17 Aug 2020

NENAVADNI NAVADNI DELFIN I THE UNCOMMON COMMON DOLPHIN

 

 

Društvo Morigenos je v uveljavljeni mednarodni znanstveni reviji Aquatic Conservation: Marine and Freshwater Ecosystems objavilo pregledno raziskavo o pojavljanju navadnega delfina v Tržaškem zalivu in severnem Jadranu.


Navadni delfin (Delphinus delphis) je bil nekoč v Jadranskem morju in celotnem Sredozemlju nekaj povsem navadnega. Toda od 1970-ih let naprej je ta vrsta v Jadranu in drugih delih Sredozemlja postala tako redka, da je sredozemska populacija na Rdečem seznamu Mednarodne zveze za varstvo narave (IUCN) opredeljena kot Ogrožena. Vrsta delfinov, ki sicer stalno živi ob slovenski obali in v severnem Jadranu ter jo v društvu Morigenos redno preučujemo, ni navadni delfin, temveč velika pliskavka (Tursiops truncatus). Nekoč je vode Jadrana naseljeval tudi navadni delfin, a je s tega območja praktično povsem izginil. Zadnjih trideset let ga v Jadranu obravnavamo kot regionalno izumrlo vrsto, k čemer je najverjetneje prispevalo predvsem namerno in sistematično pobijanje v sredini 20. stoletja. Takrat sta Italija in nekdanja Jugoslavija izplačevali denarne nagrade za vsakega ubitega delfina, saj se jih je obravnavalo kot škodljivce, ki z ribištvom tekmujejo za ribolovne vire. Poleg omenjenega ubijanja sta verjetna vzroka za upad populacije tudi pomanjkanje hrane zaradi prekomernega ribolova ter splošna degradacija morskega okolja.

 

Nekoč stalna, danes izjemno redka vrsta

Viri iz 1970-ih let navajajo, da so bile zadnje večje skupine navadnih delfinov na območju Tržaškega zaliva opažene v 1940-ih letih. Od takrat pa vse do danes nimamo niti enega samega zanesljivega zapisa te vrste v celotnem Tržaškem zalivu, vse do primerov dokumentiranih v tej raziskavi. Tudi naše 18-letne sistematične raziskave potrjujejo, da je na tem območju stalno prisotna le velika pliskavka. Zanimivo je, da je v slovenski strokovno-poljudni literaturi navadni delfin kljub temu naveden kot slovenska avtohtona vrsta, kljub temu, da pravzaprav ni niti enega samega dokumentiranega primera opažanja, najdbe ali pojava te vrste na območju Slovenije.  Spiridon Brusina, hrvaški naravoslovec, je v zapisih iz leta 1888 poročal o enem poginulem primerku iz Žavelj pri Trstu, ki naj bi ga nekoč hranili v Tržaškem prirodoslovnem muzeju. Omenjenega primerka Tržaški prirodoslovni muzej že dolgo ne hrani več, tudi če ga kdaj je. Na podlagi tega zapisa, ter glede na to, da je razdalja med Žavljami in slovensko-italijansko mejo le nekaj kilometrov, je bil navadni delfin uvrščen na seznam sesalcev Slovenije, pod predpostavko, da je v nekem trenutku moral prečkati tudi slovenske vode. Poleg tega je vrsta uvrščena tudi v slovenski Rdeči seznam ogroženih vrst sesalcev kot Ogrožena. Vendar pa navadni delfin v slovenskih vodah nikoli zares ni bil dokumentiran, vse do primerov, ki jih omenjamo v nadaljevanju.

 

Prvi potrjeni primeri v Tržaškem zalivu in Sloveniji

Prav zaradi redkosti so vsa opažanja te vrste v Jadranu in Sredozemlju danes nekaj posebnega in pomembnega, zato jih je pomembno dokumentirati. V društvu Morigenos smo navadnega delfina med leti 2009 in 2012 večkrat dokumentirali na območju Tržaškega zaliva, tako na podlagi neposrednih opažanj na morju, kot tudi na podlagi najdenih poginulih živali. Naravne oznake na hrbtnih plavutih so nam omogočile foto-identifikacijo (prepoznavanje osebkov po naravnih oznakah s pomočjo fotografij) nekaterih od teh, s čemer smo ugotovili, da so se v tem obdobju tukaj pojavili vsaj štirje različni osebki.

