UIB scientists confirm that protecting the Menorca Channel helps marine species adapt to environmental changes

PalmaProtecting the sea has a direct effect on the genetic diversity of marine species. A study by the UIB, which counted on the participation of researchers from the Spanish Institute of Oceanography (IEO-CSIC) and the Institute of Marine Research (IIM-CSIC), concludes that protecting marine ecosystems fosters the genetic diversity of the species that live there.

The study analyzed four species of fishing interest: the striped red mullet (Mullus surmuletus), the comber (Serranus cabrilla), the small red scorpionfish (Scorpaena notata) and the common octopus (Octopus vulgaris). The evidence is clear: the analyzed marine animals living within the Menorca Channel fishing protection zone, where trawling has been prohibited for ten years, "consistently present higher genetic diversity." In all four species, specimens from the protected area showed more diversity in the analyzed DNA fragment than specimens from two areas that are open to fishing.

Genetic diversity is the variety found in the DNA of individuals of the same species and "can be understood as a biological toolbox": the more varied the tools, the more possibilities a population has to face changes in the environment, diseases, or other problems and pressures.

"The results show that protecting marine habitats can help preserve the genetic variety of species, in addition to favoring their populations. This variety is important for species to be able to respond to future changes," explains Noemi Pasini, lead author of the study and researcher of the Human and Evolutionary Genetics (HEGEN) research group at the UIB. Pasini adds that incorporating genetic data into fisheries monitoring could help in making more effective conservation decisions.

More intensive fishing, less variety

After the protected area in the Menorca Channel was created in 2016, part of the fishing activity shifted to other sectors. The displacement was especially clear in the zone open to fishing closest to the protected area.

By comparing vessel records with genetic data, researchers have found a relationship between fishing activity and genetic diversity: areas where fishing had increased or been maintained generally showed less diversity.

The results also indicate that, even though fish and other marine animals move between zones, this exchange may not be enough to compensate for the effects of intense and continuous fishing pressure. Thus, fishing could cause rare genetic variants to disappear sooner than new individuals can arrive to introduce them.

How the study was conducted

The team analyzed nearly 400 specimens collected between 2021 and 2023 in three areas of the Menorca Channel. They compared a fragment of mitochondrial DNA called COI. This fragment is often used as a kind of genetic barcode to identify and compare organisms.

The researchers also studied vessel activity records between 2009 and 2023 and carried out simulations to analyze how populations might have changed over time.

The authors point out that the study analyzes only a fragment of the mitochondrial DNA. Therefore, the data are a first indicator and do not replace broader studies that analyze a larger part of the genome. Even so, this type of analysis is simple and affordable, and could complement the monitoring of protected areas.

Overall, the results suggest that the fishery protection zone can contribute to conserving exploited populations and their genetic variety. This information can be useful for planning a more sustainable management of marine resources.

Institutional support

The study was conducted within the framework of the MARFISH project (PDR2020/69–ITS 2017-006), funded by the Government of the Balearic Islands through the Sustainable Tourism Tax Fund. The CANAL campaigns were part of the SosMed project, funded by the European Union through Next Generation funds and developed through an agreement between the Ministry of Agriculture, Fisheries and Food and the Spanish National Research Council, through the Spanish Institute of Oceanography.

The study has been published in the scientific journal Biodiversity and Conservation.