Northwest Herring Acoustic Survey Report 2005

Abstract

The northwest and west coast herring acoustic survey programme was first implemented in 1994. Prior to this a larval survey programme was carried out between 1981 and 1986. The ICES herring working group (HAWG) identified the need for a dedicated herring acoustic survey in this area (Anon, 1993). The stock in this area is composed of a number of spawning components and spawning may extend from September through to March (Molloy et al, 2000). Commercial fishing has targeted the fish during spawning times, no summer matje fishery exists in this area. In VIaS, fishing has traditionally taken place in late December and continues until late February (winter spawners). Traditionally in VIIb, fishing is mainly concentrated on the later months of the year and would be concluded by the early part of the new year (Autumn spawners). The protracted spawning period of herring and the overlap between the two spawning socks in this area (October to February) means that it is difficult to design a survey that covers all spawning fish in one specific survey. A project is currently underway to describe stock structure and discrimination of herring around Ireland. The results of this project may have implications for the design of this survey and for the stock assessment. However, since 1994, acoustic surveys have been carried out, and currently are the only tuning indices available. The current survey makes up the 11th in the time series. The design and execution of this survey has evolved from summer feeding phase surveys, in the mid 1990s until its present winter spawning state.