MARINElife Survey Report: Liverpool-Belfast 'Stena Mersey' 21st - 22nd April 2018

Emma Howe-Andrews and Karen Francis, Research Surveyors for MARINElife
Weather: Visibility excellent at 16-20km; Dry; Clear Skies and Sunshine; Sea State: 1-3; Swell: 0; Wind Force: 1-5; Wind Direction: NNE-E-S

Summary of Sightings

Marine Mammals
Bottlenose Dolphin Tursiops truncates 6
Harbour Porpoise Phocoena phocoena 3
Seal sp. 6

Fulmar Fulmarus glacialis 1
Gannet Morus bassanus 31
Manx Shearwater Puffinus puffinus 17
Shag Phalacrocorax aristotelis 6
Little Gull Hydrocoloeus minutus 1
Great Black-backed Gull Larus marinus 8
Lesser Black-backed Gull Larus fuscus 4
Herring Gull Larus argentatus 44
Common Scoter Melanitta nigra 2
Kittiwake Rissa tridactyla 16
Puffin Fratercula arctica 1
Guillemot Uria aalge 60
Razorbill Alca torda 9
Shearwater sp. 10
Gull sp. 123
Tern sp. 7
Auk sp. 7

Terrestrial birds
Grey Heron Ardea cinerea 1
Oystercatcher Haematopus ostralegus 1

With blue skies and the sun shining, we arrived at the Birkenhead Stena Line passenger terminal ready for our survey across the Irish Sea. The forecast was predicting smooth to slight seas, dry sunny conditions and good visibility, what more could we ask for? We could hardly wait to get started!

GBB Gull Peter Howlett 11After a quick and efficient check-in, we were on the bus and heading towards the ship. As we got closer we could see that the River Mersey was still and calm with a few rafting gulls on the surface whilst others soared over the MV Stena Mersey as we made our final approach. We were greeted onboard by Taylor at guest services who is always so friendly and helpful, and she organised for us to be escorted to the bridge for departure.

We were warmly greeted by the Captain and made to feel very welcome as we settled into our station on the starboard side. The bridge crew are always so friendly and accommodating and it is an absolute pleasure to have the opportunity to spend time with them and observe their work.

With an early departure, the MV Stena Mersey was under way and heading out into Liverpool Bay taking the north route towards the Mull of Galloway. It was low tide and the sandbars were exposed, bringing us our first mammal sighting, of five seals hauled out and lazing in the spring sunshine whilst another individual splashed in the surf. They looked to be a mixture of Grey Seal and Harbour Seal but due to the distance a positive identification could not be made. It was still great to see them.

The weather was amazing with excellent visibility, clear skies, sunshine and a sea state 2. We had south-easterly winds blowing at 11.3 knots and no swell making the conditions perfect for spotting cetaceans and it wasn't long before we did! Three Bottlenose Dolphin, two adults and one juvenile, feeding in a large smooth patch of water created from an upwelling, their beautiful grey colouration clearly visible.

The animals lingered for a little while before diving and disappearing beneath the waves. A small splash brought the second sighting, a possible Harbour Porpoise, 65 degrees off the starboard bow at 380 metres accompanied by a solitary circling gull.

After the excitement of these two great sightings it became a little quiet, but we were entertained with sightings of Great Black-backed Gull, Herring Gull and Lesser Black-backed Gull sweeping across the waves. Whilst surveying the surrounding area, we noticed a few splashes from diving and circling birds over a patch of water on the starboard side, which on closer inspection proved to be two Bottlenose Dolphin feeding! They charged through the water with the birds following overhead and then gradually disappeared into the wake as the ship continued its journey.

It really was a beautiful day at sea and as the excellent visibility and calm conditions continued we could see the east side of the Isle of Man in the distance. Our excitement grew after recent reports of large groups of Bottlenose Dolphin and Risso Dolphin being sighted around its shores, so we were hopeful of further sightings.

Our fourth sighting, a Harbour Porpoise, came shortly after we had sighted the Isle of Man with the animal hastily swimming away from the ship. We also started to record Manx Shearwater, Kittiwake, Fulmar, and Gannet during this time.

BND Adrian Shephard 08bWith the Isle of Man on the Stena Mersey's portside, we made our last two sightings of the survey, with a fifth large solitary Bottlenose Dolphin making lots of splashes 180 metres ahead of the ship moving towards the portside. The animal was accompanied by Manx Shearwater, Gannet and Herring Gull overhead and appeared to be feeding as it lunged and leapt clear of the water away from the ship and after its prey. The sighting generated some conversation between us, and we both agreed that it was one of the largest Bottlenose Dolphin we had ever seen and created quite a splash. The final sighting was a Harbour Porpoise feeding separately from the Bottlenose Dolphin.

With the odd Barrel Jellyfish and rafting Guillemot parent and fledgling pairs keeping us company, the ship approached the entrance to Belfast Lough. As the ship progressed, the afternoon sun created glare, initially on the portside but then moving ahead of the ship to starboard making surveying extremely challenging. This effected our recording area, and we recorded only a few more birds, and eventually we had to leave the bridge early as we unable to see past the bow due to the conditions. Despite the early finish, it was a fantastic survey, and we felt very lucky to have witnessed some of the great wildlife that inhabit the waters of the Irish Sea.

Huge thanks go to Captains Giovanni Maresca, his crew and the staff of Stena Mersey who made this a very enjoyable and memorable crossing with their kind hospitality, and to Stena Line for their continuing support.

Emma Howe-Andrews and Karen Francis, Research Surveyors for MARINElife (Registered Charity No. 1110884; Registered Company No. 5057367)

Great Black-backed Gull Photo: Peter Howlett
Bottlenose Dolphin Photo: Adrian Shephard