Every year, around 3,000 tonnes of waste are dumped in the Mediterranean, and around 10% are lost or abandoned fishing gears in seafloors. The effect caused by these fishing tools –the phenomenon of ghost fishing– is yet another threat to the biodiversity of marine ecosystems, which are currently seriously threatened by pollution, climate change, fishing, invasive species and diver frequentation, among other factors.
In this context, the most recent campaign of the project “Evitem la pesca fantasma” (stop ghost fishing) carried out about 34 extraction operations over the last year, and took 32 fishing tools –a surface over 1,900 square meters– which were abandoned in the seafloors of the Catalan coasts. This project, which focuses on the preservation of a natural heritage, conducted, since 2009, a total of 66 extractions in the Catalan coasts, which meant recovering 150 fishing tools. Under the scientific supervision of Bernat Hereu, lecturer at the Faculty of Biology and member of the Biodiversity Research Institute (UB-IRBio) of the University of Barcelona, the initiative counted on the support of the Directorate-General of Fisheries and Maritime Affairs of the Catalan Government.
Abandoned nets that trap the marine life
Abandoned fishing gears in seafloors are a deadly trap for biodiversity. “This is a common phenomenon in the coast which causes a constant and recurring fishing effect on marine life. This ghost fishing catch can take weeks —even years— and can also affect protected species, such as red coral”, notes Hereu, from the UB Department of Evolutionary Biology, Ecology and Environmental Sciences.
Trammel nets, seine nets, traps, longlines and lines were the main recovered fishing tools from the seabeds during the last campaign, which began in October 2019. The marine habitats formed by sand, rock and coralline were the most affected by this environmental problem, and the most severe consequences were reported in the communities of molluscs, algae, arthropods, porifera, bryozoans and cnidarians.
The passive capture of organisms that die entangled in fishing gears is not the only effect of fishing tools on marine habitats. They also erode ocean floors, drown biological communities, introduce pollutants into the environment, and can be vectors for invasive species. At the same time, they generate economic losses for the fishing sector –the lost material must be replaced– and are a potential risk for the safety of vessels, maritime traffic and users of aquatic activities.
Scientists, fishermen and managers with the same objective
In 2018, the first protocol prepared in Catalonia was presented to remove the nets and fishing gears –sports and artisanal– that were stuck in the rocks of the seafloors. This protocol, supervised by lecturer Bernat Hereu, is coordinated by Joan Ylla, head of the Service for Marine Control and Action of the Directorate-General for Fisheries and Maritime Affairs of the Catalan Government.
“Evitem la pesca fantasma” (stop ghost fishing) enabled the consolidation and improvement of the mentioned action protocol with several actors and participating entities, and to characterize the amount and type of lost fishing gears in the Catalan coasts. Once the warning about the presence –for instance– of a casted net in seafloors is published, researchers identify the exact location through a remotely operated vehicle (ROV). With the support of graphic material, they work on a first diagnosis of the net (state of conservation, level of coats by organisms, etc.) which will allow them to take decisions.
Safe extraction operations are carried out by professional divers –in the last two campaigns, by the companies Deltasub and Mésdemarunder– the management of the Directorate-General of Fisheries of the Catalan Government, the underwater units of the Mossos (Catalan police force) and rural agents, and the scientific advice of the UB-IRBio experts. After separating the nets from the substrate, they are tied with cable ties to balloons that they fill with air so that they float to the surface. Once on land, the scientific team documents the presence of organisms in the recovered tools to assess their environmental impact.
This fight against the impact of lost fishing gears in the marine environment has counted on the collaboration of fishermen’s associations –especially many artisanal fishermen who have actively collaborated in the detection and extraction of lost fishing gears–as well as diving centers and entities such as the Catalan Federation of Underwater Activities (FECDAS).
“In this project, the coordinated work between scientists, fishermen, local agents and the Administration (forest agents, police forces, professional divers) is essential to be able to minimize the impact of lost fishing gears in our coasts”, comments researcher Julia Ortega ( UB-IRBio).
In 2020, “Evitem la pesca fantasma” counts on the support of the Biodiversity Foundation (Ministry for Ecological Transition and Ministry of Agriculture and Fisheries, Food and Environment), through the Pleamar program of the European Maritime and Fisheries Fund (FEMP). Among the most immediate challenges for the future, the project wants to improve the process of detecting abandoned arts and its social involvement, in addition to creating a public database –updated and georeferenced–on lost fishing gears and maximizing awareness of the citizens regarding a serious environmental problem that affects marine biodiversity.