We have had an incredible start to the summer here at Manx Whale and Dolphin Watch on the Isle of Man with many sightings being reported to us, predominantly in the south of the island between Langness and the Calf of Man. We have in fact, had reports of all of our five key species in Manx waters, all reported during one week of each other. This includes Harbour porpoise Phocoena phocoena, Risso’s dolphin Grampus griseus, Short beaked common dolphin Delphinus delphis, Bottlenose dolphin Tursiops truncatus and Minke whale Balaenoptera acutorostrata. We have also had a possible Fin whale Balaenoptera physalus sighting.
This high frequency of sightings began in mid June with a number of Short beaked common dolphins reported close inshore, including a juvenile. This came as a big surprise as this is actually the least common species we see in Manx waters, in fact, over the last four years we have had an average of just seven sightings per year. Usually sightings are predominantly offshore, more than six miles out, so it is very interesting that all of our recent sightings have been extremely close inshore, seen from the land or kayaks. Recent sightings have all been in the South; from The Sound, Langness, Port Grenaugh, Perwick Bay and Port St Mary.
A couple of days after the Short beaked common dolphins were first reported, we started getting our first reports of an influx of Minke whales, again in the South of the island. It began with one or two sightings South of The Calf and then over the next few days perhaps as many as twenty or thirty individuals were seen feeding, all between Langness and the Calf. During this time period, hundreds of Gannets were seen diving in the same area, a good indicator that there was plenty of food around. As Minke whales are generally solitary animals, it was interesting to see so many feeding in such close proximity to one another, but this does occur when food is plentiful.
On the 30th June we had reports from various observers of a pod of at least twelve Risso’s dolphins travelling down the East coast.The first report was at 13:30 from Douglas then throughout the afternoon numerous observers reported them at various locations allowing us to track their movements down to The Sound, where they were last seen at 20:50. The following day, during a land-based survey, a large group of Risso’s dolphins were seen again, this time off Niarbyl just before midday. The similar group size means it is likely that this was the same pod as the day before. A week later, we had a report of a larger group of twenty Risso’s South of the Calf which were seen again three days later off Dalby. Here in Manx waters, we are very lucky to have an inshore population of Risso’s dolphins. In most parts of the world they prefer deep waters, perhaps two thousand metres deep, and as a result, the species is severely understudied worldwide.
We also carried out some outstanding land-based surveys throughout this period of high productivity. On the 30th June, we surveyed for three and a half hours at Port St Mary behind the Ledges. During this survey, we observed three Minke whales, a pod of around six Short-beaked Common dolphins, the twelve Risso’s dolphins mentioned before and several groups of Harbour porpoise. All of the species were displaying typical feeding and foraging behaviour; surfacing irregularly in the same area, often moving in different directions. The Minke whales were observed displaying behaviour which is not commonly seen in this species in Manx waters; they were incredibly active, swimming at speed, lunge feeding and even breaching. Another land-based survey was being carried out looking South of the Sound at the same time, during which at least ten Minke whales were seen, along with a number of groups of Harbour porpoise.
This is the first time we have ever had four species observed during one land-based survey since we began conducting research in 2007, and such an abundance of top predators suggests a healthy marine environment in Manx waters.