The Bottlenose dolphin (Tursiops truncatus, Montagu, 1821) is one of the 8 species of Cetaceans regularly present in the Mediterranean Sea. It belongs to the suborder of the Odontocetes, cetaceans characterized by having teeth, as well as the Stenella (Stenella coeruleoalba, Meyen 1833) and the Sperm whale (Physeter macrocephalus, Linnaeus 1758).

This dolphin has a sturdy build and can reach 3.5 metres in length, although on average its size is around 2.5 metres. The profile of the head shows the characteristic melon well pronounced, separated with a clear demarcation from the short and stocky rostrum.

The livery of these specimens shows different shades of grey with paler ventral areas and, depending on the age and the social and non social interactions, several signs and scars of various origin are observed. The dorsal fin, due to its shape and the presence of these signs, is a distinctive character used to distinguish the individuals thanks to the photo-identification techniques.

Like most cetaceans, bottlenose dolphins are gregarious animals and the composition of the groups (pods) varies according to sex, age, sexual maturity and social hierarchies.

Like other dolphins, also the Bottlenose dolphins possess a vast anthology of behavioral patterns in and out of the water, each with its own ethological significance.

In addition to these, Bottlenose dolphins produce a varied repertoire of acoustic emissions, such as whistles and clicks. Whistles have a communicative social function, and some (signature whistles) contain information about the identity of individuals. The clicks, of short duration or in sequence, are used for echolocation, the complex system of sound signal emissions with return wave reception. In this way, bottlenose dolphins, like other dentists, can orient themselves in space and collect environmental information even at a distance, for example thanks to the topographic representation of the seabed.

It is in this way that these animals are able to discriminate targets in the vicinity and identify their prey, such as fish, invertebrates and cephalopods, which characterize the very varied diet of this species easily adaptable to pelagic or coastal environments, where it often interacts also with fishing activities.


Dolphins are widely distributed in the Mediterranean. The bottlenose dolphin inhabits a wide variety of habitats, including continental shelf waters, lagoons and enclosed seas, the waters surrounding islands and archipelagos and also deep waters offshore. Physiographic variables, such as depth and distance from the coastline, may influence the dolphin distribution directly or indirectly by acting upon other biotic factors such as prey distribution, habitat structure, social interactions, predation risk, and breeding success.

The real extension and population size is not really completed established. Even if it is widely distributed in the Italian waters, in particular close to shorelines, this species is concentrated within the Pelagos Sanctuary, mainly along the Eastern Liguria and Tuscany with a population of about 1000 individuals and in the Northern and Central Adriatic, including also Croatian waters, with more than 5000 individuals recently estimated through aerial surveys. Other populations are reported around Sardinia and Sicily and close to the Campania shores. These population seems to be genetically differentiated: in fact, they tend to be resident in specific areas with an average movement of 120 km even if they are able to travel for more than 400 km between different places.

In the Mediterranean the group size is variable depending on geographical factors, preys availability and other seasonal factors.

Conservation status

Tursiops truncatus Mediterranean subpopulation is considered as vulnerable in the IUCN Red list of threatened species. Besides Habitat Directive (Appendix II and IV), Bottlenose dolphin is included in the Bonn, Bern and Barcellona Conventions (in all Appendix II), CITES (Appendix II) and ACCOBAMS (Annex I).
Concerning the justification for the Mediterranean listing (Vulnerable), this was based on inferred data trends between about 1940 and 2080 (six generations). The full justification states that “in northern portions of the Mediterranean basin, there is a well-known history of intentional killing, including extensive extermination campaigns conducted until at least the early 1960s, and there has been (and continues to be) substantial incidental mortality in fishing gear”.
It is not possible, however, to make robust estimates of either kind of mortality for other than short time periods and 65 limited areas within the total subpopulation range.
There is strong evidence that overfishing of dolphin prey has resulted in a form of habitat loss and degradation and likely also in a decline in area of occupancy.
Other factors, such as disturbance by marine traffic, may be contributing to those processes. High levels of contamination by pollutants are another source of concern.
Among the identified threats, only the extermination campaigns have ceased.

According to literature from the 19th century, “dolphins” were abundant throughout Mediterranean coastal waters. On the northern side of the basin, the animals were mostly seen as vermin, and one of the main concerns of fishery managers from the late 18th century onwards was to develop and deploy new means of killing the largest possible number of dolphins.
Conflict with fisheries was reportedly acute in several areas of Spain, France, Italy, and former Yugoslavia (today’s Slovenia, Croatia, Serbia and Montenegro), where thousands of animals were killed for bounties. Bottlenose and Common Dolphins were the main targets of the extermination campaigns in Mediterranean coastal areas.

Numbers of Bottlenose Dolphins in some areas where they were formerly high are now lower, and this pattern can reasonably be extrapolated to other areas in the northern part of the basin. Given this, a reduction in population size of more than 30% since 1940 is suspected.