Posted by: orcaweb | May 24, 2013

Common Dolphins and a Basking Shark spotted by our guest Wildlife Officer!

Gannet Colony - Rouzec Sept Isles 030Common Dolphin - showing 'hourglass' pattern

Wildlife Officer Blog Cap Finistere 15th-22nd May 2013

Between 15th and 22nd May 2013 I had the joy of doing a temporary stint as a wildlife officer on the Cap Finistere. I haven’t been on it for a couple of years so it was nice to get acquainted with the ship again.
I boarded the ship in Portsmouth on the 15th and I was eager to get out on the water again despite the fact that on the previous day I had only just returned from a holiday in northern Spain with my wife in the glorious ‘Pico’s De Europa’ (Brittany Ferries offer good package deals to that region). I crossed the Biscay both ways on the ‘Pont Aven’ and I spent some pleasurable wildlife watching time on deck with both of ORCA’s wildlife officers Katrina and Imogen. Thank you ladies you were great company.

During the week we frequently saw common dolphins doing what they do best and that is approaching the bow of the ship to come and ‘play’ and then breaking off into the wake of the stern wave. The ‘Cap’ averages around 25 knots so keeping up with this ‘big white’ whale is beyond their ability. My final tally of ‘commons’ for the week was 450 animals and that’s a pretty conservative number. It was nice to see a couple of ‘calves’ in some of the pods we saw.

Sightings of the larger ‘great’ whales were poor and perhaps the weather has played a factor in that. I imagine that plankton growth in the Biscay might be affected by the water temperature and that of course has a knock on effect on the whole food chain right up to the apex predators like the whales. Perhaps this unseasonable weather is delaying this natural process just as it is on land. Plankton, in particular zooplankton, is such a vitally important factor in maintaining the bio-diversity of our marine eco-system and without it the entire system would collapse just like a knock on domino effect.
If you ever happen to cross the Biscay on the ‘Cap’ take a walk up to deck 10 where the children’s play area is located and on the wall there you will see an excellent chart which gives you an insight into the importance of plankton to marine life and how climate change is affecting the whole process.

We saw four whale ‘blows’ during the week and I couldn’t identify the animals by that alone. One such blow, a tall columnar ‘spout’, was a probable fin whale. We saw that in the area that you would expect to see them in the southern bay. We recorded very few striped dolphin, just 10 in fact. The two species can sometimes be difficult to differentiate and care has to be taken not to mis-identify them which something which I admit I have done in the past. They do occasionally associate with each other too which creates its own problems but there are subtle differences in their behaviour which can be spotted by the experienced eye. Sometimes when striped dolphins perform a high arching leap out of the water (usually in the ship’s wake) they undertake a kind of ‘roto-tailing’ aerial manoeuvre whereby it whips it tail in a circle and I saw one such animal doing this ‘belly up’. I’m confident that it was a ‘stripie’, as we cetologist types call them! Striped dolphins are a truly ‘pelagic’ species.

One species of ‘fish’ got me all excited and the passengers who were lucky enough to be with me on deck at time, it might have just been a fish but in fact it was the World’s second largest fish a basking shark. The animal was ‘filter feeding’ on zooplankton which consists of an ocean ‘soup’ of a myriad different species of small copepods, barnacles, decapods larvae, fish eggs, and deep-water oceanic shrimp. Basking Sharks are the only three filter feeding shark species, the others being the whale shark and the megamouth shark. The whale shark is the largest fish species in the World.

There were a considerable number of Manx shearwaters foraging in the turbulent waters in this area and amongst them there were some Balearic shearwaters. This is a ‘dumpier’ bird than its close relative and it is classed as a Critically Endangered species on the ‘IUCN Red List Category’. In mid-summer many ‘Balearics’ leave the Mediterranean and head north through the Bay of Biscay towards relatively cool British waters. This might be good news for British ‘birders’ who like to ‘twitch’ them but the reason they do this might be linked to climate change and the warming of the oceans making them less productive hence their need to move further north to find sufficient food.

At sea we saw the usual array of auks, fulmar, kittiwake, gull species, cormorant, Cory’s shearwater, Manx Shearwater, great skuas X 3 (or ‘bonxies’), Arctic terns, migrating barn swallows, 2 great northern divers including one bird on the water in the Channel Approaches in its striking summer plumage. We saw gannets galore and on one of the voyages we had a ‘feeding frenzy’ of plunge diving gannets close to the ship and amongst them there were many diminutive European storm petrels, I reckoned at least a dozen. This must happen quite often but feeding frenzies containing gannets are usually seen at a distance so you may not see the ‘stormies’ in the accompanying melee.

You never know what you might see when you cross the Bay of Biscay, to me that is the sheer pleasure and the challenge of voyaging across it. I will be crossing it many more times before the year is out!

Au revoir!
Elfyn Pugh,
Temporary wildlife officer.

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