Penzance-Isles of Scilly 18 September

Summary of sightings:

Marine Mammals

Common Dolphin Delphinus delphis 35

Risso’s Dolphin Grampus griseus 2

Unidentified small cetacean 4

Seabirds

Fulmar Fulmarus glacialis 1

Manx Shearwater Puffinus puffinus 28

Gannet Morus bassanus 114

Herring Gull Larus argentatus 10

Great Black-backed Gull Larus marinus 6

Guillemot Uria aalge 25

Larus sp. 1

Weather

Outward – sunny, almost cloudless sky, wind NE 3, excellent visibility

Return – intermittent sun and cloud, wind NW 3, excellent visibility

We boarded RMV Scillonian III on a very sunny, calm morning, the sea glassy. We were welcomed back by the Master and crew, who willingly shared their experienced observation skills with us. They were pleased that this week they hadn’t seen as many dead Gannets as in recent weeks, and we were relieved not to record any on this trip. The crew spotted some acrobatic Blue-finned Tuna soon after leaving Penzance, which they apparently see on most trips.

Common Dolphin (Library photo: Peter Howlett)

Sited on the port fly-bridge, sea-watching conditions were almost perfect, but despite this no Harbour Porpoise were seen by us. However, there were several sightings of Common Dolphin, including at least two juveniles. Distant splashes alerted us to their appearance followed by spectacular views as they performed long, sunlit leaps completely out of the water in their eagerness to reach the bow. Well offshore on the outward journey we noticed activity, which was fleetingly revealed as two large, darkish dolphins, fortunately also observed by a crew member who had a good view of the sickle-shaped fin, leading us all to conclude that they were Risso’s Dolphins, perhaps younger ones who had not yet become battle-scarred leading to the characteristic lighter appearance.

RIsso's Dolphin (Library photo: Peter Howlett)

Various ages of Gannets flew around, and we logged a few gulls, predominantly Herring. Several Guillemots were sitting on the surface or flying past on their rapid wing-beat flight. Having seen so many Manx Shearwaters on our August survey, including an almost constant flow along the Cornish coast, we saw relatively few on this trip, suggesting that many have now left the area for their wintering grounds in the seas off South America.

At St Mary’s harbour we noticed a couple of beautifully translucent jellyfish, with radiating fine lines, recognised as the aptly named crystal jellyfish Aequorea Victoria. Usually found off the west coast of North America, in the UK they are mainly seen off the south-west coast. Just off the northern beach the unmistakable hoarse calls of the previously Isles of Scilly-breeding Sandwich Tern drew our attention to around 50 birds, feeding, preening, and roosting, presumably on a stop-off on their migration to southern Europe and Africa.

Sandwich Tern (Library photo: Peter Howlett)

Our thanks go to the Isles of Scilly steam ship company staff and the Master and crew of the Scillonian III for their hospitality and invaluable assistance during this survey.

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