 

Prvi potrjeni primer te vrste v Sloveniji in Tržaškem zalivu smo dokumentirali leta 2009, ko so potapljači pred Izolo s plovila posneli delfina in fotografije posredovali društvu Morigenos. V društvu smo na podlagi fotografij nemudoma ugotovili, da gre prav za redkega navadnega delfina. Leto zatem smo v pristanišču Monfalcone (Tržič) dokumentirali samico z mladičem, ki se je tam zadrževala več mesecev. Na podlagi foto-identifikacije smo s pomočjo kolegov iz Grčije ugotovili, da je ta samica leta 2008 že bila opažena v Jonskem morju v Grčiji, več kot 1000 km stran. Njena pot do Tržaškega zaliva predstavlja doslej najdaljše dokumentirano potovanje pri tej vrsti na svetu, o čemer smo že poročali pred leti. Njen mladič je v začetku leta 2011 žal izginil, kar glede na njegovo starost najverjetneje pomeni, da je poginil. Njegovo mamo smo na območju Tržaškega zaliva videvali še nekaj mesecev, nakar je tudi ona izginila. Istega leta smo pred Izolo našli zelo razpadlo truplo delfinjega mladiča. Zaradi razpadlosti ni bilo možno ugotoviti za katero vrsto gre, vendar smo na podlagi natančnega pregleda očiščenih lobanjskih kosti ugotovili, da gre za navadnega delfina. Navadni delfini se namreč od vseh drugih vrst delfinov razlikujejo prav po zgradbi lobanje, saj imajo nebnico (kost ustnega neba) posebej oblikovano v dva žleba. Čeprav je nemogoče ugotoviti ali gre za istega mladiča, ki smo ga pred tem videvali s svojo mamo, je zelo velika verjetnost, da gre resnično za isto žival. Leta 2012 pa smo pred Piranom fotografirali še enega navadnega delfina, na podlagi naravnih oznak pa potrdili, da gre za novi osebek, ki ga doslej še nismo zabeležili.

 

Zanimivo je, da je bilo na tem območju v razmeroma kratkem obdobju opaženih razmeroma veliko primerkov te vrste, sploh glede na njeno redkost in skupno število vseh dokumentiranih primerov v celotnem Jadranu. V okviru raziskave smo namreč opravili tudi temeljit pregled literature in dosedanjih zapisov o pojavljanju te vrste v celotnem Jadranu. A vendar navadni delfin v severnem Jadranu zaenkrat ostaja redka vrsta. Če se bo sčasoma v večjem številu vrnila v Jadran, zaenkrat težko rečemo. Na žalost so možnosti za to precej majhne, saj nikjer v Sredozemlju ne beležimo porasta številčnosti ali opažanj. Upamo pa, da bo ta raziskava služila kot izhodišče in spodbudila poročanje o morebitnih prihodnjih primerih, za boljši vpogled v pojavljanje navadnih delfinov v Jadranu. Raziskava je prosto dostopna na: https://onlinelibrary.wiley.com/doi/full/10.1002/aqc.3407

 

V kolikor na morju opazite kite ali delfine, vas prosimo, da nam to sporočite na 031 77 10 77, saj nam s tem pomagate zbirati pomembne in koristne informacije o teh živalih.


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Morigenos has published a new review study on the occurrence of common dolphins in the Gulf of Trieste and the northern Adriatic Sea, published this week in the renowned scientific journal Aquatic Conservation: Marine and Freshwater Ecosystems.

 

The common dolphin (Delphinus delphis) used to be very common in the Adriatic Sea and other parts of the Mediterranean Sea. However, from the 1970s onwards it had become so rare that the Mediterranean population is now listed as Endangered on the Red List of the International Union for the Conservation of Nature (IUCN). The dolphin species which is otherwise regularly present in the Gulf of Trieste and the northern Adriatic Sea, and regularly studied by Morigenos, is the bottlenose dolphin (Tursiops truncatus). The waters of the Adriatic Sea were once also inhabited by the common dolphin, but is not generally absent from this region. During the last 30 years, this species is considered as regionally extinct in the Adriatic Sea, likely due to intentional and systematic killing during mid 20th century. Back then, both Italy and the former Yugoslavia used to pay monetary rewards for every dolphin killed, because dolphins were considered pest that compete with the fisheries. Apart from direct kills, the population declines are likely also due to overfishing and the general degradation of the marine environment.

