Changes in the dynamics of the Norwegian mackerel purse seine fishery – does it influence the representativeness of the reference fleet data?

Abstract

The last three years, the peak period and the fishing area of the Norwegian mackerel purse seine fishery has changed considerably due to market situations. The Norwegian reference fleet was established to get better and continuous sampling from all the Norwegian fisheries. A total of 34 vessels are contracted and the crew trained to conduct sampling of the catches. The fleet includes both offshore and coastal vessels and since 2003 the number of purse seine vessels has increased from one to five. In order to investigate if the changes in the mackerel fishery will affect the representativeness of the data from the reference fleet we use data from the vessel monitoring system, landing statistics and sampled data from the reference fleet. We compare the landings per trip of the total fleet with the reference fleet, and look at the spatial and temporal overlap for the time period 2006– 2007. Keywords: fisheries dynamics; mackerel; purse seine fishery; reference fleet; representativeness