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Thousands of years of fishing and hunting have provided the very basis for settlement along the Norwegian coast. With the introduction of efficient vessels and gear in the 20th century, catches have increased dramatically, making it imperative to secure the economic basis of the coastal populations through an active and responsible management policy based on research and monitoring of the resources of the sea. Today, the fish stocks which are most important for Norwegian fisheries are showing a positive development, and species like Norwegian-Arctic cod and Norwegian spring-spawning herring are on the increase. It seems natural to attribute this development to a foresighted management policy, based on advice from Norwegian marine scientists and the International Council for Exploration of the Sea.
Norwegian scientists have been working on the exploration and mapping of marine resources for more than a century. Today, modern vessels and sophisticated instruments are used in a round-the-year monitoring of the sea's resources and the marine environment. The resulting knowledge constitutes the basis for regulating catches in Norwegian waters.
The goal of Norwegian resource management is to obtain a balance between catches and stock renewal, i.e. a sustainable harvesting of the ocean's resources in their entirety. Marine scientists call this "sustainable yield". A great deal of research is carried out on the subject of continuous monitoring of the marine environment, stock renewal, nutrition, growth, geographical distribution, population etc. The various stocks of fish and marine mammals must also be studied in a comprehensive ecological perspective, taking into account the interaction between the different species.
For management purposes the diet of the various fish and mammals is examined and the results entered onto so-called multi-species models. Norway has made considerable progress in this field, and the aim is to include all the major species in multi-species models which encompass the entire food chain of the ocean, from plankton to whales and seals. For the models to be complete they must also include reliable information on the quantities caught by man.
The results of the management-related research conducted by Norway's marine research institutes are summed up in stock estimates based on data concerning the numbers and age distribution of each stock together with information on factors influencing stock renewal, growth and mortality. Geographical distribution and changes in patterns of distribution are also important data in the assessment of the stocks of the various fish and marine mammals. These data are collected by the institutes' own research vessels, rented fishing craft and research vessels from other countries which Norway collaborates with in monitoring the resources of the North Sea, the Norwegian Sea and the Barents Sea.
A crucial factor when estimating the development of several important fish species is information on catches. However, catch statistics are far from reliable in several of the countries which harvest from the large, common stocks in northern waters, both with respect to quantities reported and as regards information on where the catches were made. The least reliable catch figures are for cod, haddock and other demersal fish. In order to reduce the uncertainty caused by insuffient statistics it is an important task for Norwegian marine biologists to measure stock sizes directly during their annual research expeditions.
The UNCED conference in Rio de Janeiro in 1992 introduced the term "responsible fishing" to designate sustainable exploitation of marine resources without negative impact on the environment. Subsidiary catches of species one wishes to protect should be avoided, as should the taking of fry and young fish. Thus, fishing and hunting should be selective while stocks are harvested in a manner that will ensure stock renewal and maximum long-term yield.
Norwegians have already devoted years of effort to the study of fish behaviour and catch technology, precisely in order to harvest marine resources in a rational and responsible manner. One result of these efforts is the use of sorting grids which are mounted on trawling equipment. The grids prevent the fry from entering the trawl by gently deflecting them, so that they can reach adult size before being caught. Grids have been developed for fine-meshed shrimp trawls and for fish trawls. Trials conducted with cameras mounted on the gear have confirmed that the grids function well, and studies of deflected fry show that they are not damaged. Before the introduction of sorting grids, the only way to avoid subsidiary catches was to close off areas with high concentrations of smaller fish or to prohibit certain types of gear.
From 1 January 1993 both Norway and Russia have started using sorting grids in shrimp trawls in northern waters. Norwegian and Russian researchers have conducted joint trials of an effective sorting grid for commercial cod trawlers, and successful experiments have been carried out with sorting grids on other types of equipment, such as purse seine and Danish seine.
In addition to grid development, different mesh shapes have been tested as a means of preventing unwanted subsidiary catches. The results obtained so far are encouraging.
