Can the standard IBTS-MIK survey provide reliable data on herring recruitment and spawning locations? ...

No abstracts are to be cited without prior reference to the author. In February and March each year an IBTS-MIK survey is conducted in the North Sea and English Channel to estimate the number of herring larvae. The standard sampling utilises a MIK (2m mid-water ring trawl: 1.6 mm mesh size), which is designed to catch larger autumn spawned herring larvae. The MIK-recruitment index ignores larvae below 11 mm. However, in recent years the numbers of small larvae has increased due to the increased herring winter spawning component and a prolonged spawning season. The international herring larvae surveys (IHLS) use a Gulf VII high-speed plankton sampler (280 µm) for catching small, recently hatched larvae. This survey finishes too early for newly hatched larvae in February. ...