Movements of bottlenose dolphins in Greece

Based on work done by Tethys in the coastal waters of western Greece, new information on bottlenose dolphin movements has become available.

A recent paper published in the Journal of Ecology reports movements of nine individual dolphins observed across three different study areas and photoidentified up to 265 km apart.

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Image: Location of the three study areas in Greece, and movements by nine bottlenose dolphins. From Bearzi et al. 2010.

Bearzi G., Bonizzoni S., Gonzalvo J. 2010. Mid-distance movements of common bottlenose dolphins in the coastal waters of Greece. Journal of Ethology. DOI: 10.1007/s10164-010-0245-x 
ABSTRACT: While bottlenose dolphins in Mediterranean waters often display a high level of site fidelity, movements across distant areas can occur. Such movements have important implications in terms of population viability, particularly in basins with low bottlenose dolphin densities. We report movements of nine individuals photoidentified up to 265 km apart in western Greece. Four showed a certain degree of site fidelity to one area across several years, but were also found elsewhere, with two individuals moving between two areas. This study provides further evidence that animals appearing to be ‘resident’ within a given area can temporarily leave and range widely.

A new dolphin investigation begins

We started a new investigation in the Northern Gulf of Evia (click on image to zoom out).

After having spent a part of the summer dealing with all the logistical aspects, Silvia and I finally moved to a convenient location in the central part of the Gulf. We set up a new field station and managed to get appropriate mooring facilities. We are now ready for work at sea.

OceanCare kindly provided funding to start this new enterprise, and lent a new 100HP engine. Work in the Gulf—done in the context of a collaboration between Tethys and OceanCare—should be conducted between autumn 2010 and spring 2011. Depending on the results, we will decide how the project may unfold in future years.

Some information on dolphins in the Northern and Southern Gulfs of Evia was produced in 2003 by researchers Zafiropoulos and Merlini (*), who reported a high density of bottlenose dolphins in the Northern Gulf. Since then, however, no systematic research was conducted.

Our new study intends to complement the existing information and if possible contribute a preliminary estimate of dolphin abundance, as well as information about status and threats, which may support management action.

The work is also intended to provide insight on dolphin ecology and behaviour in different habitats. It is an exciting opportunity to get to know more about dolphins living in the coastal waters of Greece and allow for comparisons among areas exposed to a variety of human impacts, based on work that is now being conducted in four study areas (the other three being the Amvrakikos Gulf, the Inner Ionian Sea archipelago and the Gulf of Corinth).

Giovanni Bearzi and Silvia Bonizzoni

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(*) Zafiropoulos D., Merlini L. 2003. A comparative ecological study of bottlenose dolphins (Tursiops truncatus) in South and North Evoikos Gulfs. 8th International Conference on Environmental Science and Technology, Lemnos island, Greece.

Gulf of Corinth: the 2010 research season ends

The dolphin research project in the Gulf of Corinth has recently concluded its second research season, scoring a total of 61 dolphin sightings.

We had many pleasant encounters with marine life. 

We saw all four cetacean species that inhabit the Gulf: bottlenose, striped, short-beaked common and a single Risso’s dolphin.

And also 402 encounters with jellyfish Cothyloriza tubercolata, 23 with loggerhead turtles Caretta caretta, 82 with tuna and 5 with swordfish.

Happy and satisfied about the work done this year, we are grateful to all the volunteers who participated in the field courses, helped us with the research and shared with us every single moment at sea. 



A big THANK YOU to our 63 volunteers who came from 16 nations: Australia, Canada, France, Germany, Greece, Ireland, Italy, New Zealand, Norway, Poland, Portugal, Singapore, Spain, Switzerland, UK, and USA:


Frédéric, Laurence, Jillian, Christine, Kate, Sacha, Joanna, Ellis, Ann, Nathalie, Khai Lin, Amanda, Valentina, Rachel, Iris, Graham, Joy, Chrystelle, Lisbet, Katrine, Cornelia, Kate, Jamie, Dagmar, Chloe, Allan, Marie-Eve, Merry, Aislinn, Siobhan, Mirjam, Laura, Riccardo, Dominique, Emily, Karen, Jakub, Valentina, Christina, Russell, Gabriella, Dimitiros, Claudia, Nicole, Andrea, Frédéric, Alison, Suzanne, Marta, Nathan, Steven, Laura, Beatrice, Kathryn, Joana, Ana Caterina, Philipp, Lydia, Yasmine, Gabriele, Lois, Pierandrea, and Jennifer (in order of participation).