Multi-species management implies a total assessment of interaction between the different stocks. In order to manage stocks such as capelin in the Barents Sea it is important to know how much capelin is eaten by cod. Related questions are: how much does the cod ingest of the plentiful young herring stock in the Barents Sea, and how much fish of various stocks end up in the stomachs of marine mammals?
As a tool in the quest for answers to such questions the Institute of Marine Research in Bergen has developed a multi-species model. The cod being one of the main predators of the Svalbard area and Barents Sea ecosystem, the first step has been to find out what and how much the cod eats. Such knowledge is obtained by analyzing the cod's stomach contents. Norwegian and Russian scientists have been cooperating on the taking of such samples since 1987, and today the data bases of the Institute of Marine Research in Bergen and of PINRO, the corresponding institution in Murmansk, hold information on the stomach contents of more than 50,000 cod.
The collected samples reveal a diet that varies according to size, season and area, and of course according to what prey the sea can offer. We know now that smaller cod mostly feed on crustaceans, whereas larger cod prefer capelin, which in years of plenty constitute up to 50% of the cod's intake. Big cod also include Norway haddock, shrimp, herring and smaller cod on their menu.
The cod's total consumption is calculated using a model which compares data on stomach contents with information on how fast the cod's varied diet passes through the stomach at different water temperatures.
A cod consumes from 2.5 to 3.5 times its own weight per year. Thus, a cod population of two million tonnes will need around 6 million tonnes of food annually.
Knowledge about the interaction between species is currently being put to use by scientists when recommending catch limits for capelin fisheries. Based on the analysis of stomach contents of cod it is possible to predict how much capelin the cod are likely to eat, and this mortality rate is taken into account when evaluating the development of the capelin stock. The results of the multi-species research programme have so far not been applied in management of the cod stock, as reliable data on factors such as growth dating back to the 1970s are not yet available.
Among marine mammals the most important species to incorporate into the multi-species models are the harp seal and the minke whale.
In order to learn more about the role played by marine mammals in the ecosystem a comprehensive, 5-year research programme was launched in 1989. The programme included, inter alia, mapping of stocks, collection of data concerning their food intake, health and reproductive capacity, the influence of pollution and tagging of certain species.
Public attention has been mainly focused on the minke whale hunting which took place as part of this programme. A main objective of this hunt was to learn more about the whale's diet, and how the availability of food influences its migrations and distribution. Findings indicate that smaller organisms like plankton and krill constitute a far smaller share of the menu than was generally supposed, the diet consisting mainly of fish like cod, herring and capelin.
The results confirm that marine mammals play an important part in the total ecosystem. Increased knowledge about these animals is therefore crucial for the development of a comprehensive resource management model.
The development of operative multi-species models for comprehensive marine resource management represents a pioneering effort in world science.
Norwegian spring-spawning (Atlanto-Scandic) herring has always been the most important fish stock in the Northeastern parts of the Atlantic. As the main consumer of plankton, it constitutes a central link between plankton production and higher species of the ecosystem. A large and robust herring stock is vital for secuing a stable and high yield from other marine resources in the area.
The size of the herring stock, like that of all other fish stocks, has always fluctuated in step with nature's own cycles. In the early 1950s stocks were abundant and herring fisheries along the coast had a heyday. As a result of a low renewal rate and overfishing the herring stock was severely depleted towards the end of the following decade.
Thanks to a restrictive regulation policy including several years of total prohibition of herring fishing, the herring stock is now increasing satisfactorily. By 1994 the stock of herring fry had grown to 2.5 million tonnes of spawning stock, which is considered a minimum for securing continued renewal. The Norwegian authorities plan to continue low-level harvesting, with the intention of rebuilding the spawning stock to its 1950s level of 8 to 10 million tonnes.
