CV17021 Nephrops Underwater TV (UWTV) Celtic Sea Survey - Leg 2

Annual second leg underwater television (UWTV) survey of abundance and distribution of Nephrops in the Celtic Sea Nephrops Grounds. The prawn (Nephrops norvegicus) are common in the Celtic Sea occurring in geographically distinct sandy/muddy areas where the sediment is suitable for them to construct their burrows. The Celtic Sea area supports a large multi-national targeted Nephrops fishery mainly using otter trawls. This survey was carried out by the Marine Institute on board the R.V. Celtic Voyager in August 2017 in the Celtic Sea. A total of 40 UWTV stations were surveyed successfully (good quality video footage), carried out over an isometric grid at 4.5nmi or 8.3km intervals. Mean density was calculated by dividing the total number of burrow systems by the survey area observed. Ten beam trawl tows were conducted providing important data on the benthic communities and size structure of the Nephrops population. All Nephrops caught were sorted by sex and maturity category, weighed and measured using the NEMESYS electronic measuring system. The fish catch was identified to species level and sampled by weight (kgs) only. The benthic catch was identified and weighed (g) and counted. No Conductivity, Temperature and Depth (CTD) data was collected during this survey due to technical problems. 1. To complete randomised fixed isometric survey grid of 40 UWTV with 4.5 nautical mile (nmi) spacing stations on the “Smalls” Nephrops ground (FU22). 2. To obtain 2017 quality assured estimates of Nephrops burrow distribution and abundance on the "Smalls” Nephrops ground 3. To collect ancillary information from the UWTV footage collected at each station such as the occurrence of sea-pens, other macro benthos and fish species and trawl marks on the sea bed. 4. To sample Nephrops and macro benthos using a 4 m beam trawl deployed at ~10 stations.