Farmed sea bream tagged with a conventional dart tag ready for release. (Photo: Prevent Escape)
Microelectronic transmitters help prevent aquaculture fish escapes
Tuesday, July 12, 2011, 16:20 (GMT + 9)
Microelectronic acoustic transmitters implanted in the stomach of farmed sea bream and sea bass help a team of Spanish scientists to study the behavior of these fish and prevent their escape.
The signal emitted from these transmitters is picked up by underwater detectors located around the farms.
Using this tool, researchers from the Department of Marine Sciences at the University of Almería and from the Instituto Ramon Margalef determined that both species are not further away than 10 kilometers from the farms of origin.
The scientists also place a small plastic tag identifying the fish so that fishermen who catch tagged specimens can return them to the University of Almería.
This initiative of marking hatchery fish is developed in the framework of the Escape Prevention Programme, involving six other European countries, and the University of Las Palmas and the Basque Country.
The group of experts has already simulated the escapes of 2,000 sea bream and sea brass previously tagged in the Bay of Guardamar.
The idea is to study the ability the run-away fish have to feed themselves, their reproduction as free specimens, ecological effects and the possibility of recapture.
According to University sources, the escapes from the cages may occur because they get holed, break or sink.
The cages can be up to 15 meters deep and from 15 to 20 metres in diameter and contain between 50 and 100 tonnes of fish.
"While aquaculture escapes are further studied in northern Europe, especially in the case of salmon and cod, in the Mediterranean there is less knowledge on this subject," said Pablo Sánchez, project coordinator
This initiative aims to avoid major economic losses to aquaculture producers, and prevent potential environmental impacts such as the hybridization resulting from the cross breeding of genetically selected specimens with wild counterparts.
By Analia Murias