First ever juvenile basking shark

Juvenile Basking Shark

We have some really exciting news in that one of our recent tours spotted our first-ever sighting of a juvenile basking shark. We believe this could be one of the only records of a juvenile in the Hebrides and certainly the only underwater image of one.
Our normal size class of basking sharks is between 3-8m, with the maximum size said to be 12m. The maximum we would see is around the 9-10m mark but the really big ones are rarely sighted. This could be for several reasons, such as hangover from the hunting during 40’s and 50’s or simply the larger ones are travelling to other places. The Hebrides are thought to be a breeding area due to the large aggregation of basking sharks here over summer and the behaviours that are seen here such as breaching and (potential) courtship. We did jointly publish a paper recently on basking shark behaviour where we found no connection between breaching and courtship but given the energy cost to the animal and the complexity of the behaviours there must be some link yet to be found. See an iphone video of basking sharks breaching here.

As there are very few records (if any) of juveniles then it is understood that this area is not a pupping ground. The location, number of pups, and the whole reproductive process are not understood in basking sharks or well described. There are small pieces of the puzzle adding to the mystery of this part of their life cycle. With the sole record of pupping by a Norwegian fisherman who unfortunately caught a basking shark, and spontaneously gave birth to one live and five dead pups.
The juvenile we watched was feeding at the surface and out of the interest scientifically – was very very cute! It was like the large basking sharks we see but in miniature and squashed into a small package! The one very distinct difference was the rostrum (or nose!) which lifts at the front, rather than being a full bulbous feature as the adults have.
We’re keen to write a full report on this once the main season has finished and will share this when it’s possible.
The picture below was from Stuart Holmes one of our clients on the tour. It was great for him to share the images with us and we believe they will provide a useful resource for further understanding of basking sharks by the scientific community.