In the Mediterranean, increasing numbers of finback whales, also known as rorqual whales, are colliding with marine vessels. In the Pelagos sanctuary, an area of protected waters stretching along the coast of France, Monaco and Italy, each whale encounters a boat 3520 times per year. As marine traffic increases, these mammals face a serious threat.

Torn or severed fins, as well as scars from the boats’ propellers… the aftermath of a collision is obvious. Despite being currently classed as “vulnerable” by the The International Union for Conservation of Nature (IUCN), marine traffic is certainly not careful around these creatures. In fact, colliding with a marine vessel is the most common cause of death, due to unnatural causes, for rorquals in the Mediterranean.

More traffic in Mediterranean waters

“Whales often die from the impact, so those who manage to survive that are the lucky ones” laments Simone Panigada, member of the Italian scientists’ committee at the UICN. As part of his research his studies the population density of finback whales in the Pelagos Sanctuary. Created in 1999, this maritime zone covers 87,500km2 of French, Monégasque and Italian coastline in an effort to protect mammals living there.

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Over the course of the past few years, Simone Panigada has noticed a net increase in marine traffic, resulting in a higher risk of collisions. “In the Mediterranean, many countries want to profit from the waters and are investing in ever more means of travel. Every summer, departing from Sardinia and Corsica, ferries bring tourists across the sea to the continent.”

Young whales most at risk

Between eight and 40 rorquals die every year due to these types of collisions. Denis Ody, Head of the WWF Cetacean Conservation Programme, explains how “this is a worrying number considering that the total population in the region is only around 1700.” As for their reproduction, “every female finback only gives birth to one offspring every two, sometimes even three, years.”

The majority of beached whales we find are only 14 metres in length, which is the size of a preadolescent rorqual.

In the Mediterranean, the rorqual population fluctuates based on the mortality of the younger whales, as these are the ones most likely to collide with a marine vessel. According to a member of WWF, ” the majority of beached whales we find are only 14 metres in length, which is the size of a preadolescent rorqual.”

Using GPS to locate cetaceans

In 2007, WWF started promoting a new system called REPCET. Described as a “sort of marine coyote” the system uses satellite communication to enable ships to share information about the presence of any cetaceans they have come across in the Pelagos Sanctuary.

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“REPCET has reduced the number of total collisions, but that is largely down to the crew members’ desire to help and their observation skills,” Denis Ody explains. However, for the past two years WWF has been working on a passive acoustic monitoring system. Although still only a prototype, it will one day be possible to use GPS to locate cetaceans in the Sanctuary based upon the sounds they emit.