STA, 17 August 2020 - A study has shown that an endangered subspecies of the common dolphin visited the Gulf of Trieste, which includes the bulk of Slovenian territorial waters, between 2009 and 2012, after a long period of absence due to systematic culling and lack of food.
The marine mammal association Morigenos, which conducted the study, notes that the appearances of the subspecies in the Adriatic Sea and the Mediterranean used to be something completely usual.
But since the 1970s, it has become so rare that it was labelled as endangered by the International Union for Conservation of Nature (IUCN).
According to the association, this was most probably owing to deliberate and systematic killing of the animal in the mid-1950s.
"At the time, Italy and the former Yugoslavia were paying rewards for each dolphin killed, because they were treated as pests who compete for fish with the fisheries sector," Morigenos said in a press release on Monday.
An additional possible cause for the decline of its population was the lack of food due to over-fishing and overall degradation of the marine environment.
While the last large groups of the common dolphin were seen in the Gulf of Trieste in the 1940s, Morigenos has come up with some new findings based on direct observations and found carcasses.
The association has established by means of photo identification of the dorsal fin that at least four specimens appeared in Slovenian territorial waters between 2009 and 2012.
While the common bottlenose dolphin is constantly present in the Gulf of Trieste, the common dolphin remains a rare species in the Northern Adriatic and chances for its return in large numbers are rather slim.
"Researchers record no increase in the number or sightings anywhere in the Mediterranean," said Morigenos, which hopes the study will encourage reporting on future cases to get better insight in the occurrence of the common dolphin in the Adriatic Sea.
"Large marine predators are important for healthy ecosystems and in the long run they are beneficial for the fisheries sector and not harmful," the association concluded.
You can learn more about the work of Morigenos here, and also read the full study, Occurrence of common dolphins (Delphinus delphis) in the Gulf of Trieste and the northern Adriatic Sea, by Tilen Genov, Polona Kotnjek and Tina Centrih