1987 - 2009 Centre for Environment, Fisheries & Aquaculture Science (Cefas) Blackwater Herring Survey (FSS: INA K HER)

A series of cruises carried out from 1989 to 2009 each November on the INA-K in the Thames Estuary. The aims of which were to assess the state of herring ( Clupea harengus ) stocks through measurements of length samples and by ageing a stratified selection of fish. The latter was also to determine the stock split between North Sea and Thames fish as there is a great deal of mixing of stocks in the area. Stock identification was done by a combination of first year growth observed in the otolith and the maturity stage of the fish.