MARINElife blog: DFDS Dunkerque Seaways Dover-Dunkirk 30 March 2019

Helen Swift and Tom Forster, Research Surveyors for MARINElife (Registered Charity No. 1110884; Registered Company No. 5057367)

Weather: Outbound & return: Sunny but hazy, moderate visibility, wind northwest force 1-3, sea state 1, slight glare at times.

Summary of sightings:

Marine Mammals
Harbour Porpoise Phocoena phocoena 60
Unidentified Seal sp. 2

Seabirds
Arctic Skua Stercorarius parasiticus 9
Common Gull Larus canus 1
Common Scoter Melanitta nigra 49
Cormorant Phalacrocorax carbo 7
Fulmar Fulmarus glacialis 6
Gannet Morus bassanus 87
Great Black-backed Gull Larus marinus 7
Great Skua Stercorarius skua 1
Guillemot Uria aalge 60
Herring Gull Larus argentatus 11
Kittiwake Rissa tridactyla 72
Lesser Black-backed Gull Larus fuscus 4
Little Gull Hydrocoloeus minutus 3
Red-throated Diver Gavia stellata 5
Sandwich Tern Sterna sandvicensis 42
Auk sp. 12
Diver sp.8
Gull sp. 272
Larus Gull sp. 26
Skua sp. 1

For a while we had been wondering whether Brexit might disrupt the Port of Dover and prevent us from doing this survey. We were both so glad we could go ahead as it turned out to be an exceptional survey. Driving down in the warm spring sunshine we were hopeful the conditions would be good but on setting out it became clear they were near-perfect. Hazy sunlight from a cloudless sky silvered a sea broken only by low ripples. The silver sea merged imperceptibly to the hazy sky, but the diminished visibility had the advantage of cutting the glare, though the diffuse light made seabird ID challenging at times as even pale birds could look very dark against the silver glow. Tidelines shimmered and snaked over the water and we watched these carefully. Forming where the tide has swept together the microplankton these often attract fish which in turn attract cetaceans. Sure enough, soon after setting out black dorsal fins broke the stillness amidst the nearest tideline, and we saw our first Harbour Porpoise group. We did not have long to wait for more and within the first hour of the survey we had seen 18 porpoises. This alone had already beaten the most we have ever seen in a full survey here.

Harbour Porpoise Rick Morris 01a
Harbour Porpoise (Library photo: Rick Morris)

Amidst the constant porpoise sightings, we also noted a couple of seals and small numbers though a good variety of birds, the highlight of which was two flocks of Common Scoter streaming east.

A lull in the porpoise sightings as we approached the shallows off Dunkirk was fortuitous as it gave us time to appreciate the increasing diversity of birds with large numbers of Sandwich Tern (groups especially tending to sit atop each of the navigation buoys) and associating with them Arctic Skua - I suspect the latter was no coincidence noting Arctic Skua's habit of kleptoparasitism on terns. Divers started to appear too, all of which were probably Red-throated though we could only be certain with some as the fickle light and their tendency to fly at long distance made precise identification a challenge. A final flurry of porpoise as we approached Dunkirk itself left us on a total of 21 Harbour Porpoise for the outbound leg and as we paused whilst the ship unloaded, we wondered just how many we might see overall.

Sandwich Tern Rob Petley-Jones 01
Sandwich Tern (Library photo: Rob Petley-Jones)

The return leg was no disappointment. If anything, it turned out the outbound leg was only a starter to this the main course. Occasionally on surveys we have felt nearly overwhelmed by bird sightings coming almost too quickly to record; this was the first time we have ever felt like this with cetacean sightings. Porpoise seemed to be in large weakly associated groups spread out as singles and small parties over large areas and no sooner than we started to record one sighting, others would pop up at a different distance and bearing. The highlight was 8 separate sightings in 4 minutes which overwhelmed us; as I tried to log them as fast as I could Helen kept calling out new sightings with the crew joining in and spotting others we had not seen on the other side of the ship. I must admit it's probable some birds went by unrecorded during this period!

Amazing though this was, it was actually quite stressful trying not to miss anything and quite nice when the sighting rate slightly eased to the still incredible rate of a sighting every 3 minutes or so. The porpoise kept popping up all the way in to Dover and when we finally totalled up, we were amazed to realise we had seen a total of 60 Harbour Porpoise, not counting those spotted by the crew. This was an amazing experience and such a privilege to be out on such a beautiful day with so much wildlife.

Our thanks to the Captain and crew of Dunkerque Seaways for making us welcome and looking after us throughout the survey.