Unexpected visitors

As an extreme heatwave continues to blaze through the North Icelandic summer, the last two weeks have been a blur of whale research for the team. We have collected our first blow samples, aerial images, acoustic recordings and plenty of behavioural data. We’ve been elated, exhausted and grateful for the calm weather. We’ll provide a more detailed update in the next blog – first, I wanted to highlight some whaley unusual visitors to Skjálfandi Bay and interesting observed behaviours.

A pod of orcas – a big surprise for a Skjálfandi summer!

Odontocetes from the deep

On a typical summer’s day, the bay is occupied by baleen whales (humpbacks and minkes), dolphins and porpoise. For baleen whales, their prey is mostly found in the upper layers of the water column, as a result of phytoplankton blooms under the midnight sun. This July, however, we’ve been joined by two larger toothed whales (odontocetes) that normally inhabit deeper offshore waters – pilot whales and northern bottlenose whales.

Both species arrived in early July and have been seen sporadically in the area, including adjacent Eyjafjörður. We found it curious that both species, seldom seen in the coastal waters of the north, arrived at the same time. Both feed on fish and squid at depth, so perhaps an inshore movement of their preferred prey led them here? Acoustic recordings of echolocation clicks would provide some clues – unless we were lucky and they passed near to our long-term hydrophone in the west, we weren’t able to collect any so far.

Two northern bottlenose whales
The bulbous head is characteristic of northern bottlenose whales

Alternatively, some disturbance (e.g. human noise) may have driven both species into the area. We were a bit nervous about this possibility as both species are prone to strandings. Pilot whales are famous for their mass stranding, with more than 50 animals fatally ashore in nearby Langanes in 2019. Meanwhile, six bottlenose whales died in Skjálfandi Bay in 2018, following their persistent, unusual occurrence. However, both species appear to be behaving ‘normally’. The bottlenose whales have mostly been seen in the middle of the bay, diving for 11-20+ minutes each time, with a group size of 2-8. Pilot whale pods were far larger (30-50, as expected) and also found in deeper waters. Both move very quickly and are hard to follow!

Other than their typical diving and movements, we were fortunate to witness an incredible behaviour. Flo and Synnøve joined North Sailing for their evening whale-watching trip. Early in the trip, they saw a pod of pilot whales behaving ‘normally’. A while later, they came across some humpbacks. While watching the third humpback (known by the team as ‘Long’ for its long dorsal fin), they saw some small blows in the distance – the pilot whales. They then travelled straight towards Long and swum around it. Long responded by rolling and splashing at the surface – it seemed to be distressed by the pilot whales’ presence! While this is rarely seen, it isn’t too surprising. Pilot whales are known to harass several larger species (including orcas, sperm whales, baleen whales). However, the purpose of this is unknown – competition for food, feeling threatened, just for fun? Acoustic recordings from the encounter may have provided further clues. Regardless, it was incredible to witness.

Pilot whales around a humpback – harrassment?

Orca-strating magic

The big news of July came from the pilot and bottlenose whales. However, yesterday, we received the fabled message from whale-watching guides, the one we always dream of – ‘ORCAS IN THE BAY!’. Alyssa, Flo and Tom rushed out on the inflatable in the hope of collecting ID photos and acoustic recordings (we were planning to head out soon after for blow sampling anyway!). By the time we reached them in lumpy seas, they were in the far northwest of the bay. Consisting of three small groups (5 + 3 + 1 animals), they were fast swimming, dived for 5-6 minutes and changed direction every dive – not easy to follow. Consistently moving northwards, they seemed to be actively feeding on fish but we have no idea which species.

Three adult male (bull) orcas

At first, we thought we wouldn’t be able to follow them without travelling at very fast speeds – which would risk stressing the animals and we were not prepared to do. However, by travelling slowly northwards between dives, we could get close enough to the group of 5 to collect a few ID photos. With so little known about orcas in north Iceland, even a single photo can provide key information. We’ve shared our images with the Icelandic Orca Project in the hope of matching them to known individuals. We also dropped a hydrophone into the water twice near the pod but they seemed to be quiet. It was a wild ride and an absolute privilege to see them.

The research continues

It’s fair to say that these unusual sightings have disrupted our humpback whale research. On one trip, we ditched a blow sample to follow the northern bottlenose whales. On another, after following the orcas, we were low on fuel and had to return to the harbour. However, over the last two weeks we have still managed to collect both blow samples and aerial images! Most of these have come from Skjálfandi, where we have concentrated our efforts. However, we have also had two ‘away’ trips in the van, attempting to sample from land. The first was to Langanes – despite some excellent weather and plenty of fish (evidenced by giant flocks of seabirds), no humpbacks came close enough to shore for sampling. However, we haven’t given up hope – Langanes is a key control site with low vessel traffic, so we’ll head back there soon. The second was to the west Steingrímsfjörður and Eyjafjörður … more on that in the next blog, when we’ll go into more detail on research progress and introduce new team members!

Thanks as always to the University of Iceland’s Research Centre Húsavík for allowing us to carry out this work.

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