CE11015

In the Celtic Sea and VIIj, herring acoustic surveys have been carried out since 1989, and this survey is the 20th in the overall acoustic series or the seventh in the modified time series (i.e. conducted in October). The geographical confines of the annual 21 day survey have been modified in recent years to include areas to the south of the main winter spawning grounds in an effort to identify the whereabouts of winter spawning fish before the annual inshore spawning migration. Spatial resolution of acoustic transects has been increased over the entire south coast survey area. The acoustic component of the survey has been further complimented since 2004 by detailed hydrographic and marine mammal and seabird surveys