Scottish Marine Animal Stranding Scheme

The majority of seals that were examined by SAC were in the latter stages of pregnancy. There were also two young seals that could have still been learning to feed.

I am confident that we have to be looking for some type of ducted propeller/impeller that has not been used in this area previously, especially around the time of year when seals are heavily pregnant. The idea of these injuries being caused by sharks should be discounted. Even if sharks large enough to attack adult seals were found in waters off the east Coast of Scotland, and they are not, shark attacks would not leave the type of lesions that we are seeing on these carcases.

It is possible that pregnant seals and young seals are being attracted to the vicinity of these impellers by dead fish that are also being killed by the same devices or by shock waves caused by pile-driving by the vessel that is using the impellers. Freshly dead fish to eat without expending effort in catching and killing them might seem like an attractive proposition.

If we assume that these impeller/thrusters devices are linked to a GPS system and are used to keep a vessel in position then they would be constantly starting and stopping and if one was switched on while a seal was very close by, especially a heavily pregnant one it could easily be sucked into the mechanism causing the injuries described.