Silvia and the Hellenic Dolphins team 2010

The Comfort of Others

Searching for dolphins in a rough sea can often be a frustrating activity for a cetacean researcher, with every wave and white-cap a constant source of distraction. At some point, however, the reward for hours of concentration can be presented before you, as the research team in the Gulf of Corinth found yesterday morning. At the sudden appearance of an unusually large dorsal fin, I progressed through a process of alarm, confusion, and eventual enlightenment as the Principal Investigator, Silvia Bonizzoni, began to emit ultrasonic squeaks, bouncing up and down behind the steering wheel.  We had chanced upon a sighting of the elusive Risso’s dolphin! 

Sightings of Risso’s dolphin are hardly common in the Gulf of Corinth – researchers at the Pelagos Cetacean Research Institute of Greece have documented only two individuals in the entire area. The Tethys team themselves have spotted this species only once prior to today’s sighting, identified subsequently as the same individual sighted yesterday. Thus it is perhaps understandable that professionality climbed out of the boat and swam off for the initial few minutes of the sighting, as Silvia and I proceeded to jump about the boat, exclaiming in barely-restrained elation.

Observing this magnificent creature, even for a short period of time, reveals the true extent of their behavioural complexity. Throughout the duration of the sighting, this large dolphin was exhibiting what could only be described as ‘play’ behaviour, nosing up underneath a Cotylorhiza jellyfish, flipping it back and forth between caudal and dorsal fin. The true purpose behind this activity is unknown - due to our regrettable inability to communicate with the individual – however, it may be theorised that this behaviour arises as a result of social exclusion from its own kind, or simply a reflection of the complex ‘personality’ traits exhibited by higher order mammals in this way. However anthropomorphic it may seem, the Risso’s was visibly enjoying itself, albeit to the extent of the unfortunate jellyfish.

The most striking point of interest taken from this sighting was the presence of the single Risso’s dolphin amongst a mixed group of striped and common dolphins. The astoundingly high level of interaction between the Risso’s and the other dolphin species indicated how deeply integrated the individual has become. Gliding side by side, the striped, common and Risso’s dolphins give a lesson in the achievement of peaceful co-habitation.

Border disputes and territory skirmishes mean nothing to these animals, as newborn striped dolphins hurtle themselves across the water surface in and around the larger un-related animal. The trust exhibited by the striped and common dolphins towards the Risso’s – in tight formation for the majority of the sighting - leaves the observer incredulous. The individual exhibited apparent protective behaviour over the smaller dolphins - encircling the boat, remaining in a constant shielding position between our vessel and the focal group. The animal maintained an aura of both dominance and care, ensuring the safety and security of those individuals that have welcomed it into their social network in the absence of its own kind.

What struck my pensive mind during the sighting was the juxtaposition of this inter-specific trust and integration, with the equivalent human context above the sea. We humans instigate whole dossiers of law and legislation before any form if immigration program can be established in a country. In our world, sociality is often divided by race, religion, borders and resources. Life for us is to be fought, not shared. The marine mammal microcosmos, however, is apparently untouched by such forms of division. Whilst our people are torn apart by petty disputes, these animals have found a way to co-exist and benefit from that which is necessary to all living creatures – the comfort of others.

Philippa Dell

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Relevant literature:

Frantzis A., Herzing D. 2002. Mixed-species associations of striped dolphins (Stenella coeruleoalba), short beaked common dolphins (Delphinus delphis) and Risso’s dolphins (Grampus griseus) in the Gulf of Corinth (Greece, Mediterranean Sea). Aquatic Mammals 28(2):188-197.

Ionian Dolphin Project: updated report 1991-2009

The Ionian Dolphin Project, a long-term research and conservation programme conducted by Tethys in the eastern Ionian Sea, has recently completed a report of the activities done in the context of its three study areas in Greece: Gulf of Amvrakikos, Gulf of Corinth and Inner Ionian Sea Archipelago.

The online version of the report can be viewed at the link below:

http://www.tethys.org/hd/research.htm

(also see pages of the Menu)

Enjoy!

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NOTE:
the links above have been updated since the web site was modified in August 2010.

Gulf of Corinth: the 2009 research season ends

The Ionian Dolphin Project in the Gulf of Corinth has recently concluded its first research season, with a total of 58 dolphin sightings.

We are happy about the work done in 2009, and we would like to thank all the 66 volunteers who participated in the Delphi’s Dolphins field courses and helped us with the research.

