The biological and environmental effects of fishing
Published: 13/07/2010Fishing is a widespread and pervasive form of maritime activity, which has expanded very rapidly over the last 70 years. With the help of new and ever more effective technology, very few places are out of reach.
Contents:
1. Overfishing
A fish stock is said the be overfished when more fish is caught than can be replaced through natural reproduction. Today, 75 per cent of global fish stocks are fully exploited or overfished. Fishing vessels in the North Sea, for example, remove between 60 and 75 per cent of all cod each year – a figure that is clearly unsustainable.
By removing a large amount of fish from a population, its size and the number of individuals it consists of are reduced. This is exacerbated by the fact that most of the large fish are removed early on, and fishermen then begin catching young fish that have not yet reproduced. This causes the population to decrease even quicker. Eventually, when too many fish have been removed, a stock may plunge into commercial extinction, as happened with the once immensely rich cod stocks on the Canadian Grand Banks in the 1980s. The North Sea cod is close to the same fate, with only 20 per cent of the estimates of mature individuals in the 1980s left.
Overfishing also leads to so-called knock-on effects. In some species, for example, older females lay many more eggs than younger ones. In cod, a five year-old female lays as many eggs as 37 one-year-old females. Another example is the removal of large predatory species, such as tuna, swordfish and sharks, which may lead to a boom in their prey species, in turn leading to a shift in the ecological balance. There is a trend today to ”fish down the food web” – as fisheries for large predators become depleted and fishers turn to exploiting species further down on the food chain, causing them to decrease too. If this trend continues, scientists warn that it could lead to a widespread fisheries collapse with disastrous consequences for marine biodiversity.
Inadequate fisheries management both at national and international level has allowed overfishing to become a serious problem, with fleet overcapacity and badly targeted subsidies as two of the main drivers.
Contents:
2. Overcapacity
The main culprit in the fisheries crisis is the overcapacity of the global fishing fleet. There are simply too many boats chasing a dwindling number of fish. Sonar fish finders, hydraulic gear, stronger engines, spotter planes and satellite communication systems have all made it possible to chase up every single shoal in the sea. So, although fish is becoming scarcer, fishermen are getting better at finding and catching the remaining ones. This, of course, puts a tremendous pressure on fish stocks around the world.
Today, global fishing capacity is more than 250 per cent above a sustainable level. This overcapacity is, in turn, exacerbated by the ongoing technological development increasing the efficiency of fishing vessels, so that they can catch more fish in a shorter time. The power of a 2004 trawler, for example, is several times that of one built in the 1970s. This expansion of the global fleet has to a large extent been supported by state subsidies.
Efforts to reduce the number of vessels, in order to decrease the fishing pressure, have mostly been undermined by technological advances.
Contents:
- Overfishing
- Overcapacity
- The EU debate on Rights-Based Management tools in fisheries
4. The EU debate on Rights-Based Management tools in fisheries
Rights-Based Management includes any system of allocating individual fishing rights to fishermen, fishing vessels, enterprises, cooperatives or fishing communities. Such systems, which exist in all fisheries management regimes in one form or another, basically define the rights to use fisheries resources. Fishing rights have a value and can be traded. The trade in fishing rights was first addressed in the context of the 2002 reform of the Common Fisheries Policy, when the Commission committed itself to producing a report on the scope for provisions within EU and/or national fisheries management systems for a system of tradable fishing rights, which can be individual or collective.
In February 2007, the Commission adopted a communication on Rights-Based Management tools in fisheries, which found that markets in fishing rights exist in most Member States. In some, national regimes specify that days at sea or part of the catch quota can be sold or leased. In others, those who wish to acquire more fishing rights have to buy a fishing vessel. The degree of transparency or openness of these transactions may vary greatly depending on how the system is formalised. Even when they are not specified by national law, in most Member States such markets exist de facto.