Final week onboard the Western European Pelagic Shelf and Acoustic Survey (WESPAS)

31st Jul 2016

Common dolphin ©John Power

Sightings of common dolphins continued as the Celtic Explorer completed its track lines across the Celtic sea. By the 22nd and 23rd of July up to fourteen sightings of small groups had occurred while behaviours such as theatrical leaps, bow riding and feeding could be observed. When the call of “bottlenose” was roared out from the crow’s nest, the observers hurried to get photos of the pod which was traveling at a direct and steady pace towards the Irish Sea.  Much of the dolphin sightings have been concentrated around sand banks and underwater slopes where fish are often highly abundant.  Sightings however are often brief and a small dolphin can be difficult to see in a large ocean especially in rough and windy conditions.  Luckily for us a towed hydrophone regularly allows us to hear whistles and clicks made by toothed whales and dolphins. The image shows whistles made by some vocal common dolphins.

Above pictures ©John Collins

The Celtic sea provided multiple sightings of sunfish along with an impressive breaching Bluefin tuna, by far the most interesting fish species sighted, at least for the time being.. The 23rd provided the usual sightings of common dolphins but also a single striped dolphin which cruised past the bow while breaching all the while. This massively aided us in identifying it as a striped rather than common dolphin as the two species are similar in size and colouration. The wind speed and sea state thankfully dropped in the evening and we were ecstatic to see the blow of a large baleen whale. As we got closer to the animal it was apparent that it was a fin whale and that there were two animals! Amazingly up until this point we had only seen one lone fin whale while having spent nearly three weeks covering shelf waters. 

Fin Whale © John Power

The 25th didn’t live up to our ever high hopes as it provided only a few glimpsing views of common dolphins, however, even with moderate visibility the 26th proved to be a fabulous day as we had a total of sixteen sightings. The morning began with a single bottlenose dolphin passing us by a flurry of a dozen common dolphins ensued with a couple of large whale blows two of which were positively identified as fin whales. To finish off the day a pod of twenty bottlenose dolphins were observed travelling close by on our starboard side. 

Bottlenose dolphins © Niall Keogh

It looked like we were back in the large whale zone as the 27th produced multiple fin whales along with the reliable common dolphins. Two of these ocean giants past right by our bow clearly showing the chevron on the lower right jaw. The distinctive tall column like blow was clearly seen hanging in the air. At twenty plus metres long they are truly magnificently sized beasts.

Fin Whale © John Collins

By night we were destined to see beasts of another kind. As the CTD (an oceanographic recording instrument) was being retrieved the deck lights had attracted bait fish that were feeding on Zooplankton at the surface. The slender fish leaped out of the water thrashing side to side. Gar fish dashed across the surface snapping at the fish. A shadow seemed to be forming in the lit up water and as it dits reach. We swiftly began discarding the samples of fish caught that evening out of an interest to see what else was there just out of the reach of our lights. This surely drew upwards of fifteen blue sharks to the boat with the most seen at any one time being eight animals! Surely this couldn’t get any better? Off course the old reliable couldn’t miss out on this chaos. Five common dolphins darted into the shoaling fish clearly using the boundary between light and darkness to launch into the school. We could clearly see these dolphins coming from all sides of the fish and erupting up through the shimmering mass. It is a rare occasion to see dolphins hunting that clearly and only metres below us! What an amazing experience to observe the madness of a feeding frenzy, I believe we all fell into our beds that night with a sense of realisation that we most definitely chose the right path in life. What an unbelievable experience, one we are not going to forget in a hurry!

Blue sharks © John Power

Our final days concluded with yet more common and bottlenose dolphins to the north west of France. Twenty six species of sea bird were seen including the four skua species of the North Atlantic, Barolo shearwater was the rarest of five species of shearwater, Wilsons was the rarest of three Petrel species and other species included grey phalarope and yellow legged gull. After almost four weeks at sea and traveling hundreds of miles through Irish waters I think it is safe to say that Mick, Sean and I will be happy to set foot on dry land while revelling about the many truly unforgettable sights we shared. Thanks to the IWDG for giving us this opportunity and to the fisheries, Birding and crew members of the Celtic Explorer for sharing your knowledge and helping make the experience as memorable as it was. Feeling deeply enthused about the future we say goodbye and until next time!

- Blog by John Collins

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