UB experts Bernat Hereu, Cristina Linares, Pol Capdevila and Eneko Aspillaga participate in this first action to detect and remove lost fishing gear. The campaign aims at minimizing the impact that fishing stuff produces on the seabed and marine ecosystems. It will also increase natural park usersʼ awareness of the fragility of the seabed and the efforts that must be made in order to preserve and recover natural heritage.
Ghost nets that continue catching fish
Most gear used in leisure fishing —a widely practised activity which is normally compatible with the preservation of natural areas— and artisan fishing —the most sustainable fishing practice to exploit fisheries— are passive fishing arts. In other words, gear is not spread out by power-driven boats and they are not swept along the seabed. “However —says Bernat Hereu, professor in the Department of Ecology of the UB and coordinator of the scientific campaign—, when fishing gear (hooks, threads, weights, long lines, trammel, etc.) get lost or trapped on the seabed, they may produce severe impacts on marine ecosystems”.
Lost fishing gear are real “ghost nets” that continue catching fish for many months without any type of profit for fisheries. According to experts, they are responsible for a high percentage of incidental bycatch of commercial and non-commercial species all over the world. Moreover, caught fish can be a death trap for marine birds like cormorants and shags.
A threat to seabed biodiversity
Lost fishing nets, which can be hundreds of metres long, are swept along the seabed by the movement of water masses (water currents, storms, etc.), so they can become fouled with sessile organisms that inhabit marine seabed.
“Communities inhabiting the seabed —particularly coralline— are composed by a large amount of slow growing organisms which present a fragile structure, like algas calcareas, gorgonians, bryozoans, arborescent algae, etc. They are particularly sensitive to any physical alteration and they need so much time to recover”, emphasizes Bernat Hereu.
Long lines and hooks may also produce severe damages to benthos when they become fouled in sessile organisms (gorgonians, coral, algae, etc.). It is important to highlight that, as times goes by, plastic used to manufacture fishing gear degrades and enters marine trophic network, which means a new threat to the conservation of many species that ingest them accidentally.
Safer leisure activities on the coast
Fishing nets also endanger the safety in areas like the Catalan coast where there is so much leisure and tourism activity related to the seabed: particularly, they involve risks for navigation (nets become fouled in propellers, for example), swimmers and scuba divers. Besides its environmental impact, lost fishing gear produces a bad image that discourages enjoying nature and tourism.
The protocol to remove lost nets in the Montgrí, Medes Islands and Baix Ter Natural Park is part of a project of the research group MedRecover; it designs a series of measures to prevent and mitigate fishing gear remains. The project, which can be extended to other parts of the Catalan coast, includes campaigns for sensitizing fishers; campaigns for detecting nets with the collaboration of fishers, swimmers, scuba divers and sailors, and the removal of nets with minimum environmental impact.