Why we should look more closely at fish eggs

From 21 to 25 October 2024, participants from 11 European institutes from Portugal, Spain, Ireland, the Netherlands, Germany, Denmark, the Faroe Islands, Norway and the United Kingdom met in Bremerhaven for the ICES WKMACHIS (Workshop on Mackerel, Horse Mackerel and Hake eggs Identification and Staging). This workshop is essential for the quality assurance of next year's mackerel and horse mackerel egg survey, which will provide one of the most important indices for the stock assessment of these commercially important fish species by determining egg production.

Scientists and technicians carried out comparative sorting exercises on typical plankton samples from the survey area. In addition, comparative exercises on the species identification of fish eggs and the determination of the developmental stage of fish eggs were carried out to ensure the reliable identification of mackerel, horse mackerel and hake eggs in particular. Furthermore, the causes of incorrect identification of fish eggs and their developmental stages were discussed and the uncertainty for these determinations was estimated.

The workshop was successfully completed and the results show that the participants can reliably identify fish eggs at a high level. This is an important prerequisite for ensuring that next year's mackerel and horse mackerel egg survey produces again reliable results for the stock assessments.

For more information on the mackerel and horse mackerel egg survey click here.

If you have questions regarding this topic, feel free to contact Jens Ulleweit.