The Norwegian-Arctic cod stock was seriously reduced towards the end of the 1980s, due partly to a low renewal rate caused by cold sea temperatures and partly to overfishing. A big, international fishing fleet had been reducing the stock gradually since the 1950s, and the spawning stock was seriously depleted during the 1960s. At the same time, neither scientists nor the authorities had sufficient knowledge to implement regulations to prevent this deterioration. From a total of 4-6 million tonnes in the 1950s the cod stock fell to around one million tonnes. The early 1980s saw the introduction of regulatory measures, firstly for the trawler fleet, and later for the coastal fishing craft too.
As a result of these measures, a high renewal rate and healthy individual growth, the cod stock is today growing fast.
The ocean climate strongly influences biological production. Norwegian scientists have been monitoring the climate of the sea since 1936 in order to learn how climatic changes influence fish resources through the various links of the food chain. It has been established that climatic fluctuations influence growth and stock renewal, but the causes are still unclear.
More knowledge and better understanding of these processes will give man a better basis for long-term management of marine resources. The aim is to provide reliable forecasts of climatic changes and hence of biological production in the sea. This should make it possible to moderate the large annual fluctuations of fish stocks through strategic management of the resources.
For resource management purposes, insight into the primary production of the ocean is also important. Plankton makes up the first link in the food chain. Therefore, knowledge of the ocean's "grass" production is vital for estimating fish stock developments.
Finally, monitoring of marine pollution yields important information about factors that influence marine production and about the ways in which various pollutants affect marine organisms and the entire marine environment. Continuous monitoring of releases of toxic substances, oil, nutrients and organic matter is important. The surge of public interest in radioactive contamination in recent years has made it necessary to intensify research in this field. Norway and Russia are now cooperating closely in mapping radioactive pollution in the Barents and Kara Seas.
The foundations for management of marine resources are laid through comprehensive and thorough charting of all factors affecting marine production. Norwegian marine research goes back more than one hundred years, and the accumulated knowledge and experience offer a solid basis for achieving sustainable exploitation of the ocean's resources for the benefit of mankind.
Norway cannot, however, achieve this alone. Several of the most commercially important stocks are managed together with other nations. One example is Norwegian-Arctic cod, which is managed jointly with Russia.
For research the main forum for international cooperation is the International Council for the Exploration of the Sea (ICES). In addition to this, Norwegian and Russian scientists collaborate in surveying common stocks and monitoring the marine environment.
Research on the minke whale is conducted in close cooperation with the Scientific Committee of the International Whaling Commission (IWC). With the aim of coordinating research on marine mammals at a regional level, Norway, Iceland, Greenland and the Faeroe Islands established the North Atlantic Committee on Cooperation on Research on Marine Mammals (NACCRMM) in 1990.
In order to achieve sustainable use of marine resources all fishing and hunting nations should follow recommendations based on scientific study. Cooperation is also necessary between nations which harvest the same resources. Norway has cooperation agreements with, inter alia, Russia and the EU, agreements which form the basis for annual total catch quotas and distribute these among the countries that harvest the resources of the North Sea, the Norwegian Sea and the Barents Sea. Monitoring mechanisms have been set up to ensure compliance with these agreements. In this respect, the principal means of control at the disposal of Norwegian authorities are compulsory reporting of all fishing within Norway's economic zone, random checks by the Coast Guard and controls when unloading catches.
The IWC has been assigned a key role within international cooperation for the regulation of whaling. In recent years, however, the majority of its member states have been striving for the organization to become an instrument for pure preservation of whales in spite of the fact that the express purpose of the International Convention for the Regulation of Whaling, which forms the basis of the Commission's activity, is to regulate whaling in such a way as to safeguard the interests of the consumers of whale products. Norway is working actively in order to make the Commission resume its primary task of whale stock management.
In 1992 the members of the NACCRMM agreed to establish a North Atlantic Marine Mammals Commission, NAMMCO, for the regional management of whales and seals. So far, the Commission has not been assigned the task of managing minke whales and other great whale species, since these are included in the mandate of the IWC, but the NAMMCO agreement makes it possible for the organization to undertake this task as well.