It is not as famous as the Palamós shrimp, but the Norway lobster (scientific name Nephrops norvegicus) is one of the most appreciated crustaceans in the Mediterranean diet. The flavor of this shellfish has led to its high demand and fishing, to limits that have come to endanger its survival in some areas of the Catalan coast.
The creation and good maintenance of marine reserves in which trawling is prohibited is an effective and rapid response to face the local decline of this species. This is demonstrated by a study carried out by eight researchers from the Institut de Ciències del Mar (ICM-CSIC), whose results have been published in the journal Science of the Total Environment.
In this study led by Maria Vigo, the effectiveness of a small marine reserve that covers the Roses and Palamós (Girona) fishing grounds has been verified. The application of protection measures in this area has facilitated a notable increase in Norway lobster populations "in a much shorter time than expected", highlights the ICM-CSIC in an informative note on the results of the study.
The good recovery of the species is due to the ban on trawling at this point on the Catalan coast since 2017, a measure that came into force thanks to the establishment of a 10 km² marine reserve. This has also allowed the recovery of the morphology of the bottoms plowed by the trawl fisheries and the fauna associated with them.
Using remotely manned robots (better known as ROVs), the research team analyzed the populations of this emblematic Mediterranean species inside and outside the reserve, between 351 and 475 meters deep.
The use of underwater robots “allowed us to notice that the population of Norway lobster within the reserve doubled that of the control area, where fishing continues today. Likewise, we saw that the bottom habitats had recovered significantly within the protected area, while outside they presented trawl marks in at least 69% of the transects carried out”, explains Maria Vigo, lead author of the study.
For their part, Joan Navarro and Joan Baptista Company, principal researchers of the RESNEP project where this work is framed, highlight the acceptance of the fishermen from the Roses and Palamós guilds when it comes to prohibiting fishing activity in this small reserve.
“This opens the possibility of expanding this same action to other areas where this species and the marine ecosystem where it is present are also overexploited. In the end, the goal is to recover what is considered one of the most valuable crustaceans in European fisheries," the researchers add.
Normally, for the study of the species that inhabit deep habitats, experimental trawling is carried out that contributes to the "ploughing" of the seabed. "Underwater robots, on the other hand, allow for much more exhaustive and non-invasive monitoring of these species," says Jacopo Aguzzi, co-author of the study and an expert in the use of marine technology applied to the study of communities of species associated with the bottom.
In this case, the images and videos recorded by the robots allowed us to observe a considerable increase in the density and biomass of Norway lobster within the reserve compared to that of the areas adjacent to it. Likewise, they allowed us to notice how some species that share a habitat with the Norway lobster, such as the redfish (Helicolenus dactylopterus) and the garneo (Trigla lyra), which had also decreased due to trawling despite not being the target from this activity, have benefited from the establishment of the reserve, considerably increasing the biomass of their populations.
