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Research project data


Research subject/title:
Summer 2007 results of Changes in frequency of occurrence of cetaceans along a transect in the Central Tyrrhenian sea over 15 years.

Project coordinator / institution in charge:
Dr. Luca Marini/ Accademia del Leviatano

ACCOBAMS Priority number (VIEW):
4, 5

Project description:
Results from summer 2007 survey. Monitoring cetacean presence, distribution and migration timing is an effective indicator to detect environmental changes and habitat degradation. The geographical and ecological characteristics of the Central Tyrrhenian Sea makes it strategic for monitoring the presence of animals, also because intercepts the marine corridor that connects the Northern-Pelagos Sanctuary to the Southern-Mediterranean Sea. From 1989 to 1991 weekly observation on cetacean were undertaken from non-dedicated ferries along the “transect” from Civitavecchia (Rome district) to G.Aranci (Sardinia). In 2007 research restarted with same protocol and under supervision of same investigators. We compared summer data of the three years in the 1990’s (87 ferry runs with 590 hours of observations) with the study conducted from May to September 2007 (31 runs and 160h). Each transect was considered as an independent statistical unit and we primarily analysed frequency of occurrence (f.o.), mean group size (g.s.) and distribution. Results showed that in 2007 f.o. of Balaenoptera sp. was 0,18 h-1±0,06 with g.s. of 1,3±0,11 while, for Stenella coeruleoalba, was 0,51 h-1±0,08 with 5,4±0,57 g.s. There was a significant difference of monthly f.o. of Balaenoptera sp. (P<0.05), with higher values at beginning of summer, strengthening the migratory behaviour trend recorded for the first time in the 1990’s. Monthly f.o. of S. coeruleoalba, instead, was similar during the summer period in 2007 (P=0.36) as it was in the first study. Compared with 1990’s there was an increase of f.o. of Balaenoptera sp. (78%) and of S. coeruleoalba (29%), for the latter g.s. decreased (18%). Most of the sightings occurred towards the Sardinian coast. No ferry-whale collision was recorded in the investigated periods (n=139). Re-surveying confirmed how effective and cost efficient is such a programme for monitoring cetacean distribution and consequently environment quality. Increase abundance of animals and strengthening of migration pattern could be related to the Pelagos Cetacean Sanctuary supporting the need of the proposed new Sanctuary in the Southern-Mediterranean (Abstract at 22nd Annual Conference of the European Cetacean Society Egmond aan Zee, Netherlands, 10-12 March 2008)

Species:


  • Tursiops truncatus
  • Stenella coeruleoalba
  • Physeter macrocephalus
  • Grampus griseus
  • Delphinus delphis
  • Balaenoptera physalus
  • Balaenoptera acutorostrata

Study area:


Central Tyrrhenian Sea

Geographic Area:


  • Tyrrhenian Sea

ACCOBAMS subregion:


  • Central Mediterranean
Year beginning: 2007Year end: 2007

Ongoing project:


No

Main research platform/facility:


Principal investigator:


Luca Marini

Investigator email:


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Project team:


Antonella Arcangeli,
Andrea Poggi,
Alessia Poldi
Marina Pulcini,
Ricerche Ambientali e Biologiche http://www.crabcoop.it/
Universita’ della Tuscia di Viterbo