Wednesday, 12 August 2015

Plenty to see in the Irish Sea

Every summer Rockabill Island plays host to a lot of birds - 8,000+ breeding adults, roughly the same amount of chicks that hatch, and 52 species coming and going this year - and all on a small rocky island a bit smaller than a football pitch! But obviously Rockabill and its breeding birds are just one part of the large and complex ecosystem that is the Irish Sea. Being the keen zoologists we are, we're always delighted to spot some of the other 'charismatic' fauna that is to be seen around us.......

(...and we've sent records of the below species to the National Biodiversity Data Centre and Irish Whale and Dolphin Group....)


Earlier on in the season we had some excellent views of Minke Whales (which I had never seen before!) and a sizeable pod of Common Dolphins to our North. Andrew also spotted a Basking Shark a few kilometres to the East (not a cetacean I know..). Though these species were largely absent (or at least inconspicuous) from mid-June onwards, we have been treated to excellent views of several Harbour Porpoises close to the island throughout the season, including a calf swimming very close behind its mother. Needless to say we aren't used to seeing Porpoises in either Roscommon or Carlow, so each opportunity to watch these magnificent mammals was a real treat!

Harbour Porpoise.
Harbour Porpoise.
Harbour Porpoise.


Lions Manes proved to be the most common Jellyfish around Rockabill this summer, ironically followed by 'Common' Jellyfish in second, with a good number of the spectacular Compass Jellyfish making appearances from late June onwards. We had a few small Blue Jellyfish and the odd Barrell Jellyfish too, and a sixth species that we hadn't come across before (pun intended) - a Cross Jellyfish! (or what we think is a Cross Jellyfish, its surprisingly hard to get info on Jellyfish...)

Cross Jellyfish.
Compass (left) and Common/Moon Jellyfish (right).
Lions Mane Jellyfish.

Lions Mane Jellyfish (underneath).


Cetaceans can be hard to spot, and jellyfish come and go depending on the water, but we can always be guaranteed to be joined by a few Grey and Common Seals down at the piers. Though they were wary of our presence early on in the summer, they gradually grew more tolerant as the summer went on and allowed us some very confiding views. Watching their blubbery bodies hauled out on the rocks at low tide almost makes you forget how graceful and speedy they are once they get into the water. Once again - not many seals in either Roscommon or Carlow - so we took advantage of the few nice evenings we had to watch our mammalian neighbours with curioisity they couldnt help but reciprocate.

Grey Seal.

Grey Seal.

Grey Seal.

Common Seal.

Grey Seal.

Rock Pool Regulars!

We touched on the fantastic diversity in even the smallest rock pools in an earlier blog post (Here!), so we won't repeat ourselves except to encourage everyone to give them a closer look the next time you're beside the sea - you'll be surprised at what you might find!

Common Blenny ('Shanny') lurking amonst shelter in a rockpool.

Edible Sea Urchin.

Beadlet Anemone.

Brown Crab.
Common Shore (Green) Crab.
Dog Whelk.
Common Starfish.


  1. Fantastic pictures Brian. By the way, Basking Shark is not a cetacean !

    1. Thanks very much Richard. Haha, I noted that later in the sentence alright, I knew I'd have people highlighting it!