22 November 2010

Bottlenose dolphin movements 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.

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.

20 November 2010

Australian white sharks in the Mediterranean Sea

Some cetaceans and birds are known to perform long-distance movements. Now, a recent study explains how white sharks could also be added to this ‘record’ list. Researchers found out that white sharks living in the Mediterranean Sea are closely related to those living in Australian waters.

About 450,000 years ago, while some individuals were swimming between Australia and Africa, strong abnormal currents deviated their routes and probably led them to the west coast of Africa. Once there, they would have tried in vain to head east again to go back on their route but ended in the Mediterranean.

"Once they got to the Mediterranean they may have become trapped because its peninsulas and channels make it like a giant lobster pot (…) But because white shark females return to the area where give birth, once they birth in the Mediterranean they become a fixture, shaping and rebalancing the ecosystem" commented Jones, one of the authors.


---Image: ‘Bruce’ the white-shark in the famous cartoon ‘Finding Nemo’.

Gubili C., Bilgin R., Kalkan E., Karhan S.U., Jones C.S., Sims D.W., Kabasakal H., Martin A.P., Noble L.R. 2010. Antipodean white sharks on a Mediterranean walkabout? Historical dispersal leads to genetic discontinuity and an endangered anomalous population. Proceedings of the Royal Society B. 10.1098/rspb.2010.1856

ABSTRACT: The provenance of white sharks (Carcharodon carcharias) in the Mediterranean is both a conundrum and an important conservation issue. Considering this species's propensity for natal philopatry, any evidence that the Mediterranean stock has little or no contemporary immigration from the Atlantic would suggest that it is extraordinarily vulnerable. To address this issue we sequenced the mitochondrial control region of four rare Mediterranean white sharks. Unexpectedly, the juvenile sequences were identical although collected at different locations and times, showing little genetic differentiation from Indo-Pacific lineages, but strong separation from geographically closer Atlantic/western Indian Ocean haplotypes. Historical long-distance dispersal (probably a consequence of navigational error during past climatic oscillations) and potential founder effects are invoked to explain the anomalous relationships of this isolated ‘sink’ population, highlighting the present vulnerability of its nursery grounds.

For more information:

To read the paper:

08 November 2010

Sea turtles and plastic in the Adriatic Sea

A recent study conducted in the Adriatic waters focused on loggerhead sea turtle Caretta caretta and plastic debris.

Researchers from the University of Zagreb found that marine debris was ingested by 35% of loggerheads foraging in neritic habitats of the Adriatic Sea. Debris include plastic bags, wrapping foils, ropes, polystyrene foam and fishing line; but soft plastic was the most frequent found in digestive tract.

The high occurrence of debris intake represents a factor of concern for loggerheads in the Adriatic Sea. The researchers hope that, having shown that the turtles are particularly vulnerable to plastic debris, more will be done to reduce such debris.


Lazar B., Gračan R. 2010. Ingestion of marine debris by loggerhead sea turtles, Caretta caretta, in the Adriatic Sea. Marine Pollution Bulletin. doi:10.1016/j.marpolbul.2010.09.013

Abstract - We examined the occurrence of marine debris in the gastrointestinal tract of 54 loggerhead sea turtles (Caretta caretta) found stranded or incidentally captured dead by fisheries in the Adriatic Sea, with a curved carapace length of 25.0–79.2 cm. Marine debris was present in 35.2% of turtles and included soft plastic, ropes, Styrofoam and monofilament lines found in 68.4%, 42.1%, 15.8% and 5.3% of loggerheads that have ingested debris, respectively. The dry mass of debris per turtle was low, ranging from <0.01 to 0.71 g, and the ingestion was not significantly affected by sex or body size (all p > 0.05). Marine debris averaged 2.2 ± 8.0% of dry mass of gut content, with a maximum of 35% found in a juvenile turtle that most likely died due to debris ingestion. Considering the relatively high occurrence of debris intake and possible sub-lethal effects of even small quantities of marine debris, this can be an additional factor of concern for loggerheads in the Adriatic Sea.

06 November 2010

La nuova Tethys

Il 5 novembre si è svolta l'Assemblea dei Soci dell'Istituto Tethys durante la quale sono state rinnovate le cariche sociali di Presidente, Consiglio Direttivo e Collegio dei Probiviri.

Il nuovo Presidente è Giuseppe Notarbartolo di Sciara, mentre Simone Panigada è stato confermato Vicepresidente.

I membri del nuovo Consiglio Direttivo sono: Sabina Airoldi, Arianna Azzellino, Joan Gonzalvo, Giuseppe Notarbartolo di Sciara, Simone Panigada, Elena Politi e Margherita Zanardelli.

I membri del nuovo Collegio dei Probiviri sono Silvia Bonizzoni, Caterina Lanfredi e Massimo Demma, quest'ultimo in qualità di presidente del Collegio.

05 November 2010

Looting the seas

After 'The End of the Line', a powerful film has become available about one of the planet's most disturbing environmental problems - overfishing:

'Looting the Seas: how overfishing, fraud, and negligence plundered the majestic bluefin tuna'

This is a project of the International Consortium of Investigative Journalists. Its multinational team investigated into the bluefin trade for seven months scouring public records and interviewed sources in ten countries.

The documentary is composed by:

Overview - The Black Market in Bluefin. How a decade of rampant fraud and lax oversight threatened tuna stocks and created a $4 billion black market.

Part I - A Mediterranean feeding frenzy. How overfishing, rampant cheating, and official complicity plundered the Atlantic bluefin tuna

Part II - Diving into the tuna ranching industry. Sea "ranches” for fattening tuna became lucrative centers for “laundering” bluefin.

Part III - Bluefin, Inc. With no questions asked, Japanese traders fed a ravenous demand for high-quality sushi.

Not to be missed !


For more information:

04 November 2010

Il Mare Nero

Quella della Louisiana è forse la più grande catastrofe ambientale provocata dall'uomo nella storia. Nelle acque europee ci sono 100 piattaforme, in quelle del Mediterraneo ce ne sono un centinaio…

Così Milena Gabanelli - autrice e conduttrice del programma televisivo Report - ha introdotto la recente inchiesta 'Il Mare Nero'.

Dopo l’esplosione della piattaforma  BP nel Golfo del Messico sono fuoriusciti circa 5 milioni di barili, solo il 60% è stato recuperato o bruciato. In tanti si stanno chiedendo dove è finito? La risposta viene dall’Italia, e in particolare da un mare dove venti anni fa è colato tanto petrolio e i fondali non sono mai stati bonificati nonostante la legge sull’ambiente del ’98 lo imponesse…

Una puntata da non perdere, specialmente se si considera che nel Mar Ligure - ovvero nel cuore del Santuario dei Cetacei - nel 1991 è esplosa la petroliera Haven e le conseguenze, come sottolineato dal servizio di Sigfrido Ranucci, sono ancora evidenti.


Per maggiori informazioni:
'Il Mare Nero'

02 November 2010

‘Balloon head’ dolphin

New information about ancient cetaceans: a recent study identified an ancient dolphin characterised by a short, spoon-shaped high nose and a balloon-shaped forehead.

Platalearostrum hoekmani is its name: it lived 2-3 million years ago.

Only a bone has been found, but researchers are convinced they have discovered a new species, whose closest living relative is the pilot whale.

how Platalearostrum hoekmani probably looked, by R. Bakker / Manimal Works

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