It was a week full of harbour porpoises in the North Sea for ORCA OceanWatch!
This has truly been the week of the harbour porpoises on board KING Seaways. We had 9 grey seals and 3 unidentified dolphins in the distance but the stars, the harbour porpoises, numbered at over 35! On Friday in just 24 hours we had exactly 24 harbour porpoises! What a delight it was and how amazing to add to the sightings for ORCA OceanWatch!
It’s worth noting that conditions here in the North Sea have been fantastic, with mirror sea states and sunshine almost every day this week. This definitely helped in spotting the high numbers of our little harbour porpoises, as their tiny fins are hard to spot in any waves. On one particular day the conditions were so flat and clear that we could see mothers with their tiny little calves right beside the ship and even their tiny little blows! This had myself and all the passengers yelping with delight. On Thursday we were delighted to go and teach at Dover Marine Lab for Newcastle University Summer Schools. We spent the day with children teaching them about the wonderful whales and dolphins of the North Sea. Oh my, did they know a lot already! We were very impressed with their enthusiasm and knowledge and I hope these budding marine scientist go on to do great things in the future.
The harbour porpoise, in my opinion, is really the mascot of the North Sea. It is the smallest cetacean here in European waters but also our most sighted cetacean in the North Sea. They are only 1.7m at their biggest and are a very shy shallow water species, staying close to coastal waters. They are generally alone or in small groups. They are robust, small, and have no beak. Their most obvious feature is a centrally-placed dorsal fin, which is perfectly triangular in shape.
As with all cetaceans the harbour porpoise faces many threats. The main ones being by-catch, noise and chemical pollution. ORCA has surveyed here in the North Sea for over ten years now. Our data has found that the North Sea is a very important habitat for the harbour porpoise. By-catch estimates of harbour porpoise are as high as 4,600 per year, sadly, just here in the North Sea. This is a very vulnerable species and urgent action needs to be taken to reduce the impact of fishing on them. Recent studies have shown that harbour porpoises spend 90% of their time foraging. This research showed that in the North Sea the high vessel traffic caused a constant disruption to their feeding behaviour. The noise pollution from the vessels interrupts with their echolocation, the tool they use for hunting and finding food. In the long term this constant disruption in their foraging is resulting in reduced fitness on the harbour porpoises, i.e. less healthy animals. This can have a long term effect on their survival abilities and reproduction.
Currently there are harbour porpoise marine protected sites under consultation, however from our research and that of other scientists it is clear that this need to implement as soon as possible. They are being decimated by overfishing, pollution and vessel traffic and something needs to be done before these lovely animals start to decline further.
That’s all for this week folks, yay for the harbour porpoise!
ORCA Wildlife Officer- North Sea