 

Once common, today extremely rare

Sources from the 1970s report that the last large groups of common dolphins in the Gulf of Trieste were seen in the 1940s. Since then, there have been no records of this species from the Gulf of Trieste, nor from nearby areas, until the records presented here. Our own 18-year systematic research also shows that the bottlenose dolphin is the only regular dolphin species in these waters. Interestingly, despite this, in Slovenian popular science literature, the common dolphin is nevertheless listed as a native Slovenian species, even though there are no actual documented cases of this species in Slovenia. A report from 1888 refers to a dead specimen from Zaule near Trieste, supposedly preserved in the Trieste Museum of Natural History. The museum no longer holds that specimen, even if it did so in the past. Based on this record, and given that the distance between Zaule and the Slovenian–Italian border is only a few kilometres, the common dolphin was included in the list of mammals of Slovenia, on the premise that it must have crossed Slovenian waters at some point. The species is also listed in the Slovenian Red List of Mammals as Endangered. However, the common dolphin has never actually been documented in Slovenian waters at any point in history, prior to records reported here.

 

First confirmed records in the Gulf of Trieste and Slovenia

Due to their rarity, all records of common dolphins in the Adriatic and many other Mediterranean areas today are very special and important, so it is vital to document them. We documented several records of common dolphins in the Gulf of Trieste between 2009 and 2012, through sightings of live animals or recovery of dead stranded animals. Dorsal fin markings allowed the photo‐identification of some of these, suggesting that at least four different live individuals occurred here in recent times.

 

We documented the first confirmed case of the common dolphin in Slovenia and the Gulf of Trieste in 2009, when divers photographed a dolphin from a boat, off Izola, and sent photographs to Morigenos. Based on these photographs we immediately determined that this was the rare common dolphin. A year later we documented a female with a calf in the port of Monfalcone, where they stayed for several months. Based on photo-identification and with the help of our colleagues working in Greece, we discovered that the female had already been sighted in the Ionian Sea in Greece, more than 1000 km away. Her trip to the Gulf of Trieste represents the longest documented movement in this species worldwide, which we reported some years ago. Unfortunately, her calf disappeared in early 2011, which likely meant it had died. We kept seeing the female for a few more months, after she left the area. The same year we recovered a highly decomposed carcass of a dolphin calf near Izola. Due to advanced carcass decomposition, we could not immediately determine the species. However, after carefully examining the cleaned skull bones, we were able to identify the animal as the common dolphin. Common dolphins are distinguishable from all other dolphin species by the anatomy of their skull, which features special grooves in their palatal bone. Even though it is impossible to determine whether this was the same calf we had observed before, it is highly likely to be the same animal. Finally, in 2012 we photographed another common dolphin off Piran. Photo-identification showed that this was a new individual, not seen in previous years.

 

In our study, we also reviewed all published records of this species in the Adriatic to date. It is interesting that our new records are relatively numerous for such a short time period, especially considering the rarity of the species and the total number of documented cases in the entire Adriatic Sea to date. Unfortunately, the species continues to be rare in the region. It is difficult to say if the species is likely to make a comeback to the Adriatic Sea. The chance for that are likely slim, as there is currently no evidence of any increase in common dolphin abundance or sightings anywhere in the Mediterranean Sea. But hopefully this contribution can serve as a baseline and encourage potential future cases to be reported, in order to provide further insights into the occurrence of common dolphins in the region. The study is freely available at: https://onlinelibrary.wiley.com/doi/full/10.1002/aqc.3407

 

If you see whales or dolphins in the Gulf of Trieste, please report your sightings to +38631771077 and help us collect important information about these animals.

 

 

  

 

 

11 Aug 2020

Nova raziskava v kateri je sodelovalo društvo Morigenos I New study participated by Morigenos

 


