14 DAY TRIAL // An international team of researchers led by the Forest Technology Center of Catalonia, has conducted the first large-scale study of the threats that endemic Mediterranean fish are facing.
The study showed that the biggest menaces are invasive species along with the over-exploitation of the waters, and this could lead some fish species to extinction.
The team analyzed the information provided by the International Union for the Conservation of Nature (IUCN) Center for Mediterranean Cooperation, concerning the conservation status of native continental fish species in the Mediterranean basin.
They traced 10x10 km areas in the Mediterranean basin and calculated the number of fish species affected by different types of man-made factors, or pressures, like pollution, water extraction, invasive species, reservoirs, agriculture and over-fishing.
“This allowed us to describe the geographical variation in the impacts caused by the various pressures, which could then be related to the extinction risk for the fish communities,” Miguel Clavero, lead author of the study and a researcher from the Landscape Ecology Group of the Forest Technology Center of Catalonia, told SINC.
The research assessed the geographical distribution of pressures that have a negative impact on biodiversity, and the degree of threat they represent for native freshwater fish communities, in the Mediterranean basin.
All data included 232 fish species and their range of distribution, and was used on two geographical scales: the 10x10 km areas and river basins.
The researchers also accounted for two complementary indicators on extinction risk, according to the IUCN categories of threat.
Clavero said that “the continental fish of the Mediterranean basin are one of the most threatened biological groups in the world.
“The Iberian Peninsula is one of the areas in which invasive species have the greatest impact on native fish,” he explains.
He adds that “fish communities are exposed to the greatest threat of extinction when the most significant pressures are the impact of invasive species and over-exploitation of water resources.”
These two factors are causing the loss of biodiversity among continental fish in the Mediterranean, and this conclusion supports previous studies on the matter.
The best example of the consequences of over-exploitation of water resources in in the “the upper basin of the Guadiana (including the Tablas de Daimiel wetlands)", the scientists said.
The study has been published in the journal Diversity and Distributions.