To round up sea slug January before we move onto sponges, I wanted to have a look at the amazing difference in community and diversity of sea slugs across our hubs in the UK.

The communities you find can change a few miles down the coastlines, and there are species you can find in Cornwall and Devon that have never been seen in Scotland, and vice versa. To look at this further I’ve downloaded all sea slug iNaturalist recordings for these areas.

Here’s a brief summary of the main stats on diversity and abundance, but bare in mind some of our newer hubs haven’t had as much search effort yet, especially those that are harder to get to. There will likely also be higher species numbers in National Biodiversity Network data.

Hub Name Number of Species Number of Observations
Mount Batten 21 116
Castle Beach 22 289
Menai Bridge 57 757
Ovingdean Beach 3 4
East Sands 3 13
Kilve Beach 0 0
Beadnell Haven 3 12
Lee-on-the-Solent 0 0
Shoeburyness 2 5

The Menai Strait certainly seems to be the place to go for rockpool slug diversity! Huge well done to the volunteers down there that have been finding such an incredible variety of species! But remember, the hub areas used on iNaturalist won’t include observations from snorkelling or diving, and either way I’m sure there are plenty more species to be recorded rockpooling at our newer hubs particularly.

To visualize the different communities, I’ve made an interactive map showing the 1st, 2nd and 3rd most common species recorded currently for each hub. You may have to zoom in on a particular hub to see all of them! Click on each image to get a link to some species information about the slug, and to see the owner of the image. While some hubs have yet to record any on iNaturalist, I can’t wait to see how many you have recorded by the end of summer!

Thanks for having a read guys! See you next month to look into the Sponge diversity around the UK!

Take a look at the appendices below to see the breakdown of each hubs’ slugs!

Menai Straits, Wales:

Photo Common Name Latin Name Number of Observations
Crowned Aeolis Facelina auriculata 71
barnacle-eating dorid Onchidoris bilamellata 63
Pink Coryphella Edmundsella pedata 43
Hairy Spiny Dorid Acanthodoris pilosa 37
Four-lined Polycera Polycera quadrilineata 37
Angular Seaslug Okenia nodosa 36
Sap-sucking Slug Elysia viridis 35
Sea Lemon Archidoris pseudoargus 34
Boston Facelina Facelina bostoniensis 32
citrine nudibranch Pelagella castanea 30
NA Aeolidiella glauca 27
NA Tenellia cuanensis 25
NA Palio nothus 24
NA Aeolidiella alderi 21
Crimson Hermaea Hermaea bifida 19
Striped Fjordia Coryphella lineata 16
Slender Eolis Coryphella gracilis 16
NA Aeolidia filomenae 15
Winged Thecacera Thecacera pennigera 12
Side-gilled Seaslug Berthella plumula 11
Neat Aeolid Cuthonella concinna 10
NA Tenellia foliata 10
NA Dendronotus keatleyae 10
Branched Sapsucker Placida dendritica 9
NA Atalodoris pusilla 9
NA Tenellia aurantia 9
Minute Aeolis Eubranchus exiguus 8
crested aeolis Antiopella cristata 8
NA Coryphella browni 8
Humped Ancula Sea Slug Ancula gibbosa 7
Crowned Seaslug Doto coronata 7
Velvet Dorid Jorunna tomentosa 7
Three-coloured Aeolis Eubranchus tricolor 6
NA Doto koenneckeri 6
NA Polycera norvegica 6
Johnston’s balloon eolis Tergipes tergipes 5
Alder’s Seaslug Alderia modesta 4
Orange-clubbed Sea Slug Limacia clavigera 4
Flat Limapontia Limapontia depressa 4
NA Doto millbayana 4
NA Eubranchus farrani 3
NA Janolus hyalinus 2
Salt-and-pepper Nudibranch Caloria elegans 2
NA Rostanga rubra 2
NA Eubranchus vittatus 2
NA Tenellia caerulea 2
NA Capellinia fustifera 2
NA Atalodoris sparsa 2
NA Doris berghi 2
NA Eubranchus viriola 2
Fuzzy Onchidoris Onchidoris muricata 1
Rim-backed Nudibranch Palio dubia 1
club-gilled nudibranch Eubranchus pallidus 1
Embleton’s Aeolis Embletonia pulchra 1
NA Geitodoris planata 1
Tuberculate Dorid Adalaria proxima 1
NA Doto hydrallmaniae 1

Castle Beach, Falmouth:

Photo Common Name Latin Name Number of Observations
Spotted Seahare Aplysia punctata 119
Sap-sucking Slug Elysia viridis 43
Side-gilled Seaslug Berthella plumula 33
Crowned Aeolis Facelina auriculata 18
Orange-clubbed Sea Slug Limacia clavigera 16
NA Aeolidia filomenae 15
Velvet Dorid Jorunna tomentosa 11
NA Aeolidiella alderi 9
Gaudy Babakina Babakina anadoni 9
NA Spurilla neapolitana 6
NA Geitodoris planata 4
NA Rostanga rubra 4
White Aeolis Favorinus branchialis 3
Shag-rug Nudibranch Aeolidia papillosa 3
NA Discodoris rosi 2
Four-lined Polycera Polycera quadrilineata 2
Hairy Spiny Dorid Acanthodoris pilosa 1
Branched Sapsucker Placida dendritica 1
NA Trapania maculata 1
NA Facelina annulicornis 1
crested aeolis Antiopella cristata 1

Mount Batten, Plymouth:

Photo Common Name Latin Name Number of Observations
Side-gilled Seaslug Berthella plumula 41
Sea Lemon Archidoris pseudoargus 19
NA Aeolidiella alderi 11
Hairy Spiny Dorid Acanthodoris pilosa 9
Crowned Aeolis Facelina auriculata 7
Orange-clubbed Sea Slug Limacia clavigera 5
NA Aeolidia filomenae 4
Spotted Seahare Aplysia punctata 3
NA Janolus hyalinus 3
Angular Seaslug Okenia nodosa 3
Sap-sucking Slug Elysia viridis 2
NA Palio nothus 2
NA Spurilla neapolitana 1
Depilatory Seahare Aplysia depilans 1
White Aeolis Favorinus branchialis 1
NA Geitodoris planata 1
NA Rostanga rubra 1
Shag-rug Nudibranch Aeolidia papillosa 1
NA Polycera norvegica 1
citrine nudibranch Pelagella castanea 1
NA Doris berghi 1

Ovingdean, Brighton:

Photo Common Name Latin Name Number of Observations
Sap-sucking Slug Elysia viridis 2
NA Aeolidia filomenae 2
Side-gilled Seaslug Berthella plumula 1

Beadnell Haven, Northumberland:

Photo Common Name Latin Name Number of Observations
Side-gilled Seaslug Berthella plumula 6
Spotted Seahare Aplysia punctata 3
Sea Lemon Archidoris pseudoargus 3

East Sands, St Andrews:

Photo Common Name Latin Name Number of Observations
Spotted Seahare Aplysia punctata 8
Sea Lemon Archidoris pseudoargus 4
barnacle-eating dorid Onchidoris bilamellata 1