Basic info on living resources and biodiversity

Importance of living resources to man

Maintaining marine biodiversity and marine living resources is essential to man: they provide people with food, jobs and income. In many countries of the world where the total protein intake level may be low, fish and marine product is the main source of animal proteins. Fishing and aquaculture provides direct employment, but also many indirect jobs in distribution and transformation of sea products. It is of great economical importance for many families, but also for countries that export their production. Production of sea products has steadily increased since the beginning of the century, but only aquaculture is still developing – fishing production has come to a stop with the full exploitation of the world wild stocks and the overexploitation and depletion of a majority of them.

Actual state of fisheries

Actual state of fisheries

Marine scientists, in universities, government laboratories and regional fishery commissions have recognized for the last 2 decades at least that most ocean resources (and probably all inland wild resources in populated areas) are severely depleted. Their biomass, which according to the Law of the Sea should absolutely not be reduced beyond 50% of their virgin state (and even that level is considered excessive now) are at best at 25% of the virgin level and for a number of highly valuable resources down to 10% or less. Some have collapsed.  With increasing demography and economic growth the pressure is likely to increase.

The fishing activity is widespread in all aquatic ecosystems. As a very large part of the wild resources are overfished or depleted, the impact of fishing is widespread, affecting stock reproduction to a significant degree practically everywhere.  The commercial fishing industry is now threatening the very basis of the marine food chain. In addition to direct impacts on target species, commercial fishing catch non-target species of marine wildlife including by-catch, sea turtles, seabirds, and marine mammals. Other problems are linked with aquaculture: abusive use of wild fish to feed the raised species, pollution (eutrophication, contaminants and antibiotics) and biological invasion.

The Causes

The Causes

For decades the world’s commercial fishing fleets have been taking unsustainable amounts of fish and marine

life, to the extent that many fish stocks are now declining or even collapsing. Since the early 1990s, total world catch of wild stocks have been oscillating around 85 million tonnes indicating that, under the present system, the world potential has been reached. The real figures are however blurred by statistical errors in sampling systems; biases from non-reporting (e.g. illegal fishing); under-reporting; false reporting (for political purpose); and climatic oscillations. Government subsidies and improved fishing technology at relatively low cost (GPS, cell phones…) allow commercial fishing fleets to continue expanding and adding capacity. Globally, fishing power has continued to increase during the last decade without any major change in catch, underlining the fact that fishery stress continues to increase.

Free access to resources and competition between fishers makes it difficult to maintain acceptable level of catches. The decline in fish stocks in the northern hemisphere has resulted in an exodus of large-scale, long-range industrialized fishing fleets from nations such as Japan and the Member States of the European Union (plus China, Thailand, Korea, Taiwan, former USSR and a score of convenience flags) to the relatively less exploited waters of the South and towards the deep high seas. There, the governments of many coastal states, anxious to earn hard currency to pay off foreign debts, sell the rights to fish in their waters while continuing to develop their own fleets (particularly in the period 1975-1990). Against a huge flow of financial resources from the rich North to the poor South, the result has been the demise of small-scale artisanal fishers and a drain of natural resources from the South to the North.

Other threats to fishery health worldwide include: pollution from land based sources; habitat alteration and destruction; non sustainable and destructive fishing techniques (trawling, use of poisons, etc); global climate change. In highly developed areas, the conversion of coastal habitats by a growing coastal development and the large scale pollution coming from coastal and inland industrial developments are unfortunately poorly documented in terms of their impact on the aquatic fauna (pollution by hormones, dioxins, heavy metals and hundreds of new chemicals per year for which the combined effect are unknown, but also radiations, withdrawal of river water, change in water flow regimes, etc….).

Tourism (sportfishing, diving, trade of “souvenirs” made with endangered species…), aquariology are also threats to living resources and marine biodiversity.

The effects

The effects

Because of the complexity of the ecosystem, the range of vulnerability of the various components of the resources and their state of depletion, the reconstitution of depleted wild populations is not always straightforward and may take many years and even decades for some long-lived species in highly constraining environments. Indeed in some cases, recovery may not be possible at all. Long-lived fish will be particularly difficult to rebuild. Restoring habitats can be even more difficult.  Hard bottom habitats that may be critical to such recovery may take decades or more to rebuild, limiting the recovery rates.

The consequences of drop of fisheries are multiple: economical, social and environmental like threatened food security of societies heavily dependent on fish; loss of biological resources; loss of biodiversity; health

problems; starvation and unemployment. Some reports have shown that a growing number of the fish we eat are contaminated with heavy metals like mercury, industrial pollutants like PCBs and pesticides like DDT.

Solutions and management

Solutions and management

Solutions to the over-exploitation of fish are many and varied, and operate on a number of levels. They include: ending government subsidies for unsustainable fishing practices; control of dangerous and illegal fishing technologies; reductions in the size of the global commercial fishing fleet; restrictions on certain types of gear. To be efficient all management practices should be ecosystem-based and all measures should be implemented within improved legal framework particularly in the high seas.

Equally important, however, is the need for consumers to be aware of the food they are eating and to become educated as to the possible environmental effects of its capture and consumption.

Without a major change in governance and consumption patterns, the present fishery system is simply not viable. Good examples are available, showing that these systems can be made sustainable through a mix of conservation and management measures. A Code of Conduct has been adopted. New instruments have been designed. But failing to apply and comply with them, many more fisheries will collapse in the next one or two decades and mankind may have to face a serious food security problem that will hit particularly the least endowed.

Sources and links

about living resources and biodiversity

Facts and figures

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