Sea Pen Distribution from Irish Nephrops UWTV Surveys

Sea pens (Order Pennatulacea) are habitat-forming benthic cnidarians and are recognised as Vulnerable Marine Ecosystem (VME) indicator taxa. They provide structural complexity in benthic habitats and are important indicators of benthic habitat condition and biodiversity.

The Marine Institute conducts annual Underwater TV (UWTV) surveys of commercially important Norway lobster (Nephrops norvegicus) grounds following ICES UWTV Survey protocols( https://doi.org/10.17895/ices.pub.8014). During video annotation, the presence or absence of sea pen species is recorded as ancillary environmental information alongside Nephrops burrow counts. Four sea pen species are routinely recorded during Irish Nephrops UWTV surveys: Funiculina quadrangularis, Pennatula phosphorea, Virgularia mirabilis, and Kophobelemnon stelliferum.

This dataset provides quality-assured presence–absence records of four sea pen species collected from the known spatial distribution of Nephrops grounds within Functional Units (FUs) 16, 17, 19, 20–21 and 22. The dataset currently includes observations from 2019 onwards and is updated annually as new survey data become available.

Functional Units: • FU16: Porcupine Bank Nephrops grounds. • FU17: Aran, Galway Bay and Slyne Head Nephrops grounds. • FU19: Western Irish Sea Nephrops grounds. • FU20–21: Labadie, Jones and Cockburn Banks Nephrops grounds. • FU22: The Smalls Nephrops grounds.

Sea pen observations are recorded for each UWTV station using video imagery. Presence–absence records represent observations made within an individual camera tow rather than the precise location of individual organisms within the tow. Consequently, the reported coordinates correspond to the UWTV tow location (typically the tow midpoint) and should not be interpreted as the exact position of individual sea pen colonies.