Participants in our dolphin research programme came from 18 different countries: Australia, Belgium, Bulgaria, Canada, China, France, Germany, Greece, Hungary, Indonesia, Ireland, Israel, Italy, Lithuania, The Netherlands, Russia, UK, and USA.

A big THANK YOU to our volunteers:
Gunda, William, Ramona, Dagmar, Hermann, Clara, Tony, Peter, Jacqueline, Luke, Aimee, Dipti, Agnes, Julia, Eddie, Hilary, Juliette, Zuzana, Emilie, Rebecca, Emilie, Neysa, Emma, Susan, Elektra, Cate, Katherine, Sara, Heather, Catherine, Delphine, Ana, Julja, Jenny, Rebecca, Russell, Hannah, Amie, Kelly, Petra, Felicity, Christian, Roberta, Nadine, Jacqueline, Julia, Grace, Odile, Alice, Gaelle, Catherine, Yvette, Anthony, Elisabetta, Paul, Helen, Jade, Dora, Orsolya, Victoria, Levanna, Ellie, Alyssa, Tracy, Joanne, and Esther (*).

The IDP staff 2009:
Silvia, Stefano, Joan, Susie, Aina, Tilen, Giovanni

(*): in order of participation

Pira on holidays

Pira is a male bottlenose dolphin who has been seen regularly around the island of Kalamos, Greece, for 15 consecutive years. He has been there since 1993 and is considered one of the most resident dolphins.

In April 2009 we spotted him in the Bay of Itea, Gulf of Corinth, where Tethys has recently started a new reserch project. To get there, Pira had travelled approximately 170 km.

After April, we did not manage to find Pira again despite extensive surveys in the central Gulf of Corinth. We started making jokes such as ‘Maybe Pira came here on holidays and now he is back in Kalamos’. Well... he was! In July and September he was seen again around Kalamos together with his old bottlenose dolphin friends. He had made a 170 km round trip along the Ionian coast of Greece.

Silvia Bonizzoni

Old friends sighted around Kalamos

A few days ago, two V.I.D. (Very Important Dolphins) were encountered around the island Kalamos: Pira and Spiti, both bottlenose dolphins, seen together in a group of 11 individuals.

In 2006 Pira, a male, had a piece of yellow fishing net stuck in his blowhole, but by July 2009 he had managed to extrude the net from the blowhole. During the September sighting, Pira went to bowride in front of our research boat and Joan Gonzalvo took some nice photos of the blowhole, confirming that the net went away without causing any visible problem.

Spiti is the most popular dolphin among volunteers who had a chance to see this dolphins around Kalamos, thanks to his distinctive non-fin. Spiti's dorsal fin has been cut-off (possibly by a longline or a boat propeller) in 2003. Despite the dramatic amputation, Spiti recovered well and pigmentation went back to the original dark grey color.

Silvia Bonizzoni

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Top photo: Pira bowriding our research boat
Bottom photo: Spiti with his missing dorsal fin

Ionian Dolphin Project web update

The web site section of the Ionian Dolphin Project has been updated to include work conducted until July 2009.

Check it out!

http://www.tethys.org/projects/IDP/

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The Ionian Dolphin Project is a long-term research and conservation programme conducted by the Tethys Research Institute in the Ionian Sea.

In 1991 the Tethys Research Institute started a study around the island of Kalamos, in the Inner Ionian Sea Archipelago (a Natura 2000 area). Initially meant to be a long-term investigation on the ecology and behaviour of common dolphins in a central Mediterranean hotspot, the study documented their sharp decline. Common dolphins declined dramatically from about 150 to 15 animals between 1995 and 2007. Actions by Tethys aim to facilitate their recovery. Bottlenose dolphins are found in the same area in relatively small numbers, but have stable trends and were studied intensively over the past decade. Ongoing monitoring allows to detect changes in population status and propose timely management measures.

In 2001 Tethys started a study in the Amvrakikos Gulf, where bottlenose dolphins are the only cetacean species encountered. This study showed that about 150 dolphins live in the Gulf. These dolphins are members of a resident community showing unique behaviour and ecology. The Gulf - which is part of a larger National Park - is also inhabited by loggerhead sea turtles Caretta caretta and has a rich bird fauna including rare species. Research carried out by Tethys is documenting how the local dolphin community interacts with its environment and how human activities - particularly fishing and pollution - may influence its conservation status.

