Marine fisheries – the state of affairs
Exploitation on a massive scaleTotal global production of fish and fishery products from capture fisheries and aquaculture currently stands at around 140 million tonnes per annum. Until the early 1990s, the harvest from marine fishing followed an almost constant upward trajectory, with landings worldwide increasing fourfold from an annual figure below 20 million tonnes in 1950 to around 80 million tonnes in 1990. Since the 1990s, the total amount of fish, shellfish and crab caught in the sea has remained more or less constant.
Due to the great demand for fishery products, fish farming is also steadily expanding, especially in Asian countries. With an annual growth of around 7 per cent, aquacultureaquacultureis one of the most rapidly expanding food industry sectors. Aquaculture already provides more than 40 per cent of the global consumption of fish and shellfish. However, many fish species raised in the aquaculture sector are predatory fish, which rely on a supply of other fish for food. Wild-caught fish are therefore used as feed. Although the amounts vary considerably according to species, it takes an average of around 5 kilograms of fish meal and fish oil to produce 1 kilogram of farmed fish.Further information on this topic is available here:
Wild-caught fish are also used as breeding stock. Switching to consumption of farmed fish alone, therefore, does not necessarily protect wild fish stocks.
The expansion of marine fishing has contributed significantly to the decline and in some cases the depletion of global fish stocks.the decline and in some cases the depletion of global fish stocks.Overexploitation particularly affects long-lived fish species such as redfish (Sebastes marinus) which take several years to reach maturity and begin spawning. In extreme cases, it may even lead to the depletion of the stock. For example, stocks of cod in the Northwest Atlantic off the United States coast have collapsed after years of overfishing.Further information on this topic is available here:
- 6.1 > The example of North Sea cod shows how a fish stock collapses (i.e. becomes depleted) if there are no longer enough mature fish (spawning stock, green) available to produce offspring.
- 6.2 > Aquaculture is a booming industry today and fish are being farmed on a large scale, as seen here on the Chinese island of Hainan. However, fish farms do not necessarily help to conserve wild fish stocks as they require large quantities of fish meal or wild-caught forage fish for feed.
Decline of spawning stockNorth Sea cod stocks, too, have been greatly reduced by intensive fishing. This species is a particularly good example of the effects of the exploitation of the seas. Experts define a stockstockas a self-sustaining population of a fishspecies within a geographically defined area. The spawning stock – i.e. the mature individuals that are capable of reproduction – are particularly important in scientific terms. The Food and Agriculture Organization of the United Nations (FAO) does not provide any precise definitions of the various status categories of stocks. For example, the boundary between “fully exploited” and “overexploited” status is somewhat fuzzy. According to the FAO, the term “fully exploited” means that a fishery is operating at or close to an optimal yield level, with no expected room for further expansion. A stock is termed “overexploited”Further information on this topic is available here:“overexploited”if it is being exploited above a level that is believed to be sustainable in the long term, evident from the steady decline of the stock. A stock is said to be depleted if catches are well below historical levels, irrespective of the amount of fishing effort exerted. A stock is said to be recovering if catches are again increasing after having been depleted.Further information on this topic is available here:
According to FAO estimates,According to FAO estimates,there has been a steady increase in the proportion of overexploited and depleted stocks since the 1970s. By contrast, there has been a decrease of around 50 per cent in the proportion of underexploited stocks, which stood at an estimated 20 per cent in 2006. This trend may be due to the development of increasingly efficient fishing technology, including technically improved means to locate shoals of fish and ever more powerful fishing vessels. The construction of enormous factory ships means that large catches can be frozen while the vessel is still at sea, enabling ships to exploit fishing grounds at great distances from the port of landing. Continuing advances in fishing technology also allow fish to be caught at ever greater depths. Furthermore, due to a lack of alternatives, commercial fishing is increasingly turning to species that were previously regarded as unprofitable, of poor quality, or unfit for consumption.Further information on this topic is available here:
6.5 > Catches and landing values by groups of species
6.4 > World marine capture fisheries production since 1950
Stock assessment – a difficult taskCorrectly assessing fish stocksassessing fish stocksis a difficult task. As it is not possible to count fish individually, stock sizes are now estimated using mathematical models. Current catch figures from the fishing industry are an important source of data in this endeavor. The models also take account of the effort that must be employed in order to catch this quantity of fish, based, for example, on the number of fishing days or the fleet size – for the fewer the fish there are in the sea, the greater the effort needed to achieve a specific catch volume. However, even today not all catches are reported, so the available data may be incomplete.Further information on this topic is available here:available data may be incomplete.The mathematical models therefore also include information from scientific test catches, which are regularly carried out by fisheries biologists and include data on the age structure of the fish stocks and stock density. Measured in terms of total catch weight, the People’s Republic of China tops the list of the world’s leading fishing nations by a clear margin; China claims to land an estimated 14 million tonnes of fish or more annually. In second place is Peru, with an annual catch weight of around 7 million tonnes. In regional terms, the Northwest Pacific (19.8 million tonnes) and the Southeast Pacific (11.8 million tonnes) are the fishing areas yielding the largest catches.Further information on this topic is available here:
With annual production of 7 to 10 million tonnes, the Peruvian anchoveta is the most productive marine species. It is a mainstay of the Peruvian fishing industry and is also caught by other countries. Second in the ranking is Alaska pollock (Theragra chalcogramma) (2.9 million tonnes), followed by Atlantic herring (Clupea harengus) (2.4 million tonnes).
Generating billions in revenue – with fish meal and gourmet filletsThe estimated landed value of fish globally is around USD 90 billion. Even more added value is generated in the processing industry, which turns the fresh catch into a variety of fishery products. The commercial value of different fish species varies considerably, firstly due to the different amounts available on the world markets and, secondly, because various fish species enjoy different levels of popularity among consumers. Rare species of tuna can command prices in excess of 100 euros per kilogram on the Asian market,Rare species of tuna can command prices in excess of 100 euros per kilogram on the Asian market,whereas fishermen are paid as little as 10 to 20 cent for a kilo of sprats.Further information on this topic is available here:
The prices of fishery products also depend on how the catches are processed. Broken down by quantity, the various forms of utilization of world fisheries production have remained more or less constant over recent years. Around three-quarters of the catch is destined for direct human consumption, with approximately half of this reaching the final consumer in the form of fresh fish, a quarter being processed into frozen food products, and a further quarter being preserved by curing, pickling or canning before being brought to market. The remaining 23 per cent of the catch is processed into fish meal and fish oil, mainly for the feedstuffs industry, and is used in aquaculture and poultry farming, for example. The significance of fish in terms of its contribution to the human diet also varies from region to region.The significance of fish in terms of its contribution to the human diet also varies from region to region.Consumption of fishery products is heavily dependent on the availability of other food sources and proximity to the sea. Worldwide, approximately 16.4 kilograms of fishery products (live weight) per capita per year (average for 2003 to 2005) are used for consumption. This figure includes products from inland fisheries and aquaculture. However, per capita consumption in the European Union countries (EU-15) is 25.7 kilograms – well above this average. Compared with countries such as Spain (42.6 kilograms) and Portugal (55.4 kilograms), where fish has traditionally formed a major part of the diet, per capita consumption of fishery products in Germany is 14.3 kilograms, and hence broadly in line with the global average.Further information on this topic is available here:
Fishing and aquaculture provide employment for an estimated 43.5 million people worldwide, mostly in Asian and African countries. The People’s Republic of China accounts for the major share, with more than 12 million people employed in fishing and aquaculture.