MARINElife Survey Report: Liverpool-Belfast 'Stena Mersey' 08th - 09th September 2018

Maggie Gamble and Harry Ashcroft, Research Surveyors for MARINElife
Weather: Visibility: Mainly good but with early rain then dull and overcast; Sea State: 2-5; Swell: 0-2; Wind: force 1-5 NW

Summary of Sighting

Marine Mammals
Grey Seal Halichoerus grypus 3

Fulmar Fulmarus glacialis 10
Manx Shearwater Puffinus puffinus 84
Gannet Morus bassanus 91
Cormorant Phalacrocorax carbo 10
Eider Somateria mollissima 6
Common Scoter Melanitta nigra 3
Great Skua Stercorarius skua 1
Black-headed Gull Chroicocephalus ridibundus 11
Great Black-backed Gull Larus marinus 2
Lesser Black-backed Gull Larus fuscus 10
Herring Gull Larus argentatus 11
Common Gull Larus canus 16
Kittiwake Rissa tridactyla 11
Little Gull Hydrocoloeus minutus 1
Common Tern Sterna hirundo 8
Guillemot Uria aalge 26

Other marine wildlife sightings

Basking Shark Cetorhinus maximus 1

Arriving in Birkenhead Port we were very soon boarded on the Stena Mersey and shown to our cabins. As the ship cleared port we were escorted up to the bridge where we were welcomed by the captain and bridge crew before beginning our surveying.

Leaving the Mersey Estuary and entered Liverpool Bay visibility was poor with intermittent rain and a sea state of up to 5, but moving further into the Irish Sea conditions thankfully improved. Our route was to the south of the Isle of Man and throughout the voyage we looked hopefully for cetaceans but unfortunately failed to spot any on this survey. However, we did log some marine mammals, with the unmistakable long heads of Grey Seal appearing on three occasions above the sea surface.

Basking shark RPJOn the far side of the Isle of Man travelling north up the Irish coast I was surprised to pick a fairly distant but unmistakable large triangular first dorsal fin of a Basking Shark swimming just sub- surface. The sea state had suddenly dropped to 1 in this area so probably there was some plankton near the surface allowing it to filter feed as it cruised slowly along. This shark is the second largest fish in existence but there are still a lot of unknowns about the species. The sea around the Isle of Man is a known hot spot for Basking Shark during the summer.

Indulging in a bit of post-sighting 'Basker' reading, I was shocked to find that up until the1970s they were the subject of an eradication program in Canadian Pacific waters as they were regarded as a nuisance. Thankfully what is left of that population is now protected - except from accidental by- catch!

For most of the survey we had a slow but steady sightings of seabirds to keep us attentive, mostly Gannet, Manx Shearwater and various gull species. I find all seabirds fascinating but certainly I never tire of watching the shearwaters working the wave fronts with that one wing tip just shy of the surface!

Little Gull Peter Howlett 12Due to the time of year, we did not undertake a survey on the return leg of the journey, leaving Belfast Lough in the late evening. Instead, we had a comfortable night's sleep and arrived back into Birkenhead Port early the following morning.

As ever, our thanks go to the very helpful and friendly staff and crew of Stena Mersey for allowing MARINElife to continue this survey.

Maggie Gamble and Harry Ashcroft, Research Surveyors for MARINElife (Registered Charity No. 1110884; Registered Company No. 5057367)

Basking Shark Photo: Rob Petley-Jones
Little Gull Photo: Peter Howlett