Apulia Dolphin Project, Italy

Cetacean strandings in the District of Brindisi, Italy, southern Adriatic Sea

January 2002 - May 2008 (ongoing)

Paola Pino d’Astore (1), Giovanni Bearzi (2), Silvia Bonizzoni (2)

(1) Biologist, private address, Brindisi, Italy
(2) Tethys Research Institute, Viale G.B. Gadio 2, 20121 Milano, Italy

See phototographic documentation of strandings Warning images portray dead, amputated and/or decomposing animals and may be disturbing to some.

Summary

Relatively little is known about the cetacean fauna inhabiting the southern Adriatic Sea. Cetacean strandings therefore represent an important source of information to gain insight on the species inhabiting these waters.

Between January 2002 and May 2008, a total of 46 cetacean stranding events were recorded in the Province of Brindisi, on the south-eastern coast of Apulia, Italy, over approximately 100 km of coastline.

Strandings were always of single individuals and included 2 Cuvier’s beaked whale Ziphius cavirostris, 16 common bottlenose dolphins Tursiops truncatus, 9 striped dolphins Stenella coeruleoalba, 4 small Delphinidae (most likely S. coeruleoalba), 11 small Delphinidae, and 4 unknown cetacean species.

This dataset complements information recorded by the Italian Centre for Cetacean Studies since 1986, confirming that common bottlenose dolphins and striped dolphins are the species predominantly found stranded in the Province of Brindisi.

The two findings of Cuvier’s beaked whale are new to the record for the Province of Brindisi. The first animal was found on February 22nd, 2003, with its rear part possibly cut off by a ship’s propeller. The second stranded on July 6th, 2003.

Absence of confirmed records of short-beaked common dolphins Delphinus delphis corroborates that the species is either rare or absent in this part of the Mediterranean Sea.

Materials and methods

The study area is located in the southern Adriatic Sea, on the south-eastern coast of Apulia, Italy. Monitoring effort uniformly covered the whole Province of Brindisi, between Torre Egnazia and Lendinuso, totalling approximately 100 km of coastline (Fig. 1).

This area includes both rocky and sandy shores. It is a highly patrolled portion of the Italian coast where strandings of cetaceans and other marine megafauna can hardly go unnoticed, regardless of the season. Year-round coverage of the study area was granted by an information network established by the first author, including local Authorities, veterinarian officers, private citizens and a number of other collaborators (see Acknowledgements) who have been providing timely reports over the years.

Information collected was carefully scrutinized to eliminate reporting biases. Species identification was based on photographic documentation and other clear-cut evidence. Uncertainty in species identification resulted in cautionary rather than unwarranted attributions. However, identification only took into account species known to occur in the Mediterranean Sea.

Uncertainty involved primarily small dolphins (200 cm TL or less) in advanced decomposition, having a rostrum and about 35-50 teeth in each jaw. These could be either striped dolphins Stenella coeruleoalba or short-beaked common dolphins Delphinus delphis. As the latter species was never found stranded in the Province of Brindisi and has declined dramatically in central Mediterranean waters, uncertain species with the attributes mentioned above were classified as “small Delphinidae (most likely S. coeruleoalba)”. If information about key identification features was absent, dolphin-like carcasses were classified as “small Delphinidae”. Body length was not considered as a reliable feature to discriminate between the two categories above, considering that a small carcass could also be of a young common bottlenose dolphin Tursiops truncatus specimen.

Study area with the location of 46 cetacean strandings recorded between January 2002 and May 2008.
The location of the Province of Brindisi relative to Italy is shown in the inset.

Relative distribution of cetacean strandings by species.
Zc = Ziphius cavirostris, Tt = Tursiops truncatus, Sc = Stenella coeruleoalba,
SmallDelph (Sc) = small Delphinidae (most likely S. coeruleoalba), SmallDelph = small Delphinidae.

Relative annual distribution of cetacean strandings by species.
The “(2008)”bar indicates the percentage of strandings recorded between January and May 2008.

Number of cetacean strandings by year. While years 2002-2007 refer to a 12-month annual coverage (January-December), the “(2008)” bar indicates the number of strandings recorded during 5 months (January-May).

Number of cetacean strandings by month.

Acknowledgements

Paola Pino d'Astore is grateful to the local authorities involved in this study: Capitaneria di Porto of Brindisi; Comando Provinciale dei Vigili del Fuoco of Brindisi and their Nucleo Sommozzatori; Polizia Municipale of the Brindisi Province's coastal Municipalities; Comando Provinciale dei Carabinieri of Brindisi; Polizia di Stato and its Squadra Nautica; Marina Militare Italiana; Protezione Civile; Provincia di Brindisi. I am grateful to Giacomo Baccaro and everybody at the Consorzio Area Marina Protetta of Torre Guaceto for reporting several stranding events. Thanks to the Servizio Veterinario of the Brindisi Local Sanitary Unit (ASL BR01) and to Prof. Nicola Zizzo, Department of Pathological Anatomy, Faculty of Veterinary Medicine, University of Bari. Thanks to all the private individuals who kindly reported the strandings and to all those who helped during the inspections. Finally, Paola is grateful to her daughter Sveva for her patience and for being such an excellent collaborator during inspections of stranded animals.

Other information on cetacean strandings in the District of Brindisi

The information reported above represents a new and unpublished contribution.

More cetacean strandings in the District of Brindisi have been recorded by the 'Centro Studi Cetacei' and are included in the Italian Stranding Data Bank. A synthesis of the available information is given in Fig. 6 for comparative purposes. More detailed information can be obtained from the Stranding Data Bank.

Most strandings in this dataset involve striped dolphins recorded during the extended mortality that affected this species in 1991.

Fig. 6. Cetacean strandings in the District of Brindisi (1986-2003), recorded by the 'Centro Studi Cetacei'
and included in the Italian Stranding Data Bank .

The large number of striped dolphin strandings recorded in 1991 relate to mass mortality in that year, occurred over large portions of the Mediterranean region and predominantly affecting this species.

The unknown cetacean stranded in Torchiarolo on 12 June 2003 is not included in the 2002-2008 dataset by Pino d'Astore et al.

Additional information can be found in the following scientific publication:

Pino d'Astore P., Bearzi G., Bonizzoni S. 2008. Cetacean strandings in the Province of Brindisi, Italy, southern Adriatic Sea. Annales, Series Historia Naturalis 18(1):29-38. (1.2 Mb)