Аренда офисов в Мурманске



Harald Gjosaeter
Institute of Marine Research, P. O. Box 1870 Nordnes,
N0-5817 Bergen, Norway

IUU fishing

Illegal, Unregulated and Unreported (IUU) fishing is known to take place on many fish stocks in the North Atlantic. There are several types of fishing that could be listed under the term IUU: in some cases the caught fish is not landed, but are thrown overboard for various reasons, for instance because it is a "wrong" species or it is undersized. In other cases the fish is landed illegally, "hidden" as another species, or withheld from control and account of quotas by other means. In the Barents Sea, IUU fishing of cod, haddock and other commercial stocks by transshipment of catches at sea and illegal transport to harbours without control of landings has been a particular problem in recent years. The International Council for the Exploration of the Seas has estimated the magnitude of unreported cod in the order of 25-35% of total allowable catch based on reports from bodies controlling vessels at sea, satellite tracking of fishing and transport vessels, and harbour control where the fish is landed.

Biological consequences

Among the most serious consequences are biological effects on the stock in question. The IUU fishing comes on top of all legal catches. This extra exploitation on top of a rational, regulated fishery may reduce the growth potential and the reproductive potential of the stock, and ultimately endanger the stock itself. Overfishing is normally categorised as either growth overfishing or recruitment overfishing. Growth overfishing is the least serious type of overfishing, and will affect the growth potential of the fishes in the stock in question. A fish will grow during its whole life, but the main growth phase occurs before the fish gets sexually mature. After first spawning the growth normally slows down. To get most out of a fish stock it is, therefore, necessary to wait until each individual fish has passed this rapid growth phase before it is fished. This can be accomplished through technical regulations like minimum mesh size regulations, closed areas where the young fish are mainly found etc. But the harder a stock is fished, the earlier each fish is likely to be caught. Overexploiting a stock will, consequently, reduce the mean age of fish caught and will reduce the potential yield. A stock of cod-fish will typically have a maximum yield when about 20% of the adult fish is caught each year.

Recruitment overfishing takes place when a stock is so heavily exploited that too few fish are allowed to spawn to secure a constant replenishment of the stock by new recruits. A stock in this situation will dwindle not only because it is heavily fished and are not allowed to exploit its natural growth potential, but because recruitment will fail due to lack of spawners.

There are other biological effects of overfishing, which are not easily put into quantitative terms, for instance possible negative effects when the age distribution in the spawning stock is skewed towards first-time spawners. This may reduce the population fecundity and the quality of the eggs, and lead to reduced reproductive potential per tonne of spawning fish.

Societal consequences

A societal effect of IUU fishing is that the fishermen fishing legally will get less fish than they othervice would. The are allowed to take the agreed quotas, but these will be smaller and smaller as the stock is reduced. While higher prises are normally obtained when less fish is caught and marketed, this will not necessarily be the case when an IUU fishing is going on, because the illegally caught fish is entering into the world marked and tend to keep the prices low, despite deficit in legally caught fish.

Another, less obvious, affect of IUU fishing is that it renders the scientific analysis of the stock more uncertain. Since it is normally impossible to estimate directly the size of a stock of bottom fish, and since most analytic tools for fish stock assessment therefore relies heavily on reported numbers caught of each age group present in the stock, errors in the catch statistics will weaken the quality of the assessment. It the amount of fish removed illegally is not possible to estimate in a reliable way, the uncertainty in assessment and prognoses will deteriorate, and might in the long run invalidate the scientific advice for a rational management of the stock.

In addition to the fish, the fishermen and the marine scientists, the managers will also be negatively affected by IUU fishing. They will have to consider a fish stock that is steadily decreasing despite their effort to manage it according to advice and to precautionary principles and good practice, while the advice they receive from marine scientists gets more and more uncertain and biased. If more than one nation is involved, IUU fishing might also directly affect the share each nation gets from a common resource.

These factors will be discussed during this talk, and though the perspective is general, reference will be made to the situation with cod fishery in the Barents Sea.



Добавить комментарий

Защитный код

Язык сайта:

English Danish Finnish Norwegian Russian Swedish

Популярное на сайте

Ваш IP адрес:

Последние комментарии

При использовании материалов - активная ссылка на сайт https://helion-ltd.ru/ обязательна
All Rights Reserved 2008 - 2017 https://helion-ltd.ru/

@Mail.ru Яндекс.Метрика
Designed by Helion LTD