Sandeels are small eel-like fish that is laterally compressed and without swimbladder that swim in large shoals and inhabit areas with specific sandy substrate into which they burrow. Sandeels are distributed in coastal and shallow open-ocean waters throu ghout the North Sea, but the geographical distribution is very patchy as they are restricted to such specific substrat.
The lesser sandeel (Ammodytes marinus) is by far the most abundant sandeel species in the North Sea, and the abundance and lipid rich ness of the lesser sandeel make them to an extremely important component of the food webs in The North Sea. They provide a significant part of the diet for many top predators such as birds, seals and predatory fish, and they also support the largest fish ery in The North Sea with annual landings in the late 1990's exceeding one million tons. However, a huge reduction in the abundance of lesser sandeel in recent years has caused a dramatic decrease in the annual landings, and the spawning stock biomass has been estimated to be below Blim since 2001.
The current assessment of the lesser sandeel stock is done with the use of fishery dependent data only, but 'given the current dependency on the data from the commercial fishery and the potentially critically state of the stock, there is an urgent need to develop survey-based fishery independent indicators of sandeel stock development' ICES (2004).
The project will develop a fishery independent survey methodology to monitor the state and the recruitment to the stock,by combing modern multifrequency acoustic, new scientific catch equipment for buried sandeel and adaptive survey