Silurian Marketing Materials General Brief for Website | Page 7

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Looking for animals

Volunteers take it in turn to scan the sea for animals from the mast.

Along Silurian’s route, we also record the location of things that could affect the behavior of cetaceans, such as fish-farms, creels, floating litter and other boats.

Photo identification

We can identify individual animals from the unique markings on their bodies, particularly on their dorsal fin. When a photo is taken it is catalogued to help with future identification. By collecting photos of the same individual each year we learn about their movements, how long they live , if they produce calves and which other individuals they spend time with. It’s an exciting moment when a familiar animal is sighted!

Listening for animals

Behind Silurian we tow a hydrophone (underwater microphone) to pick up the sounds made by animals that are under the waves.

Noise pollution in the sea created by humans is also recorded, for example Acoustic Deterrent Devices that are used by many fish farms to scare seals. We are concerned that this noise could also affect cetaceans, particularly harbour porpoises. HWDT also monitors military acoustic exercises to see if the effects of sonar and explosives are harmful to cetaceans.

Why research matters

Until recently, remarkably little was known about the cetaceans found in Hebridean waters. Each year we learn more about the animals and their behaviour. By collecting data over a long period of time we can detect changes, such as a drop in animal numbers or a shift in distribution. This enables us to provide crucial information to international conservation groups and the Scottish Government, helping to protect the diverse marine life of the Hebrides.