Društvo Morigenos je sodelovalo pri raziskavi prehranjevalne ekologije delfinov v zalivu Ambracia v Grčiji, ki je bila ta teden objavljena v uveljavljeni reviji Marine Mammal Science (https://onlinelibrary.wiley.com/doi/abs/10.1111/mms.12725), vodili pa so jo raziskovalci Univerze v Barceloni ter raziskovalnega inštituta Tethys. V skoraj povsem zaprtem zalivu Ambracia na severozahodu Grčije živi ogrožena skupnost približno 150 velikih pliskavk, ki jo preučujejo raziskovalci raziskovalnega inštituta Tethys in ki je skorajda popolnoma ločena od sosednjih populacij v Jonskem morju. Do sedaj so informacije o njihovih prehranjevalnih navadah izhajale izključno iz vzorcev lusk rib, naključno zbranih na vodni gladini, ko so se delfini prehranjevali tik ob površini. V tej raziskavi pa so znanstveniki prehrano delfinov ugotavljali s pomočjo stabilnih izotopov ogljika in dušika v vzorcih tkiva delfinov in njihovega plena. Rezultati so pokazali, da se delfini na tem območju prehranjujejo predvsem s šuri, špari, ovčicami, sipami, sardoni, sardelami in glavači. Raziskava je podala nova spoznanja o prehranjevalni ekologiji velikih pliskavk, saj se le-ta med posameznimi populacijami lahko zelo razlikuje. Raziskava pa je pomembna tudi z vidika boljšega razumevanja medsebojnih interakcij med morskimi sesalci in ribiškimi aktivnostmi, saj so nekatere prehransko pomembne vrste za delfine tudi komercialno pomembne za ribištvo.

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Morigenos participated in a study investigating the feeding ecology of dolphins in the Gulf of Ambracia in Greece, led by researchers from the University of Barcelona and Tethys Research Institute and published this week in the journal Marine Mammal Science (https://onlinelibrary.wiley.com/doi/abs/10.1111/mms.12725). The almost completely enclosed Gulf of Ambracia, in northwestern Greece, hosts a threatened community of about 150 bottlenose dolphins, which are largely separated from neighbouring populations in the Ionian Sea and are being studied by Tethys Research Institute. Until now, information on their feeding habits was derived exclusively from fish scale samples collected during surface‐feeding events by dolphins. But in this study, scientists determined the diet of dolphins using stable isotopes of carbon and nitrogen in the tissue samples of dolphins and their prey. Results showed that the dolphin diet was mainly based on Atlantic horse mackerel, annular and striped sea bream, cuttlefish, European anchovy, European pilchard, round sardinella and gobies. The study provides new insights into the feeding ecology of bottlenose dolphins, which can vary substantially among different populations. The study is also important for a better understanding of interactions between marine mammals and fisheries, as some dolphin prey species are also commercially important to fisheries.


13 May 2020

Akustični monitoring :: Acoustic monitoring



Končno, naša akustična oprema je spet tu! Ker nam je kombinacija vzrokov, povezanih s situacijo COVID-19, preprečila, da bi naše akustične detektorje iz vode potegnili kot sprva načrtovano, smo jih morali v morju pustiti dlje. V veliko veselje in olajšanje nam je bilo, ko smo videli, da so še vedno tu. Veselimo se analiziranja podatkov, ki so jih v tem času zbirali.
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Finally, our acoustic equipment is back, safe and sound (no pun intended)! After a combination of reasons related to the COVID-19 situation prevented us from retrieving our acoustic loggers as originally scheduled, we were forced to leave them in the sea longer. We were happy and relieved to find they were still there. We look forward to analysing the collected data! 

8 May 2020

Magistrska naloga o vplivu ribištva na delfine v Tržaškem zalivu :: Master thesis on the impacts of fisheries on dolphins in the Gulf of Trieste



Iskrene čestitke Janji Hozner, prijateljici in nekdanji udeleženki naših raziskovalnih taborov, ki je danes na Univerzi v Mariboru z odliko magistrirala na študijskem programu Biologija in ekologija z naravovarstvom, z magistrsko nalogo z naslovom “Vpliv ribištva na vedenje in telesne poškodbe velike pliskavke (Tursiops truncatus) v Tržaškem zalivu”, ki je bila opravljena v sodelovanju z društvom Morigenos. Bravo Janja!

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Huge congratulations to Janja Hozner, a friend and former participant to our research courses, who got awarded her MSc degree with distinction in Biology and Ecology with Conservation at the University of Maribor, with a thesis titled “Impact of fisheries on the behaviour and body injuries of bottlenose dolphins (Tursiops truncatus) in the Gulf of Trieste”, carried out in collaboration with Morigenos. Well done Janja!

22 Apr 2020

Dan Zemlje I Earth Day





Danes je dan Zemlje. Naše Zemlje! Pazimo nanjo, vsak zase in skupaj.😊🐦🐝🐬🌲🌵🍄 
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Today is Earth day! Let's try to make every day an Earth day, individually and all together. 😊🐦🐝🐬🌲🌵🍄

26 Mar 2020

Dolphin Nevio


This is a dolphin Nevio.

Unlike dolphins from the "morning" and "evening" group, which like to swim in big groups, Nevio mostly prefers to be alone. Despite this, he can remain in acoustic contact with other dolphins over larger distances.

