Survey : INA K 2/98 (part of Blackwater Herring Survey (FSS: INA K HER))

This survey was undertaken by Cefas as part of the 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.

Survey took place between 09/11/1998 and 20/11/1998 on INA K

Equipment used during this survey :

- Larson Sprat Trawl

Survey operations were undertaken on 39 stations

3 different species were caught on this survey

本项调查由Cefas执行，作为黑水鲱鱼调查（FSS：INA K HER）的一部分；自1989年至2009年，每年11月在泰晤士河口区域的INA-K号船上开展了一系列的巡航活动。调查的目的是通过测量长度样本和通过对分层选取的鱼类进行年龄鉴定来评估鲱鱼（Clupea harengus）种群的状况。此外，还旨在确定北海与泰晤士鱼类之间的种群分裂，因为该区域种群混合现象严重。种群鉴定是通过观察第一年耳石生长和鱼类的成熟阶段相结合的方法完成的。调查于1998年11月9日至11月20日在INA K号船上进行。此次调查使用的设备包括：拉森鳕鱼拖网。调查在39个站位进行，捕获了3种不同的鱼类。