MORIGENOS RESEARCHERS DISCOVER A NEW WAY OF IDENTIFYING DOLPHINS

Morigenos researchers have discovered that individual dolphins can be identified by their faces, “inventing” a novel method of dolphin identification. They presented their findings in a study, published today in Marine Mammal Science, the central scientific journal for studies of marine mammals: http://onlinelibrary.wiley.com/doi/10.1111/mms.12451/full

It has long been known that individual dolphins can be identified by natural markings on dorsal fins. Thanks to these markings, we know that about 150 dolphins live in the Gulf of Trieste, studied by Morigenos researchers since 2002. But markings on fins can change, and calves are usually not sufficiently marked to allow identification at all. Therefore, additional means of telling dolphins apart can be very useful. A few years ago, Morigenos researchers discovered that dolphins can also be identified by their faces, which was not known previously. This was first discovered by Tilen Genov, Morigenos president and the first author of the study, while studying dolphins in Slovenian waters and the Gulf of Trieste. Together with an international team of scientists, he designed a study in which participants both experienced and inexperienced in dolphin fin identification were asked to match photographs of dolphin faces. Results showed that both groups of participants can tell individual dolphins apart based on their faces, even when comparing the left side of the face to the right one. The study also showed that facial features in dolphins are consistent over time and can be used over the long term.

This new method cannot replace the identification based on dorsal fins, but it can complement it. Unlike dorsal fins, faces are not subject to the same level of change due to external influences, and may therefore be more reliable over long periods. This new method is also very applicable to calves, which usually do not carry sufficient dorsal fin markings to be recognisable after they leave their mothers, and can therefore help increase cross-generational knowledge. It may be particularly suited to species that do not carry many markings on dorsal fins, or those that lack dorsal fins altogether.

This study, published in an internationally renowned scientific journal, shows that even research originating from countries with very little sea (Slovenia) can have wider implications for the study of marine mammals globally.

SLOVENSKI RAZISKOVALCI ODKRILI NOV NAČIN PREPOZNAVANJA DELFINOV

Raziskovalci društva Morigenos so odkrili, da je posamezne delfine možno razlikovati na podlagi obrazov in s tem “izumili” novo metodo identifikacije delfinov. Svoje izsledke so predstavili v raziskavi, ki je bila danes objavljena v mednarodno priznani reviji Marine Mammal Science, osrednji znanstveni reviji za znanost o morskih sesalcih: http://onlinelibrary.wiley.com/doi/10.1111/mms.12451/full

Že dolgo je znano, da je posamezne delfine možno prepoznavati na podlagi naravnih oznak na hrbtnih plavutih. Prav zaradi tovrstnih oznak danes vemo, da v slovenskem morju živi okoli 150 delfinov, ki jih raziskovalci društva Morigenos preučujejo in spremljajo že od leta 2002. Toda oznake na plavutih se spreminjajo, težava pa je tudi v tem, da mladiči na plavutih še nimajo oznak, po katerih bi jih lahko prepoznavali. Dodatni načini prepoznavanja delfinov so torej lahko zelo koristni. V društvu Morigenos so ugotovili, da je delfine možno prepoznavati na podlagi njihovih obrazov, kar doslej ni bilo znano. Zadevo je odkril Tilen Genov, predsednik društva Morigenos in prvi avtor raziskave, in to prav pri delfinih iz Tržaškega zaliva. Skupaj z mednarodno ekipo znanstvenikov je zasnoval študijo, v kateri so morali izkušeni ter neizkušeni opazovalci primerjati fotografije obrazov delfinov in jih pravilno povezati. Rezultati so pokazali, da tako izkušeni kot tudi neizkušeni opazovalci lahko ločijo posamezne osebke na podlagi njihovih obrazov, celo kadar primerjajo levo in desno stran obraza. Raziskava je prav tako pokazala, da so obrazne poteze pri delfinih dolgotrajne in omogočajo identifikacijo na dolgi rok.

Ta nova metoda prepoznavanja sicer ne more nadomestiti identifikacije na podlagi plavuti, lahko pa jo dopolnjuje. Obrazi za razliko od plavuti niso podvrženi tolikšni meri sprememb zaradi zunanjih vplivov, zato so lahko dolgoročno bolj zanesljivi. Nova metoda je primerna tudi za mladiče, katerih plavuti navadno niso dovolj označene, da bi jih lahko zanesljivo prepoznali tudi takrat, ko se osamosvojijo in zapustijo svojo mamo, zato lahko izboljša poznavanje medgeneracijskih povezav v populaciji. Še posebej obetavna utegne biti pri tistih vrstah delfinov, ki na plavutih navadno nimajo prav dosti oznak, ali pri vrstah, ki hrbtne plavuti sploh nimajo.

Ta raziskava, objavljena v uveljavljeni mednarodni znanstveni reviji, je še en primer, ki kaže, da ima lahko tudi raziskovanje delfinov v slovenskem morju širši pomen za poznavanje morskih sesalcev na svetovni ravni.