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Early September, as we were following a group of bottlenose dolphin in the Strait of Gibraltar, we saw a blow of a sperm whale. Immediately, we are changing course, as sperm whales are rarely present at this time of the year in the Strait. We are at 200 m from the animal: a ferry that crosses the Strait many times every day, enter in collision with the sperm whale. Soon after, the animal tries to dive and we see its caudal fin sectioned by the helical of the ferry. Closer to it, we notice at least two open wounds from which blood is running out. Many ribs are most probably broken. It blows blood for 30 minutes, takes a last breath and dies.

The corps continues to float and we then think that we should take advantage of this sad situation to learn more about sperm whales of the Strait. A necropsy would allow us to know exactly what they are eating in the Strait, to take pictures of its caudal fin to identify it clearly and compare it with our catalogue to know if we had already seen it, to assess its wounds and even maybe to understand why it did not react when the ferry arrived straight on it.

One of the reasons could be that it is deaf, like it has already been described for sperm whales that died due to collisions in the Canary Islands. This deafness could be due to a long exposition to very loud ambient noise, which we can easily imagine in the Strait of Gibraltar where the maritime traffic is the second highest in the world. This lost of an individual is very grave as until now we have counted only 16 to 18 individuals visiting the Strait to eat.

An interesting phenomenon happened right after the collision. More than 100 pilot whales of the Strait and a few bottlenose dolphins came around the sperm whale. These two species were very excited and were jumping, vocalising and slapping with their fins at the surface.

They stayed around until it was trawled out of the Strait where it was risking to enter in collision with other boats, unfortunately we could not do the necropsy. Indeed, no port gave us the permission to enter with the sperm whale. However, we did get a biopsy that will give us information on its sex, its alimentation and the level of organochlorines.