In 2009 Tethys started a new study in the Gulf of Corinth to investigate the ecology and status of three cetacean species: bottlenose dolphins, striped dolphins and short-beaked common dolphins. Although the number of striped dolphins living in the Gulf is still unknown, concerns over their status are raised by their likely small population size, high degree of geographic isolation, reproductive closeness and limited extent of occurrence. Striped dolphins in the Gulf are often associated with a few common dolphins and inbreeding between the two species may occur. Bottlenose dolphins also live in the Gulf at low densities.

Research by Tethys is providing support to management efforts in the eastern Ionian Sea, through actions including:

- continued monitoring of dolphin groups through field research methods including boat surveys and individual photo-identification, to detect population trends, identify critical habitat, and gain further insight into ways of mitigating the present threats;

- research on factors threatening the local ecosystem, particularly with regard to the impact of fishing;

- public awareness initiatives (e.g. involvement of a large number of volunteers, “Dolphin Days” and other events organized locally, public presentations, lectures at local schools, video productions);

- contacts and meetings with the local Authorities and fishermen organisations, aimed to a) raise awareness on the need to establish measures to protect dolphins and implement the existing regulations (e.g. with regard to illegal fishing activities); and b) identify ways to compensate any losses for fishermen or promote a progressive re-conversion of their activities;

- dissemination of information in the scientific literature and provision of sound data and management proposals to international agreements and bodies concerned with the protection of marine biodiversity.

Curley the striped dolphin

Dolphins sometimes have rather strange dorsal fins.

The curled dorsal fin of this striped dolphin (click on photo to enlarge) was photographed in the Gulf of Corinth, Greece, in the context of Tethys' Ionian Dolphin Project.

Physical anomalies are not so uncommon in the Gulf of Corinth, and have been observed on both striped dolphins and bottlenose dolphins.

This particular individual has been nicknamed 'Curley'. We do not know what may have caused this deformity. In any case, Curley looked as fit as any other dolphin in the group.

GB

All good things come to an end

Isn’t it strange how six weeks sometimes feel like a small eternity? That’s at least the impression I have as my time here in Amvrakikos Gulf is drawing to an end. Once immersed in the pleasant routine of combined field and analytic work, everything else fades away and you feel like you have been here forever. Although a cliché, it wouldn’t be an exaggeration to say that this experience has paved the road for a new chapter in my life.

Professionally, I have learnt and developed tremendously, and have no doubt that this is my ‘path in life’ (to throw in another cliché). Personally, I have had a lot of fun and enjoyed every day out at sea. ‘Conservationally’, I hope that my work will make some kind of contribution to cetacean research.

On my last day we also made a second survey of the site of Kalamos, and the comparison with Amvrakikos is rather striking. This place looks like a paradise, but is unfortunately a paradise in decline, for dolphin-lovers at least. Listening to Joan describing the situation of 10 years ago, it is difficult to believe that hardly any cetaceans or marine mega fauna remain.

Being able to follow your beliefs and passions as part of your work is a privileged few are entitled. I thus feel doubly grateful for having had the opportunity to work with Tethys as a research assistant. A special thanks is due to Joan and Giovanni, whose guidance and support have made my time here not only possible but also challenging and exciting. Bon courage for next week Joan!

Christina Geijer

First survey of the year at Kalamos

On June 8th, we carried out the first survey of the year in the area of Kalamos. It felt good to navigate these waters, where I had my first dolphin sighting ten years ago, after four years without personally doing any survey in this area.

However, no dolphins were spotted across more than 3 hours of survey under good sea state conditions. This was no surprise, considering the negative dolphin population trends that we have been describing over the years.

During the survey, countless anecdotes about the numerous sightings I had in these crystal-clear waters came to mind. It is hard to believe that an area that was so full of marine life just a decade ago has become such a desert. Surveying the area of Kalamos will help us keep in mind that bottlenose dolphin abundance in the Amvrakikos Gulf cannot be given for granted. Dolphins can and sometimes do decline in relatively short periods of time, and we must ensure that those we are studying in the Gulf won’t face the kind of anthropogenic impact that affected the area of Kalamos, former common dolphin paradise.

Joan Gonzalvo

What is a dolphin 'group'?

That group-living animals mainly exist in groups is pretty straightforward. What is less straightforward is how to define what constitutes a group, particularly for elusive and socially intelligent creatures like bottlenose dolphins.

In areas of high dolphin densities - like the Amvrakikos Gulf - it is common to see plenty of dolphins spread around the boat at various distances. Should all of these individuals be categorised as a single group, even though it is virtually impossible to count those further away? Or should you set a radial boundary with your boat as a reference point and only regard those individuals that move within that circle as a group? Or maybe solely count those animals engaged in the same behaviour? And surely, shouldn’t there be a standardised methodology of how to define a group across research sites? These are some of the questions I am trying to clarify and answer in the context of my Master thesis here in the Amvrakikos Gulf.

Each day that Joan, the volunteers and I venture out in the Gulf I count the dolphins according to different group definitions. The immediate aim is to analyse the discrepancy in group size estimates that they might yield, as well as determine which definition is most appropriate for the Amvrakikos Gulf. The overarching objective is also to bring attention to the conservation and ecological (etc.) importance of using a standardised group size definition, and come up with a suggestion of what such a methodology might entail.

Theoretically it might seem like an easy job, but the field is a different empirical matter. After two weeks of field work, my experience is this - in nature, things are often more intricate and complex than what they appear at first glance, and on philosophical days I’m inclined to agree with Socrates ‘all I know is that I know nothing‘. But, to me that’s also the charm about research - it’s challenging and requires complete immersion of all your faculties. And of course, the curiosity involved in not being able to predict where an experiment might take you.

Christina Geijer

Narrow Bay Hotel

Yesterday there had been no dolphin sightings and although the overall team spirit was high, on our way back from the supermarket Silvia and I decided to search for bottlenose dolphins from the coastal road, stopping our car from time to time to explore portions of sea.

The surface of the Gulf of Corinth was flat but we couldn't manage to spot any dorsal fin. As a last attempt, we parked on a cliff overlooking a coastal fish farm. It only took a second for Silvia to spot a minuscule dorsal fin in between the fish cages, about one km away.

Although the late afternoon was an unusual time to set up a dolphin survey, we called Tilen at the field station, and we told him to hurry up and get to that place with the boat right away, while Silvia and I were trying try to keep track of the dolphin. Our five volunteers were cooking and showering by then, not expecting such a sudden change in the programme, but they reacted promptly and in a minute they were ready to go. It didn't take long to see the inflatable appear from behind a rocky cape and find the dolphin following the directions we gave from land.

In the meantime the dolphin had left the fish farm and approached the place were we had parked, eventually entering a narrow fjord where he started feeding quietly under our amazed eyes, only a few metres from the coast. Tilen approached very carefully and the dolphin did not react or change his behaviour at all. This was one of the rare occasions when one could tell whether our work causes any behavioural disruption. In this particular case, it was obvious that the dolphin couldn't care less about our inflatable, as confirmed by the respiration intervals that Silvia was recording with her digital watch throughout the observation.

The dolphin went on feeding in the narrow bay for about an hour, moving in circles and performing short dives of about 1.5 min. Then he probably decided that dinner was over (it was around 8 PM) and he moved to the other side of the bay, spending the next hour resting about 10 m from the rocky coast.

At 9 PM the light was rapidly fading and we decided to stop the observation so that the team on board could get back to the port before darkness. The dolphin, however, looked like he was going to spend the whole night at Narrow Bay Hotel.

Giovanni Bearzi

Our first striped dolphins off Galaxidi

Yesterday has been a special day: my first striped dolphin (Stenella coeruleoalba) sighting ever, and the first sighting of this species for the Ionian Dolphin Project in the Gulf of Corinth.

I was out at sea with Tilen Genov and five volunteers. The sea was a little choppy but expectations were high, as the day before we had seen no dolphins. Any buoy, bird or strange wave looking like a dorsal fin caused a little jump into my stomach, but after 30 min we spotted three small fins.

The animals were far from us and I was quite sure they were bottlenose dolphins, as until that moment we had only seen this species, including in that particular area. But as soon as we approached them we could see the distinctive white flanks: striped dolphins!

It was a small group of only three adults, performing short dives in a very quiet way. They were probably resting and didn’t perform aerial behaviour.

Coordination on board was great, and we managed to collect a lot of data. At the end of the sighting, everybody was satisfied about this unexpected encounter and the work we did. We went back to the field station in Galaxidi on the same choppy sea that had opened the day, and immediately downloaded the digital photos: one dorsal fin had distinctive notches, one a small nick, and the third wore no markings at all.

Our striped dolphin photo-identification catalogue had started.

Silvia Bonizzoni

Bottlenose dolphin carrying dead newborn

Gulf of Corinth, 18 May 2009

An adult bottlenose dolphin was observed carrying a decomposed newborn, possibly her dead offspring.

