Improved methodology for cod age estimation (DECODE) (38120)

Project Details


The objective of this project is to develop and implement an objective method for the age-determination of Eastern Baltic cod. The assessment for Eastern Baltic Cod (Sub-divisions 25-32) has presented a number of problems in recent years. The key problem is the severe inconsistencies in age determination which affect both the catch-at-age and the survey data.

The methods to be developed within this project are based on the use of otolith biometrics. This procedure has proven successful in other stocks with age-reading problems. The data series on commercial and survey catch length distributions, otolith biometrics and biological parameters (collected for ICES Study Group on Ageing Issues in Baltic Cod (SGABC)) will be extended back as far as 2000.

Mixture and conditional models to estimate age structure for a given component in stock assessment will be developed as statistically robust approaches to age-determination. Based on this new method, the historic catch and survey data will be reconstructed.

The primary focus is on data for routine single-species assessments, but data for multi-species assessments will also be updated where possible.

The project is coordinated by DTU Aqua.

Research area: Marine Living Resources
Effective start/end date01/01/200731/12/2009

Collaborative partners

  • Technical University of Denmark (lead)
  • German Federal Research Centre for Fisheries (Project partner)
  • Morski Instytut Rybacki w Gdynia (Project partner)
  • Latvian Fish Resources Agency (Project partner)
  • Swedish National Board of Fisheries (Project partner)
  • Cefas Weymouth Laboratory (Project partner)


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