A disabled fin whale that has become a mascot for a marine sanctuary in the Mediterranean has suffered a second disaster. Already missing half its tail after a collision with a ship, it has now lost the other half, possibly following another impact, or after getting caught in fishing line.
Strikes by ships and entanglement in fishing gear are the leading threats to whale populations globally, according to a .
Fin whales are the world鈥檚 second-largest animal after the blue whale, but the tailless one is emaciated. 鈥淚t wanders around the Mediterranean more and more weakened, missing the organ that usually guarantees propulsion,鈥� says Maddalena Jahoda at the , a marine mammal conservation organisation based in Italy. 鈥淚t seems unable to dive and therefore feed.鈥�
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Jahoda first spotted the animal in 2005, and named it Codamozza (鈥渃ut-off flukes鈥�) after noticing it appear to 鈥渓imp鈥�. Fin whales don鈥檛 usually raise their tails, or flukes, above the water when they dive, but this one did, probably because it was having trouble propelling itself down.
Recent sightings
Last October, several researchers reported sighting a fin whale with no tail off the coast of Spain and France, then it was seen in Syrian and Greek waters. On 14 June, it was spotted in the busy waters of the Strait of Messina, the narrow stretch between Italy and Sicily, and photographic records allowed Jahoda to identify it as Codamozza. The Italian coastguard escorted the animal into the open ocean to prevent any collisions with ferries, and on 22 June, it was seen in the waters of the , an 87,500-square-kilometre area of water between Monaco, France and Italy.
鈥淭he sanctuary is the typical summer feeding ground for fin whales, rich in Mediterranean krill,鈥� says Jahoda. 鈥淪o 鈥� maybe 鈥� we hope it will be able to feed.鈥� The IWC report lists the Pelagos sanctuary as a high-risk area for whale-ship collisions.
Codamozza can swim quite fast, despite the impairment, but tends to stay on or near the surface, and researchers are worried it can鈥檛 feed. Fin whales feed by diving into prey 鈥� krill and small fish 鈥� with their mouths open, scooping huge amounts of water. But Codamozza may be unable to generate the thrust required to feed properly.
As shipping traffic increases, so too does the risk for whales. Noises from ships travel many kilometres underwater, bouncing off the sea bed and sea surface. 鈥淭his produces complex and multiple echoes,鈥� says Philippe Blondel at the University of Bath, UK. 鈥淚f the source is moving fast, for example a ferry, it will be even more difficult to understand where it is.鈥� It is why whales often may not hear a big ship coming towards them.
Blondel is working with his mathematician colleague Chris Budd to find a way to detect whales from the complex mass of sonar readings, and so help ships avoid them.
鈥淪hips and whales do not mix,鈥� says Budd. 鈥淲hales are big, but ships are bigger, and the whale usually comes off worse in a collision. By using maths, we can help to locate the whales from these sounds and this makes the ocean a safer place for them to live in.鈥�
