With almost a third of its waters with some type of protection, the European coasts should be a paradise for fish. However, in a strange paradox of conservation, a study with data from thousands of boats shows that more fishing is done in most marine protected areas (MPAs) than outside them. The research also reveals that many species without commercial interest are disappearing from these areas.
All boats with a length of 15 meters or more must have an automatic identification system installed (AIS, for its acronym in English). Every few seconds, each ship emits not only its identification, but its position, route, speed … With this information and an artificial intelligence system, a group of researchers was able to identify thousands of fishing boats. The same artificial neural network, by means of the use of trained algorithms, could determine the art of fishing of each boat thanks to that their movements are different depending on the fishing gear. The researchers were interested in bottom trawling, the most industrial of all the arts and one of the most extractive and indiscriminate.
The job, published in Science, detected 2,689 trawlers that fished in European waters in 2017. The study does not include the Mediterranean. In total, all that fleet was fishing just over a million hours. But the most striking thing is that a quarter of that time, they fished within the limits of one of the 727 protected areas they studied. The investigation revealed that in 59% of these areas there is trawling. Moreover, in relative terms, more is fished within these areas than outside.
The AIS system allows to know the position, speed or route of the boats every few seconds
Analyzing the movements of the ships, the artificial intelligence system was able to determine if the boats were fishing or not. The presence of trawlers (in hours per square kilometer) throughout the entire MPA network was 38% higher within them compared to non-protected areas. But it is that, considering only the time in which the networks were at the bottom of the sea, the percentage of extra time goes up to 46%.
In a second part of the study, the researchers looked for a possible relationship between this intensity of trawling in the protected areas and the abundance of fish. They focused on a score of elasmobranch species, such as sharks, rays and blankets. Most of them have no commercial interest, so they are caught incidentally and discarded. Its situation could serve as an indicator of the situation of marine biodiversity as a whole.
Here they turned to the database of the International Council for the Exploration of the Sea (CIEM), an intergovernmental organization that, through scientific expeditions, studies the situation of fishery resources and the whole of marine life. Although there is only information on the ICES scientific catches of elasmobranchs from 178 of the marine protected areas, the researchers found that the relative abundance of sharks, rays and rays was 24% higher than inside. Some species in danger of extinction, such as a pair of dog shark species or the Norwegian skate, are hardly found within MPAs even though they are. However, the study also reveals that the total population of elasmobranchs (both inside and outside of MPAs) has been increasing for at least a decade.
"Although we have shown that the intensity of trawling is a good predictor of the abundance of elasmobranchs (more intense, less elasmobranchs), it may not be the same with species with more commercial interest, such as small bony fish" , says the main author of the study, the researcher of Dalhousie University (Halifax, Canada), Manuel Dureuil. "However, these MPAs are not effectively protecting biodiversity and are in conflict with the guidelines of the International Union for the Conservation of Nature (IUCN), which state that any fishing gear used in MPAs must demonstrate that they have a significant impact on other species, "adds the German biologist, also president of ShARCC, an organization that studies Atlantic sharks.
The problem is that the protection of marine life is not the same as that of life on land. "There are not many land areas where you can kill lions as it is allowed to kill sharks in the sea," recalls the director of the global marine and polar program of the IUCN, the Swedish Carl Gustaf Lundin. Although this organization has developed a classification with six categories or degrees with the conditions that should be met by marine protected areas, its compliance is neither binding nor is it as advanced as terrestrial.
Regarding the study, in which he has not participated, Lundin, recalls that trawling nets are one of the less selective fishing gears. "It's like if you pull all the tree species to get the wood of a species," he compares. But remember that "many of these MPAs do not prevent fishing activity." A good part of the problem is that, even though there is enough science, the decisions do not follow only the scientific logic. We must also consider the political interests and those of the fishing sector.
"There are not many land areas where you can kill lions as it is allowed to kill sharks in the sea"
Carl Gustaf Lundin. Director of the global marine and polar program of the IUCN
"There is a certain disconnect between policies to conserve biodiversity and the sustainable exploitation of resources," says Paul Fernandes, professor of fisheries science at the University of Aberdeen (United Kingdom). At the community level, "the Framework Directive on the Marine Strategy (DMEM) tries to address this to some extent, but the fact is that the Common Fisheries Policy (PPC) operates largely independently of the DMEM, "explains this expert in fishery resources management.In practice, fisheries and biodiversity protection have separate paths.
Fernandes also agrees with the authors of the study that marine protected areas, by themselves, "are ineffective in protecting larger and more mobile marine species, such as elasmobranchs." However, remember, your populations in Europe are increasing. To a large extent, this relative improvement would have been due to the implementation of recovery plans based on the reduction of fishing pressure. But, for this professor, if you really want to save sharks, rays or blankets there are only two ways: reduce discards with more selective fishing and, in particular, end the demand: "We should concentrate our efforts in reducing , when not eliminate, the markets of the Far East for shark fin ".