Monitoring of Yellow Trumpet Anemone Parazoanthus axinellae at Pen Cristen, Bardsey Island dataset https://portal.medin.org.uk/portal/start.php?tpc=007_NRW_DS110689 Yellow trumpet anemone Parazoanthus axinellae is primarily a south-western species, found at Bardsey Island and is close to the northern boundary of its known distribution at this location. This species has been selected as an attribute for monitoring the condition of reefs in the Special Area of Conservation (SACs). In 1999 an assessment of appropriate methods was made to look at monitoring the abundance and population structure of Parazoanthus axinellae and the erect branching sponge Axinella dissimilis. The trials focused on comparing different techniques to find the one that was most repeatable and therefore sensitive to population change. Trials took place at Pen Cristen, on Bardsey Island. Subsequent monitoring of the Parazoanthus axinellae assemblage has occurred annually at this location when weather conditions allow. The purpose of this data capture was to monitor the numerical abundance, percentage cover and distribution of individuals within the dominant Parazoanthus axinellae assemblage using a quantitative photographic approach. This will contribute to condition assessment of the reef feature in the Pen Llyn a'r Sarnau SAC. 20111231