Research
The main activity of the Morigenos Society is to explore the species Bottlenose Dolphin in the northern Adriatic Sea.
Dolphins in Slovenian waters have been studied and monitored since 2002, and the research is also carried out in the adjacent Croatian and Italian waters. The collection of scientific data enables better knowledge and more effective protection of the dolphin population living in these waters.
Research methods are used to determine the distribution of dolphins, their number, social structure, habitat use, eating habits, interactions with fisheries and the impact of tourism. The data are obtained through dedicated vessel expeditions, observation from land observation points, photo-identification, and acoustic monitoring.
Observation from land and on-board expeditions
If we want to study dolphins, we have to find them first. We do this in two ways: from land observation points and by boat.
When observing from land, we use binoculars and big-eyes (special binoculars with strong magnification). When dolphins are sighted, we record their location, behaviour, the state of the sea, the presence of vessels and other data in special forms.
Then we try to find the dolphins in the sea. Once we’ve spotted them, we slowly approach them with our exploration boat and begin tracking them. The vessel shall remain with the dolphins for one or more hours, depending on the number of dolphins in the group, their behaviour, weather conditions and other circumstances. We usually try to collect all the data as soon as possible and leave the group in less than an hour.
We study dolphins not only to satisfy our curiosity, but also to effectively protect dolphins with the collected data. First of all, we need to obtain general information about their lives and environment, we need to know what problems they face and what human impacts are most harmful to them, so that we could use this information for appropriate solutions.
When observing them, we always record the place of observation, the time, the number of dolphins, the presence of calves and the behaviour of animals. We are also constantly photographing dolphins, which is the most important part of our research.
Photo-identification
Photo-identification is the central method of our research. Individual dolphins can be identified by natural markings, such as cuts, scratches, and scars on the dorsal fins (as well as on other parts of the body), which occur as a consequence of interactions. Such markings can also be caused by other organisms (e.g. sharks) or diseases, and sometimes even unpleasant encounters with humans (e.g. collisions with vessels and ship’s propellers injuries, entanglements in fishing nets, etc.). Pigmentation patterns, the shape of the dorsal fin and other special features also help to identify individual animals.
We photograph dolphins so we can study their markings carefully. We compare the new photos with the old ones to determine whether we have seen the known dolphins, or whether we have encountered the new ones. Since 2002, over 400 dolphins have been photo-identified in Slovenian and adjacent waters, each dolphin was named and included in the catalogue.
With the help of photo-identification, we can determine the size of the dolphin population and monitor their number over time. In this way, we can observe whether the population is increasing, decreasing, or remaining equally large. We can also use this method to assess and study the annual survival rate, fertility rate, prevalence and distribution of dolphins, patterns of occurrence, migration, behaviour, social structure, habitat use and frequency of individual dolphins in individual areas.
How do dolphins get markings?
Dolphins are social animals that mostly live in groups. In these groups, there are constantly different interactions between individual dolphins; they can be gentle or coarse, friendly, or aggressive towards each other. Games and fights are an everyday thing in a dolphin’s life. The dolphins fight to establish a hierarchy within a group, to gain access to females, or because of other disagreements. Both in play and in more serious fights, dolphins bite each other, so their bodies are full of scratches and scars. On the skin of dolphins, you can see very clearly the teeth marks of other dolphins.
The dolphin’s dorsal fin is the most exposed part of the body. There is no bone or cartilage in it, only connective tissue, some fatty tissue, and dense intertwining of the vessels involved in body temperature control or thermo-regulation.
Since the rear edge of the fin is much thinner than the front part, it can be torn very quickly. The cut that forms never heals. Smaller or larger cuts are thus formed in the fins of dolphins. Such markings are long-lasting and are therefore used to identify individual dolphins.
Acoustic monitoring
Acoustic monitoring means that we use hydrophones (underwater microphones) to detect and record the natural sound of dolphins, thus identifying many interesting and important things.
In this way, the presence of dolphins can also be detected in bad weather, at night and in general when we cannot be in the field. In such a way we get an additional insight into their patterns of occurrence in our sea, their feeding and even interactions with fisheries. With a portable hydrophone, we can also record the sounds of dolphins.
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