The observation was made by Tethys researcher Silvia Bonizzoni and by Tilen Genov, President of the Slovenian NGO Morigenos, together with four volunteers participating in the Ionian Dolphin Project.

The presumed mother was observed for a total of two hours, consistently carrying the corpse on her back, in front of the dorsal fin (see photo), also performing dives and resurfacing with the newborn. Occasionally the dead newborn was pushed and carried underwater by her presumed mother with the rostrum.

Other dolphins were seen in the area during the observation, but they tended to stay away from the couple.

The presumed mother was photo-identified based on long-term natural marks on her dorsal fin. On the following day (19 May) she was sighted again in the same area in the company of another adult, but without the dead newborn.

Giovanni Bearzi

Life goes on for "super-mama"

Amvrakikos Gulf, 22 May 2009

Today we saw a very special friend. I was happy to see a female bottlenose dolphin very well know to us. Her photoidentification code in our catalogue is 03046, but since July 2007 I keep referring to her as “super-mama” (super-mom). During the 3rd and 4th of July 2007 we observed her mourning a dead newborn, likely her own offspring.

Our last encounter was on December 2008. This morning we saw her in close association with another newborn. There were three other newborns/calves in that group. Next sightings will confirm whether or not she is the actual mother of the newborn she was swimming with.

Joan Gonzalvo

Newborns!

Today we saw the first newborns of the 2009 research season in the Amvrakikos Gulf.

What initially started as a sighting of a single individual quickly evolved into one that will stay in our retinas for quite a while.

After about half an hour with this new group, we were amazed to see two newborns approaching our boat up to a few metres.

Aina, our Catalan research assistant, was especially happy. Finally, today, on her last day in Amvrakikos until next September, she was the one who spotted the group!

As I write these lines, Aina is on her way back to Barcelona. I am sure that she still has a smile on her face while recalling the images of this morning.

Newborns are always good news. Their immature way of swimming, surfacing with their chins up besides their mothers, and their foetal creases on both sides giving them a zebra-like appearance, filled us with joy and optimism.

Joan Gonzalvo

Amvrakikos Gulf: first sightings of the year

The season of the ‘Dolphins of Greece’ project has recently started and it seems to be another promising one.

Just as a way to get started, Joan Gonzalvo, the principal investigator, spotted three bottlenose dolphins from the seafront while he was walking with his dog Posi.

Then, despite the unfavourable weather, the first team of Earthwatch volunteers made three sightings in a row, immediately recognising three old friends: ‘Helikas’ (a highly marked dolphin with a big notch behind her dorsal fin), ‘Koboloi’ (a bossy dolphin who likes to show off), and ‘Max’ (a very active and playful female).

And then not only dolphins… the lucky team also met two rare Dalmatian pelicans (Pelecanus crispus).

Definitely an excellent start!

Silvia Bonizzoni

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For more information:
http://www.tethys.org
http://www.earthwatch.org

Amvrakikos Gulf: new photo-identification data

The research project ‘Dolphins of Greece’, conducted by Tethys in the Amvrakikos Gulf, has recently completed the analysis of photo-identification data pertinent to the whole 2008.

A total of 3,818 selected digital photos, obtained from January to December during sightings along survey transects that cover the whole gulf, allowed to photo-identify 115 individual bottlenose dolphins.

Most of these recognizable individuals are well-known and were already present in the catalogue started in 2001 , but four of them are new animals never seen before.

Ten of the 115 dolphins were sighted together with immature individuals (newborns, calves or juveniles) and this looks like a promising sign for this highly-resident population that lives in a semi-closed eutrophic gulf.

Photographs included a number of non-identifiable animals, i.e. individuals carrying no distinctive marks on their dorsal fins. These, as well as all the subadult classes, should be added to the number of animals sighted in 2008. So, at present, it appears that the total number of animals seen in the Gulf last year is consistent with the population estimate of 150 made in previous years (Bearzi et al. 2008).

Ongoing monitoring will allow researchers to gain insight into the ecology and trends of this unique bottlenose dolphin community.

Silvia Bonizzoni

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For more information:
Bearzi G., Agazzi S., Bonizzoni S., Costa M., Azzellino A. 2008. Dolphins in a bottle: abundance, residency patterns and conservation of bottlenose dolphins Tursiops truncatus in the semi-closed eutrophic Amvrakikos Gulf, Greece. Aquatic Conservation: Marine and Freshwater Ecosystems 18(2):130-146.

http://www.tethys.org/projects/IDP