The Synoptic Ferry Observation Network project recorded 707 sightings of marine megafauna between June and July. Researchers from the University of Barcelona used commercial ferries to track whales and dolphins across the Mediterranean. They found that species like fin whales move between marine areas in a remarkably short time.
Where are the great marine animals of the Mediterranean, such as the fin whale, the sperm whale or the bottlenose dolphin? How does their distribution change over a few weeks? All indications suggest that these species shift between marine areas in a remarkably short time and over relatively small spatial scales. Some species, such as the striped dolphin, maintain a relatively stable presence in certain areas, while others, such as the fin whale, move and concentrate in different areas from one observation campaign to the next.
These are some of the main conclusions of the Synoptic Ferry Observation Network (SYNFONY) project, an initiative to monitor marine megafauna in the Mediterranean with the support of ferry lines and shipping companies.
As part of the project, professors Odei Garcia-Garin and Manel Gazo of the Faculty of Biology and the Biodiversity Research Institute (IRBio) at the University of Barcelona coordinate observations along the Barcelona–Tangier–Barcelona route. More than 20 volunteers have also taken part in the project, mainly students in the UB's degree programs in biology, marine sciences and environmental sciences.
A total of 707 sightings of marine megafauna
Between June and July, three scientific campaigns recorded 707 observations of marine megafauna, mainly of the eight cetacean species commonly present in the Mediterranean: the fin whale (Balaenoptera physalus), the sperm whale (Physeter macrocephalus), Cuvier's beaked whale (Ziphius cavirostris), the common dolphin (Delphinus delphis), the bottlenose dolphin (Tursiops truncatus), the striped dolphin (Stenella coeruleoalba), Risso's dolphin (Grampus griseus) and the long-finned pilot whale (Globicephala melas).
Two sea turtle species were also recorded: the loggerhead sea turtle (Caretta caretta) and the green sea turtle (Chelonia mydas).
Observations along 19 fixed shipping routes in the western Mediterranean and the Adriatic provided a broad, simultaneous snapshot of the distribution of marine megafauna, particularly cetaceans and sea turtles. Commercial ferries thus become platforms for observing marine biodiversity, using the routes they regularly sail to gather data on the presence and distribution of species.
A distribution that changes in a few weeks
The striped dolphin offers one of the clearest examples. "During the first campaign it was observed more frequently and over a wider area. In the third campaign, however, the sightings were much more spatially concentrated, especially on one of the routes in the Spanish corridor," say Garcia-Garin and Gazo, from the UB's Department of Evolutionary Biology, Ecology and Environmental Sciences.
The fin whale showed a relatively stable number of sightings across the three campaigns. However, its distribution along the different routes changed considerably.
"Sea turtles also showed significant variability. The loggerhead turtle was the most frequently observed taxon across the entire monitoring period. However, the number of observations decreased from the first campaign to the subsequent ones, while changes in its distribution within the network of monitored routes were detected," the experts note.
SYNFONY is being developed as part of the Fixed Line Transect Mediterranean Monitoring Network (FLT Med Net), coordinated by the Italian Institute for Environmental Protection and Research (ISPRA), of which IRBio-UB has been a member for almost 10 years. This initiative draws on more than two decades of experience in collaboration with shipping companies.
Toward more dynamic risk management
Maritime traffic is one of the pressures that may overlap spatially and temporally with the presence of cetaceans and turtles. Data obtained by SYNFONY can help develop new dynamic risk assessment models that integrate the presence of species, the intensity of maritime traffic and environmental conditions within a single framework.
"The aim is to be able to identify more precisely which areas and which periods present a potentially increased risk to marine megafauna and to advance toward a better understanding and management of the Mediterranean marine space," the experts say.
"In this challenge, we must thank all the volunteers who, as observers on board, have made these campaigns possible, as well as the shipping companies and all the people and institutions who have contributed to the development of the project. Their participation and commitment are key to continuing to expand knowledge of Mediterranean marine biodiversity and advancing its conservation," conclude Garcia-Garin and Gazo.