Shellfish Observer and Skipper Self-Sampling Programmes

Each year since 2009-present Marine Institute (MI) staff or contractors go to sea on inshore fishing vessels to observe and record fishing activity. About 50-80 day trips are completed annually although this varies year on year and was lower earlier in the time series. The data recorded in observer trips include the catches, landings and discards of several species such as Homarus gammarus (Lobster), Cancer pagurus(Brown Crab), Maja brachydactyla (Spider Crab), Necora puber (Velvet Crab), Buccinum undatum(Whelk), and the bycatch associated with these fishing events. Furthermore, all individuals or a sample (depending on catch volume) of the target species captured are measured to the nearest mm and their sex is determined providing a significant amount of valuable biological information for these species. The observer programme provides data at the level of individual fishing operations in contrast to fishery dependent data collection programmes which report aggregated data. The sampling levels of 50-80 trips is low relative to the thousands of trips undertaken by the Inshore fishing fleet annually. Furthermore there is high variance between vessels (related to location of fishing). The low sampling level and high variance reduces precision and even accuracy in these data sets especially when reported to local level where the data supports are diluted.