IMIS

Both a towed sledge camera and a drop frame camera were used in these surveys. The video sledge was attached by a 400m cable with a USBL system, scaling lasers and an ancillary GoPro. A 0.1m2 day grab was also used as further ground-truthing but this information is not included in this dataset. Particle size analysis and Carbon & Nitrogen analysis were also carried out (not included in this dataset). Information on the substrate was collected and is included in this dataset. In total there were 13 successful sledge camera tows and 7 successful drop frame camera tows.

"This dataset contains information on the SACFOR abundance of benthic infauna species from video footage from selected Special Areas of Conservation in Northern Irish waters. The aim of this survey was to ground-truth previously acquired multibeam data for habitat types including macrofaunal assemblages, and gather data to support condition assessments at the selected SAC’s. The information in this dataset is taken from underwater camera footage (sledge camera and drop frame) but during this survey day grabs were also taken along with Particle Size Analysis (PSA) and Carbon & Nitrogen analysis but this information is not included in this dataset. The SAC’s selected are as follows; Red Bay SAC, The Maidens SAC, Skerries & Causeway SAC.

The camera sledge was attached by a 400m cable and had a USBL system and ancillary GoPro deployed on the sledge and in the moonpool of the ship and was fitted with lights and scaling lasers. The Drop frame was fitted with a High Definition (HD) camera and was used when substrates were not suitable for the towed sledge.

The survey took place on board the RV Corystes between 2017-09-25 and 2017-09-27. The survey of Red Bay was carried out on 2017-09-25 using the video sledge and there were 5 successful tows from this site. The survey of the Maidens was carried out on 2017-09-26 using the sledge camera and drop frame. There were 2 successful sledge tows and 4 with the drop frame camera. The survey of the Skerries & Causeway SAC took place on 2017-09-27 using the sledge camera. There were 3 sledge tows carried out initially but the ancillary GoPro flooded on the 2nd tow and the sledge became entangled with a fishing creel on the 3rd tow (this was successfully untangled by the crew). A 4th tow was then carried out to the eastern side of the Skerries & Causeway SAC. It is important to note that on 2017-09-27 there were rough sea conditions which may have an effect on the quality of the video. This was mitigated to the best of our ability by using two experienced marine biologists to review and analyse the video data."