An invasive variety of seaweed is advancing along the southern Spanish coast, littering beaches and threatening biodiversity and ancient fishing practices that have driven the local economy for more than 3,000 years, according to CGTN.
Primarily affecting the beaches of Cadiz and the Strait of Gibraltar, the race is on to try to find a solution to the slimy invasion before it devastates another season for those whose livelihoods depend on fishing.
The ancient “Almadraba” trap-fishing method is a technique that dates back to Phoenician times and has remained relatively unchanged in more than 3,000 years.
It involves anchoring nets to the seabed for months and at the end of the season, collect their catch. One of the most important catches is tuna – from March to June, the fish start to migrate through the area.
But in recent years, the fishing nets have been clogged by the Japanese seaweed, Rugulopteryx okamurae, which is currently thriving in the conditions of the Mediterranean Sea. Those fishing the waters are also concerned it is wreaking havoc on tuna migration.
“Seaweed is proliferating in this area as never before,” says Antonio Ponce, captain of Conil Almadraba, a local fishing vessel.
“It has never happened before in my 35 years of Almadraba, but in the past four or five years, the seaweed has proliferated here and is destroying our nets with great economic costs and it is endangering Almadraba traditional fishing.”
As the 2020 Almadraba season draws to an end, fisherman have found once again that the seaweed has used the underwater network of nets as a support, creating an underwater curtain of the marine plant that has scared away many of the tuna, a fish that looks for clear waters.
According to researchers from the University of Seville, the Rugulopteryx okamurae has been in the Mediterranean since 2002, as well as being found in the waters in northern Africa.
There are theories that the seaweed mixes with the ballast water in ships’ hulls, allowing it to be carried to the coastal waters of southern Spain.
Read full story online.