During these days be like Nevio - remain in contact with your friends at a distance.

Delfin Nevio



To je delfin Nevio.

Za razliko od delfinov iz “jutranje” in “večerne” skupine, ki radi plavajo v velikih skupinah, je Nevio večinoma najraje sam. Kljub temu je lahko v akustičnem (zvočnem) kontaktu z drugimi delfini na daljavo.

V teh dneh bodite kot Nevio – bodite v stiku s prijatelji na daljavo.
#ostanidoma

23 Mar 2020

Naše delo se je začasno ustavilo


Tudi naše delo se je začasno ustavilo. Skrbi nas, kako bo to vplivalo na naše društvo in naše delo. Upamo na čim hitrejše izboljšanje.
Vsi, ki nas želite podpreti v tem obdobju, to najlažje storite s posvojitvijo delfina. S tem prispevate k raziskovanju in zbiranju pomembnih podatkov o življenju delfinov v našem morju.
Več informacij na https://www.morigenos.org/posvojite-delfina-iz-slovenskega…/
Vnaprej se vam zahvaljujemo za podporo.

14 Mar 2020

A dolphin named Prešeren

Prešeren, a bottlenose dolphin which we first met on this year's Prešeren Day, came to have breakfast in Piran this week, in a fish restaurant with a view of Slovenia's highest mountain Triglav.


Delfin Prešeren

Delfin Prešeren, ki smo ga spoznali na letošnji Prešernov dan, je bil ta teden na zajtrku pred Piranom, v ribji restavraciji s pogledom na Triglav.


5 Mar 2020

Dolphin Research Courses



For everyone who loves the ocean, sun and marine mammal research, we are once again organising Dolphin Research Courses. The courses will be held in Piran, Slovenia, from June to end of August. If you are over 16 years of age you are more than welcome to join us and learn more about the lives of dolphins living in the Gulf of Trieste.

You can read more about the Dolphin Research Courses on the link: https://www.morigenos.org/en/dolphin-research-courses/.

For more information send an email to morigenos@morigenos.org

Poletni raziskovalni tabori





Za vse ljubitelje morja, sonca in znanstvenega raziskovanja morskih sesalcev tudi to poletje organiziramo raziskovalne tabore. Potekali bodo od junija do konca avgusta v Piranu. Na raziskovalne tabore vabimo vse, ki ste starejši od 16 let in vas zanima kako poteka delo raziskovanja delfinov v Tržaškem zalivu.

Več o raziskovalnih taborih si lahko preberete na povezavi: https://www.morigenos.org/raziskovalni-tabori/. 

Za dodatne informacije nam lahko pišete na morigenos@morigenos.org

12 Feb 2020

PREŠEREN-DOLPHIN DAY




Morigenos team spent the Slovenian cultural holiday (8th February – Prešeren Day) in the field. On Saturday and Sunday we carried out 155 km of navigation at sea and about 10 hours of land-based observations. On Prešeren Day we encountered two dolphins off Piran. One of them, called Nevio, is well known to us since 2008. The other was recorded for the first time and to commemorate the day, it was named Prešeren, after France Prešeren, Slovenia’s greatest poet.

PREŠERNOV DAN DELFINOV




V društvu Morigenos smo slovenski kulturni praznik preživeli na terenu. V soboto in nedeljo smo opravili 155 km navigacije na morju in okoli 10 ur opazovanj s kopnega, na sam Prešernov dan pa smo pred Piranom srečali tudi dva delfina. Prvega, po imenu Nevio, poznamo že od leta 2008, drugega pa smo srečali prvič. Slednji je ob obeležitvi tega pomembnega praznika dobil ime Prešeren.

15 Jan 2020

FIRST SIGHTING OF THE NEW DECADE



Today we had the first dolphin sighting in the new decade! We found a large group of dolphins along the shore of Piran (Slovenia), including mothers with calves. Most of the encountered dolphins are well known to us, as we now know some of them for 19 years. Those of you that adopted the female Moni in the past will be happy to know she was seen today with a calf. Many thanks to fisherman Boris who called us when he spotted dolphins. Such reports are highly valuable to us, as they enable us to collect additional data and therefore gain a better understanding of dolphins in the northern Adriatic. Morigenos carries out dolphin monitoring in the Gulf of Trieste year-round. 



If you spot dolphins in the area, please call us on +386 31 77 10 77, we will be most grateful!

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