The prawn (Nephrops norvegicus) are common around the Irish coast occurring in geographically distinct sandy/muddy areas were the sediment is suitable for them to construct their burrows. Nephrops spend a great deal of time in their burrows and their emergence from these is related to time of year, light intensity and tidal strength. The Irish Nephrops fishery is extremely valuable with landings in recent years worth around €30 m at first sale supporting an important indigenous processing industry.
Purpose of Survey
The Marine Institute has been using underwater television surveys to independently estimate abundance, distribution and stock sizes of Nephrops on the Aran Grounds and Western Irish Sea. Data are also collected on Nephrops behaviour and the impact of fishing activity on the seabed.
How Under Water TV Surveys Work
During these surveys an under water video camera is towed over the sea bed for around 200m and 0.8 knots on a purpose built sledge. The number of Nephrops in the seabed are counted by experienced scientists. These burrow density estimates are then interpolated for the entire area of the Nephrops grounds using geostatistical methods.
Recent Survey Results
Each year the Marine Institute carries out three underwater TV surveys on the Aran Grounds, Galway Bay and Slyne Head grounds in the west of Ireland, in the Celtic Sea, and in the Western Irish Sea. Results of these surveys are submitted to annual ICES working groups. These recent reports can be downloaded for each of the surveys:
Areas Covered During the Marine Institute Nephrops UWTV Surveys 