Duration: 23 September to 7 October 2025

Area: North Sea

Purpose: International Herring Larval Survey (IHLS)

The 494th voyage of the Walther Herwig III is part of the International Herring Larvae Survey (IHLS). These surveys shall regularly record the abundance and distribution of herring larvae in the spawning grounds of the North Sea herring stocks. They are coordinated by the International Council for the Exploration of the Sea (ICES) and have been organised in this form since 1972. In addition to Germany, the Netherlands and, for the first time, Scotland are also involved in the IHLS. The results form an important basis for stock assessment and are used to determine the scientific catch quota recommendation.

On this cruise, spawning areas around the Orkney and Shetland Islands and off the west coast of the United Kingdom will be investigated. The cruise provides the German contribution to the herring larval survey in the northern North Sea and covers the main spawning sites of the autumn spawning North Sea herring stocks in terms of time and space. In addition, herring larvae are sampled to analyse the fine structure of their otoliths (ossicles).