Nephrops Underwater TV Survey FU22 The "Smalls" North East Atlantic Ocean 2006 - Present

• Main Author: Doyle, Jennifer
• Format: Dataset
• Language: English
• Published: Marine Institute, Ireland 2021
• Subjects: location; oceans; Burrows; Fishing Ground; North East Atlantic
• Online Access: https://dx.doi.org/10.20393/ae0f5162-feed-46e1-8a85-397ea6ecc9e5; http://data.marine.ie/geonetwork/srv/eng/catalog.search#/metadata/ie.marine.data:dataset.4598

Nephrops norvegicus are common around the Irish coast, occurring in geographically distinct sandy or muddy areas where the sediment is suitable for construction of their burrow dwellings. The Marine Institute carries out Underwater TV surveys annually of commercially important Nephrops stocks. This dataset provides quality assured estimates of Nephrops burrow densities over the known spatial and bathymetric distribution of the FU (functional unit) 22: the “Smalls” Nephrops ground. From 2006 to 2011 (UWTV) stations set at 3.0 nautical mile spacing over the known distribution. From 2012 onwards a randomised isometric grid of underwater television (UWTV) stations set at 4.5 nautical mile spacing. Underwater TV Survey reports for this Nephrops stock are available at: http://hdl.handle.net/10793/1428 Also available is the ICES Cooperative Research Reports which details use of UWTV surveys to assess Nephrops stock:https://tinyurl.com/ices-nephrops GIS shapefiles of FU22 and the “Smalls” Nephrops grounds are provided. This dataset covers the period of 2006 and is ongoing. One hundred percent of the survey grid was covered in all years except in 2015, where 83 percent of the grid was covered. These 7 stations in 2015 could not be completed due to very poor or nil visibility conditions encountered at seabed. For these stations density estimates were filled-in using and average of historic values within 2nmi (buffer2estimated). Dataset fields are Nephrops Functional Unit Number; Survey Code; Year; UWTV station number; Date-Start of UWTV track; Time_Start of UWTV track; Date-End of UWTV track; Time_End of UWTV track; Decimalised longitude and latitude midpoint of the UWTV station track; Adjusted density (Nephrops burrows/m²) ;Length in metres of the UWTV station track; Field of View of camera system in metres; Total Nephrops burrow count; Nephrops Fishing Ground Name; Source of positional data to calculate UWTV station track (USBL sled GPS, SHIP GPS, Layback, estimated GPS, buffer2estimated); Camera system used (SD = standard analogue system, HD = high definition system); Data Extraction method (SQL, MSAccess); Data Status (Final for analysis); Research Vessel Name; Correction Factor (Density / Correction Factor = Adjusted Density) and Depth (metres). Entries with NA means data is not available.