MARINElife survey report: Dover-Calais 13 December
13 December 2025
This was to be our last survey of 2025, Storm Bram had passed through the country midweek, but Saturday morning was calm and dry, a good omen for our crossing.
Pat joined me in Dover, and having obtained our passes, we went and joined the queue to board the Cote des Flandres.
On entering the bridge, we were welcomed by the bridge officers and Captain Larrieu and set up our equipment for the survey.

We left Dover on calm seas, with the low winter sun shining directly ahead through the bridge windows, bird identification was difficult as many were in silhouette. The seas were very calm and many of the birds were sat in sporadic loose rafts across the Dover Strait. Gannet, Herring Gull, Great Black-backed Gull and Kittiwake were in evidence as well as occasional auks. As we approached France, a Harbour Seal was spotted among a raft of Herring Gull, to be followed almost immediately by a group of three more seal seen together ahead of the ship. Shortly after that, we recorded some Red-throated Diver flying quickly past close to the surface.
Our outbound survey concluded at the outer breakwater in Calais. As in November, the inner harbour had several hundred birds, predominantly Herring Gull that were resting on the beaches and the breakwater. In addition, we were able to watch eleven Harbour Seal that were hauled out on the beach to the south of the mooring. Many sandbanks are exposed to the north of the harbour at low tide, and several thousand gulls were resting there.
Ninety minutes later, the turnaround completed, we headed towards England. No other marine mammals were recorded on the return transect. More divers were seen, but most birds belonged to large gull species. Most birds were resting on the water, but there were a couple of times when a Herring Gull found some food in the water and was mobbed by a couple 0f Black-backed Gull trying to steal an easy meal.

With Dover harbour entrance in sight, we thanked Captain Larrieu and the bridge crew for their hospitality, wished them a Joyeux Noel and headed below to rejoin the car and make our way home.
Carol Farmer-Wright and Pat Hatch, Research Surveyors for MARINElife (Registered Charity No. 1110884; Registered Company No. 5057367)
Weather
Outbound: wind SW-SE force 2-3, good visibility, with strong glare
Return: wind NW-WSW force 4, good visibility
Summary of sightings
Seabirds
Black-headed Gull Chroicocephalus ridibundus 5
Cormorant Phalacrocorax carbo 10
Gannet Morus bassanus 150
Great Black-backed Gull Larus marinus 53
Guillemot Uria aalge 12
Herring Gull Larus argentatus 161
Kittiwake Rissa tridactyla 31
Lesser Black-backed Gull Larus fuscus 4
Mediterranean Gull Ichthyaetus melanocephalus 1
Red-throated Diver Gavia stellata 7
Auk sp. 18
Gull sp. 3
Larus sp. 508
Marine Mammals
Harbour Seal Phoca vitulina 4

