Overfishing

Untangling the fishing nets

We need to face the facts: the great blue ocean is not the inexhaustible source of wealth we once thought it to be. And the good image of the fishing profession has slowly become tamished with the over-exploitation of the sea’s resources. Scientists and fishermen are at loggerheads, the former warning us of the catastrophic impacts of overfishing, the latter defending their livelihoods. What everyone does seem to agree on is the need to conserve fish stocks in the long term. But how? Scientific research does not yet have all the answers. And politicians need to take into account the answers that already exist.

Bluefin tuna fishing  at Favignana (Sicily – IT) This overexploited nomad species  undertakes major migrations in the north Atlantic  and adjacent seas, from its feeding grounds in colder regions to its spawning  grounds in warmer climates. © Ifremer/Olivier Barbaroux Bluefin tuna fishing at Favignana (Sicily – IT) This overexploited nomad species undertakes major migrations in the north Atlantic and adjacent seas, from its feeding grounds in colder regions to its spawning grounds in warmer climates. © Ifremer/Olivier Barbaroux
Miraculous catch of  fish? Industrial fishing  centred on a single species, the orange roughy (New Zealand sea perch). © Australian Fisheries  Management Authority Miraculous catch of fish? Industrial fishing centred on a single species, the orange roughy (New Zealand sea perch). © Australian Fisheries Management Authority
20% of shark species  are in the process of becoming extinct, mainly because of juveniles being caught in nets not intended  for them. One of the latest winners of the Smart Gear competition for  innovations to support sustainable fishing organised by the WWF has devised a  system of magnets to keep them away from trawlers-longliners fishing for tuna  and swordfish. © WWF-Canon/Jason Rubens 20% of shark species are in the process of becoming extinct, mainly because of juveniles being caught in nets not intended for them. One of the latest winners of the Smart Gear competition for innovations to support sustainable fishing organised by the WWF has devised a system of magnets to keep them away from trawlers-longliners fishing for tuna and swordfish. © WWF-Canon/Jason Rubens
The Caretta tortoise, a protected species in the Bay of Laganas,  at Zakinthos (Ionian Islands – GR). © WWF-Canon / Michel Gunther The Caretta tortoise, a protected species in the Bay of Laganas, at Zakinthos (Ionian Islands – GR). © WWF-Canon / Michel Gunther

Has Europe squandered its marine resources? After 25 years of the Common Fisheries Policy (CFP), the situation is increasingly a cause for alarm. FAO(1) reports on the state of the world’s fish stocks show that the percentage of permanently fished species has been constantly falling, from 40 % in 1974 to just 23 % in 2005. And the Union is directly concerned. The north-east Atlantic, from where over twothirds of Europe's fish catches come, is one of the zones in which biodiversity is most under threat (2). Here 46 % of all stocks are overfished, impoverished or recovering, compared to 25% of fish stocks worldwide. The CFP “has not delivered sustainable use of fisheries resources and will need to be changed if it is to do so. Its shortcomings can be expressed in conservation, political and economic terms,” as stated back in 2001 in the Commission’s Green Paper on the future of the CFP.

At last, an ambitious reform…

Politicians’ difficulty in reconciling economic and ecological imperatives is one of the main reasons for this failure. 76 % of infringement proceedings against Member States in the CFP area relate to overfishing. The CFP has been applied with a very soft hand. Launched in 1982, it has certainly helped avoid conflicts at sea between national interests, but has at best papered over the cracks when it comes to overfishing. Some will talk of the iron grip of economics, others will blame politicians seeking electoral capital; whatever the reason, politicians have rarely succeeded in imposing fishing quotas in line with the total admissible catches (TAC) which are scientifically defined to ensure the renewal of fish populations. Certain subsidies have also aimed at gradually reducing the fleet whilst modernising the remaining vessels. Laudable but ineffective: the reduction in boat numbers has been offset by the growing catch capacity of individual vessels. We know today that ocean biodiversity is based on a complex tissue of synergies between various marine organisms, the survival of which depends on the fragile balance regulating their environments. This complexity was only partly understood when the CFP was set up. For this reason the CFP still assesses the state of fish resources by the sole indicators of population and fishing-induced mortality, stock by stock, independently of the evolution of the ecosystems. The ultimate aim of the CFP, in its revised (2002) format, is to provide a basis for the sustainable exploitation of marine resources. But this calls for more research, because our knowledge of the ‘ocean system’ is still too limited to effectively introduce the new ‘ecosystemic’ approach the Commission has adopted.

Counting the uncountable… with errors?

“We are working to assess a resource of which it is impossible to count the individual components one by one. We are therefore forced to gauge the state of fish populations indirectly, with the help of statistical models,” Pierre Petitgas explains. This biologist and geostatistician from Ifremer coordinates Fisboat, a European project which is seeking to perfect ways of assessing marine resources. The current process is based on a combination of data from sampling undertaken by scientists at sea, and of catch declarations. The biases of sea sampling can be calculated and corrected, but it is impossible to determine to what extent fishermen report the true numbers of catches and rejects. It is therefore imperative to increase the reliability of evaluation methods, based both on scientific samples and the flow of declarations from the fishing profession. “The quantification of uncertainties is part and parcel of scientific recommendations. It is a sine qua non for embedding the precautionary approach into the political decision-making process,” Ifremer stresses.

