.[18]

The most reliable source for summary statistics is the FAO Fisheries Department.[19]


Ecopath, with Ecosim (EwE), is an ecosystem modelling software suite. It was initially a NOAA initiative led by Jeffrey Polovina, but since primarily developed at the Fisheries Centre of the University of British Columbia. In 2007, it was named as one of the ten biggest scientific breakthroughs in NOAA’s 200-year history. The citation states that Ecopath “revolutionized scientists’ ability worldwide to understand complex marine ecosystems”. Behind this lies two decades of development work in association with Villy Christensen, Carl Walters, Daniel Pauly, and other fisheries scientists, followed with the provision of user support and training. Currently there are 6000 registered users in 155 countries. Ecopath is widely used in fisheries management as a tool for modelling and visualising the complex relationships that exist in real world marine ecosystems.

Human factorsEdit

If fisheries management is to be successful, then associated human factors, such as the reactions of fishermen, are of key importance, and need to be understood.[20] As fisheries management evolved, it became increasingly clear it was really about managing people, and not about managing fish. There is little point in instructing fish to avoid nets and hooks. Fish populations are managed by regulating the actions of people. [21]

Management regulations must also consider the implications for stakeholders. Commercial fishermen rely on catches to provide for their families just as farmers rely on crops. Essentially commercial fishermen are just harvesting fish for distribution to the public. Commercial fishing can be a traditional trade passed down from generation to generation. Most commercial fishing is based in towns built around the fishing industry; regulation changes can impact an entire town’s economy. Cuts in harvest quotas can have adverse affects on the ability of fishermen to compete with the tourism industry. Increasing property values and taxes along waterfronts and properties can diminish water access.[22]

See alsoEdit








External linksEdit

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