Posted by: orcaweb | June 14, 2017

“I have a question..”

Hiya, it’s Sophie here, back from another week out at sea aboard the Pont-Aven.

In our role as Wildlife officers it’s our job to engage with the public and pass on our enthusiasm and knowledge. It’s a really great feeling to answer people’s curious questions about these charismatic but often enigmatic animals.

However, we can’t help but notice that there are a few questions that we get asked a lot more often than others. So I thought I’d share with you some of the most common we get asked, with some answers, in case you’ve been wondering some of these too. And if you board Brittany Ferries in the future you can impress us with your knowledge!

What time will the Dolphins arrive?  When is the best time to see Whales and Dolphins?

Now, despite being a Wildife Officer, wildlife does not take orders. There is no real predicting what time a cetacean may pop up and say hello. What we can say is that our likelihood of seeing whales and dolphins will depend on the time of year, and where we are on our crossing. So you don’t necessarily have to get up a dawn to have a great sighting, but of course, the longer you watch, the more likely you’ll spot something. So getting up early means making the most of the daylight.

The summer months of July-September are the peak times for cetacean watching in the Bay of Biscay and are when we run our Sea Safaris on board the Pont-Aven. However we have still had some great crossings earlier in the season as well, as you can tell from previous blogs! We also tend to get more activity when we are crossing the continental shelf and into the southern part of the Bay. An hour or so out of Santander is also a great area over the Torralavega and Santander Canyons. But really, you never know when you’re going to get a great sighting, something that makes whale watching so addictive!

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Beautiful sunrises, but they don’t guarantee sightings

Why do the dolphins come to the ship? Are all the whales going to be far away?

We often see common and striped dolphins swimming towards the ship, under and around it. And for the most part, this is purely out of curiosity and for fun. It makes great viewing and passengers can’t help but be charmed when they get a closer look. But a lot of people wonder why, and ask if the boat churns up water and fish. While we do sometimes spot dolphins feeding from the Pont-Aven, it is not as a result of the boat’s propeller, rather we just happen to be near shoals of prey that they are feeding on.

Dolphins will approach all sorts of vessels and it is well documented how they ride the bow wave at the front of a boat. This surfing enables them to move at considerable speed with minimum energy expenditure.  However, the Pont-Aven is just a bit too large that they can’t quite stay in the bow wave, and we move too fast for them to keep up indefinitely, so eventually we leave the pods of dolphins behind.  After the ferry has outpaced them we often see them jumping in the waves of the Pont-Aven’s wake.

Whales on the other hand do not come in to the boat in the same way many dolphins do. That doesn’t mean we don’t sometimes see them close, as we can do if we’re lucky. Whale blows can be seen nearly at the horizon, but we’ve often had the sneaky beakies, – the Cuvier’s beaked whales, pop up incredibly close to the ferry.

In the case of whales, it’s often that they come up to breathe wherever and whenever they need it…if it’s close to the ship or not!

scarred cuviers

A scarred male Cuvier’s beaked whale, part of a trio that calmly swam by the Pont-Aven on Wednesday – easily visible without binoculars.

How fast can they swim?

It does depend on the species, and there are conflicting reports and estimations. The top speed of cetaceans is normally only a speed they can maintain in short bursts, compared to a slower ‘cruising’ speed. Their torpedo like body shape is adapted to reduce locomotive drag as they move through the water. We often see the dolphins ‘porpoising’ through the water as well. This is a series of regular long jumps as they swim. This behaviour might look like a lot of effort, but it actually can conserve 30% of the energy they would have used if they were just swimming in the water. This is because there is less resistance during the time spent travelling than when the move through water.

The Sei whale is thought to be the fastest of the great whales with a top speed of 50 km/h. bottlenose dolphins can have a top speed of around 40-50 km/h but swim at around 10 km/h when not hunting or fleeing danger. With the common dolphins it is thought they can swim in excess of 25 km/h in a short burst. Of the small cetaceans, the Dall’s porpoise (native to the North Pacific) can swim the fastest at about 55km/h, almost as fast as a orca!

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A Common dolphin porpoising through the water

What is the whale blow? But in Finding Nemo…

All cetaceans will blow and exhale as they surface, however with the great whales, this creates a blow that can be seen from a considerable distance. Fin whale blows can be up to eight meters high and a blue whale can create twelve meter high blows! Unfortunately this answer has some ramifications for the accuracy of Finding Nemo. As the trachea and esophagus of whales are not connected, they cannot swallow water and then exhale it out their blowhole. The whale would have just swallowed Dory and Marlin whole and they’d have ended up in the stomach. The whale blows that we can spot from the deck are created when the whale exhales through the blowhole on the top of its head. The air inside the lungs is warm and moist, and this moisture condenses in contact with the cool air, forming the misty clouds we see. There’s also some mucus mixed in. After all, they are the nostrils of a whale.

Fin whale blow

A fin whale with the remnants of it’s blow suspended in the air

How do Dolphins sleep? Do they sleep?

Cetaceans are what we call conscious breathers, this means breathing is something they have to think about, unlike humans. (But I bet you’re thinking about your breathing now). They have to consciously flex their muscles to open their blowhole, and when the muscle is relaxed, the blowhole is closed. This presents them with a problem if they want to rest, because if they need to actively breathe. Studies have shown that bottlenose dolphins engage in what we call unihemispheric sleep, where they are literally ‘half-asleep’. They can rest half their brain at a time, while letting the other half keep their body ticking over. Each side of the brain controls the opposite side of the body, so when the right hemisphere of the brain is resting the left eye will close, letting them sleep with one eye open. This enables them to rest without losing consciousness, as well as be vigilant for approaching dangers, and keep moving. They share this ability with certain bird species that must migrate over water.

What’s the difference between a porpoise and a dolphin?

Porpoises and dolphins are both in the order Odontoceti – the toothed cetaceans. However despite being closely related they are genetically distinct enough to be grouped into two different families – dolphinae (dolphins) and phocoenidae (porpoises).

This genetic distinction is evident in physical differences as well. Porpoises are generally smaller than dolphins with a more stout build compared to the dolphin’s longer body shape. Porpoises also have spade shaped teeth compared to conical teeth of dolphins. The dorsal fin of dolphins is a much more sickle shape than the equilateral triangle of the porpoises. And while they both have a rounded melon they porpoises lack the longer beak that most dolphins possess.

Can you recognise individual cetaceans here?

Yes, and no. It is much easier to determine individuals when you have a small well studied population that are resident to an area. Such as the bottlenose dolphins around Scotland, and the northern and southern resident groups of orca off the coast of Canada and the USA. This is usually based on variations in the dorsal fins, and building up photo catalogs of the individuals in an area. There are also catalogs of species when they have markings that differentiate them, such as using the mottled patterns of blue whales. However, in regards to the thousands of common dolphins that move through the bay, we cannot tell if it is the same pod we saw earlier in the week.

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It’s a big ocean out there. A single tiny dolphin jumps in the foreground against a cloudy sunrise.

Well, that’s all for now. Heather and Andy are back on board the Pont-Aven for another week of whale watching. The weather is forecast to be quite good so here’s to them having a great week with lots of cetaceans!

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