The Aegean Sea is home to many cetaceans including the endangered Sperm whale (Physeter macrocephalus) during their migration patterns. I have been helping out with Marine mammal surveys which take place on the boat where I was extremely lucky to be part of a team that found sperm whales.

To locate the sperm whales we used a hydrophone, which can detect sounds from at least a ten mile radius. I got to listen to three sperm whales clicking whilst they were diving. The clicking sounds is where the whales are using echolocation, as they can echolocate for various reasons such as communication and for direction. On this account they were using echolocation because they were feeding. It was very exciting listening to the hydrophone as one minute the clicks were very fast, and then they would go into a slow rhythm and then silence. When it was silent, the sperm whales were ascending.

All together between the two observation boats, we saw 8-9 female sperm whales, including 1 calve just North of Ikaria. In particular two females came very close to the boat with a distance of 10 metres, they swam along the surface around the boat then one dived SW of the boat fluking its tail, half a minute later the second female dived again fluking her tail. It truly was magnificent.

Good photos were taken so now we need to identify individual species and the marine mammal team will see if they have been sighted in the area before. Also Sperm whales are known to be deep divers (800m to 1000m per avaerage) but where we saw them, the water was less than 500 metres deep so I have spent some time researching their shallowest dive recorded and I found that researchers found that the sperm whales were diving to depths of 150m to 300m just off the Galapagos Islands. They also found that they had regular clicks which are what we found when using the hydrophone. So I think this could be an interesting topic to look further into.

This entry was posted on Thursday, November 26th, 2009 at 9:29 am and is filed under Marine Team. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.