Malta’s bottlenose dolphin population estimated at 79

Dolphins may have adorned Malta’s first post-independence coat of arms but statistical information on their actual numbers in Maltese waters has been sketchy.

Some new light on numbers has been cast by Malta’s final report for the EU’s Marine Strategy Framework Directive, which suggests their population is stable.

Systematic surveys confirm the regular presence of the bottlenose dolphin (Tursiops truncates) in Maltese waters, whose total population in 2014 ranged from 79 to 224, with 79 considered more realistic figure. The estimate was based on photo identification of marked individual dolphins, covering 780 hours out at sea to monitor almost 6,000 kilometres square of water over two years.

Based on 59 sightings of pods of bottlenose dolphins between 2013 and 2016, it is believed the mammal is widely distributed in Maltese waters with sightings being more common off the southern and western coasts.

The maximum number observed in pods ranged between 10 and 40, with a median of 12 individuals, again a sign of a stable size.

Two other dolphins, the short beaked common dolphin and the striped dolphin, also frequent Maltese waters. Between 2013 and 2016, 35 sightings of the common dolphin were recorded, mostly in the southwestern part of Malta. The striped dolphin was observed in 22 sightings.

Other marine mammal species like sperm whales were also observed, occasionally. Risso dolphins were sighted four times between June and July of 2016, while sperm whales were recorded five times in August 2013, south of Filfa.

No by-catch of marine mammals by fishermen has been recorded during 2013-2018, corroborating claims in previous reports to the EU that Maltese fishing methods are not a significant threat to cetaceans.

But the report raises the possibility of under-reporting. In light of this, the fisheries department is launching a pilot study for on-board observations to log accurate data on species that are incidentally caught.

Marine litter, underwater noise and maritime traffic, including collision and pollution impacts, remain potential pressures on marine mammals. A Conservation Plan for the loggerhead turtle and the bottlenose dolphin in Maltese waters is set to address these pressures. But as regards noise, the report identifies a need for more data before implementing targeted management measures.