About dolphins

The Gulf of Trieste and surrounding waters are important habitat for the dolphin population of the species bottlenose dolphin (Tursiops truncatus). This is the only species of whales and dolphins that is constantly present in our country, other species visit us less often.
The bottlenose dolphin belongs to a family of dolphins that includes 36 different species. This family also includes the common dolphin (Delphinus delphis), the striped dolphin (Stenella coeruleoalba) and the orca (Orcinus orca), also known as the “killer whale”.
Whales and dolphins are mammals. This means that they have a constant body temperature, breathe air from their lungs and produce live calves that suck up breast milk.

Want to learn more? Click on the markings and explore the characteristics of the bottlenose dolphin.

Did you know?

  • Dolphins are considered bioindicators – natural indicators of the state of the marine environment. Since they live very long (30-40 years) and because they are at the top of the food chain, we can indirectly control the state of the environment in which they live by observing the dolphin population.
  • Bottlenose dolphins are big animals. In the northern Adriatic they measure about 3 m and weigh about 230 kg.
  • Dolphins have 76-104 conical teeth in their mouths that only grow once and then grow for life.
  • Dolphins have good eyesight both above the surface and in the water, which is not the case for a man who does not see well in the water, or for a fish who sees well only in the water.
  • They have to eat 4-5 kg of fish a day.

What are the threats to dolphins?


We flush a lot of harmful substances into the sea that we use daily. These substances are toxic chemical compounds that travel all the way through the food chain to dolphins and accumulate in their bodies. They can weaken the immune system, suppress reproductive potential, and cause cancer or even death.
There is also more and more garbage in the sea, such as plastic (plastic bags, packaging, gloves), rubber and other materials that animals mistake for food. Ingestion may lead to intestinal blockage and internal damage and death.


Underwater noise

For dolphins, sound is extremely important, because with its help they can communicate, orientate, and hunt. Loud underwater noise disturbs them during rest, play and mating and prevents effective communication or search for food.


Maritime transport

Dense traffic can interfere with dolphins’ daily activities and even cause dolphins to disappear from certain important areas. If there are many loud vessels that do not follow the rules of appropriate behaviour for observing dolphins (or do not spot the dolphins), dolphins often stop feeding and resting and leave the areas that are important to them. Aggressive high-speed or inattentive vessels can cause collisions with dolphins. As a rule, such collisions cause serious injuries to dolphins and sometimes even death.

Interaction with fisheries

Sometimes dolphins become entangled in fishing nets and die. In some cases, dolphin mortality due to entanglement in fishing nets is extremely high, but this is fortunately not the case for Slovenia. Overfishing can lead to a decline in the number of fish that are the staple food of bottlenose dolphins, and inappropriate fishing can lead to the destruction of underwater habitats, which also leads to the depletion of marine resources.
Would you like to know the dolphins even better? Visit us at the Dolphin Centre.
Meet other inhabitants of the northern Adriatic.



Loggerhead sea turtle

Sea turtles breathe with their lungs and their body temperature depends on the surrounding temperature. They have adapted to the marine environment by turning their limbs into flippers and their shell into a more hydrodynamic shape. Unlike their terrestrial relatives, they cannot retract their heads and legs into their shell.
The Slovenian part of the Adriatic is mainly inhabited by the loggerhead sea turtles (Caretta caretta) from May to November, as this area is an excellent feeding ground for them. They move south in winter when our waters become too cold for them.
The common dolphin (Delphinus delphis) was once a permanent resident of the northern Adriatic, but has been extinct for the last three decades. In the last 30 years, sightings of common dolphins in the northern Adriatic have been extremely rare and mostly restricted to single animals. In 2009, 2010, 2011 and 2022, the species even appeared in the Gulf of Trieste, including in the vicinity of Izola, Debeli Rtič and the Port of Koper. Nevertheless, today the common dolphin is considered a regionally extinct species in the Adriatic Sea.

Fin whale

In November 2020, researchers from Morigenos tracked and observed two fin whales (Balaenoptera physalus), following a report from a Slovenian fisherman.
The fin whale is the second largest animal in the world and the only resident baleen whale in the Mediterranean, and is recorded in the northern Adriatic on average every few years. In the northern hemisphere, they can grow up to 22.5 m and 50 tonnes, while their southern hemisphere counterparts can grow up to 26 m and 80 tonnes. They feed mainly on small shrimps called krill and some small fish.
The fin whale is classified as vulnerable on the Red List. The main threats to this species in the Mediterranean are collisions with high speed boats, underwater noise, chemical pollution and microplastics.
We photographed both whales and obtained aerial images of both animals. The photographs of the dorsal fins and other body parts will allow us to work with colleagues abroad to determine whether the whales have been identified elsewhere, and the aerial photographs will allow us to determine their physical condition.

Humpback whale

In February, March and April 2009, humpback whale (Megaptera novaeangliae) was present in the Slovenian sea and attracted a lot of public attention.
On 16 February, Morigenos researchers identified the species and confirmed that it was indeed a humpback whale. It was a young adult animal, about 10-12 metres long, which appeared to be in normal condition and showed no obvious signs of disease or problems.
The Morigenos team monitored the whale and observed its behaviour, movements and breathing patterns. The whale’s physical appearance, dive patterns and behaviour were completely normal.
We have also informed colleagues in other parts of the Mediterranean and the international scientific community, who have already reacted to the news. We have already compared the photos we took with an international database of over 6000 humpback whales in the Atlantic. It was found that the whale that appeared in our country had not yet been recorded in the international database.