Another mistake is to base political decisions on partial data. “Looking only at the demographic indicators is tantamount to producing a partial diagnosis of the real situation. It’s like a farmer who examines only one corner of his cornfield without checking that the entire crop is growing at a normal pace,” is how Pierre Petitgas describes it. It is this which probably cost Canada the collapse of its cod stocks before declaring a moratorium in 1992. At the time, several biological indicators that scientists were measuring – mortality rates, age of sexual maturity, spatial distribution of the population – had not been included in the reports presented to politicians. Subsequent examination has shown, however, that indicators of the deterioration of the stocks existed well before civil society was informed of them. Europe’s marine industries need, therefore, more reliable and predictive assessments. This is the role of Fisboat, the evaluation methods of which will be tested in ICES (3).

Smart Gear: rethinking fishing technologies

Another major challenge is to develop fishing technologies that are less damaging to the marine environment. This is no mean challenge, given the impressive number of non-target organisms that are caught up accidentally in fishing nets. From 3.8% for the least destructive fishing technologies to 50% for certain vessels, such as bottom trawlers, which also cause inestimable damage to highly fragile marine habitats like coldwater corals. Oceanographers and nature conservation organisations are crying out ever louder against such fishing techniques, the exact consequences of which on the benthic ecosystem, where damage is particularly slow to recover, is still poorly determined.

But we still have to propose other options to fishermen. Since 2005, WWF has organised SmartGear, an international competition open to brains from all horizons, professionals, engineers, teachers and students. The objective is to promote ways of fishing that reconcile respect for the environment with commercial viability. The most innovative solutions are at times disconcertingly simplistic. The 2006 winner was an invention which can limit the impact of fishing on sharks, 20% of the species of which are on the verge of extinction. The idea? To use sharks’ aversion to intense magnetic fields and their unique capacity to detect them. Powerful magnets, placed above the long-line baits used by tuna and swordfish fishermen, scare them away from the deadly long-lines.

The third prize the same year went to a Danish invention which reduces captures of juveniles and little non-targeted fish by reinventing the non-return net placed at the codend(4). With the help of little flexible tubes threaded onto the cord, the net presents a ‘variable geometry’ mesh which retains only large fish, letting the small ones pass through unharmed. This more flexible, easier and less dangerous to handle system has been widely adopted by the blue whiting fisherman of the Faeroes since the coming into force, in June 2006, of a law making non-return nets obligatory.

The future: protected marine zones

These technological improvements do not, however, resolve a more fundamental problem: fishing takes away the largest fish which weigh the most and whose spawn is the most viable. This selection process favours smaller and less fertile fish, disturbs the demographic structure of the species most popular with consumers, further weakens populations that are already on the verge of extinction and reduces hopes for a restoration of marine biodiversity. For example, we are seeing a reduction in the average age of sexual maturity of cod, one heavily overexploited species, which could permanently reduce the size and reproductive capacity of the individual fish.

The ideal would be to set up ‘respite zones’ in which fish could grow to their full size. But each species does so in a very specific environment. To be really effective, given the degree of marine biodiversity, these respite zones would need to cover very large areas. But from the socio-economic viewpoint, setting up natural reserves closed to any fishing activity on such a scale is almost inconceivable, as it would sound the death knell of the fishing industry.

But there is nothing to prevent the definition of strategic zones where fishing activities are more strictly regulated in order to afford greater protection to the ecosystems. This is the concept of the marine protected area (MPA), which is one of the priorities of the 2002 CFP. But the term itself is a source of confusion, being used to designate both natural reserves that are closed to all fishing activity and the zones where fishing activity is regulated more strictly, and where the rules can vary depending on the ecosystem needing protection. This more general approach seeks also to reconcile ecological necessities and socio-economic imperatives.

But how does one demarcate and manage such areas? Which indicators does one choose to evaluate their effectiveness? These are all questions which European projects like Protect are seeking to answer, in particular by analysing earlier experiences. In a report published in February 2006, the Protect researchers took a close look at six MPAs(5) in the north Atlantic. The five European ones each had one point in common – they failed to meet their goals. This is hardly surprising: the reasons for setting them up in the first place were vaguely defined, with few predefined indicators to assess their impact. “Which is not to say that the system is ineffective. The challenge in setting up MPAs lies in understanding the complex of processes and activities in the targeted zone, and in foreseeing the long-term social and economic impacts,” explains Ole Vestergaard, a researcher at Difres (6) and the coordinator of Protect. “We are trying to develop forecasting models to permit optimal planning. This includes, for example, formulating precise management objectives and defining the information we must first have on the different interactions of the environment and human activities.”

High hopes are placed on research being undertaken to achieve an ecosystemic management of the fishing industry. Pulling this off will be particularly difficult given the incredibly diverse synergies of the marine world. It also remains to be seen how the political world will respond to these new forms of management. The experts are giving a clear message: for an MPA to succeed, it must always be supported by clear, absolutely unambiguous and rigorously applied legislation.

Julie Van Rossom

  1. Food and Agriculture Organization of the United Nations Since 1974, the FAO has published the SOFIA  reports which assess the state of fish resources worldwide.
  2. This list also includes the south-east Atlantic, the south-east Pacific and the high sea tuna fishing zones of the Pacific and Atlantic Oceans (SOFIA 2006).
  3. International Council for the Exploration of the Sea
  4. The codend is situated at the far end of the trawl.
  5. Defined here as any management measure directed at a marine zone.
  6. Danish Institute for Fisheries Research.

Top

To find out more