Athens ’10

Workshop on Egg Production Methods for Estimating Fish Biomass

Organized by FRESH and ICES

10-13 March 2010



Athens, Greece

A workshop for researchers working on egg production methods for estimating fish biomass was hold March 10-13, 2010, in Athens, Greece, hosted by the Institute of Marine Biological Resources, Hellenic Centre for Marine Research (HCMR). This workshop was organized by the COST Action FA0601 “Fish Reproduction and Fisheries” (FRESH) and the International Council for the Exploration of the Sea (ICES).


The spawning stock biomass (SSB) of an exploited species is an important variable in the management of fisheries. Egg production surveys provide a method of estimating SSB independent on any data on commercial catches. In essence, three egg production methods are currently applied: (i) the Annual Egg Production Method, AEPM Lockwood et al., 1981), (ii) the Daily Egg Production Method, DEPM (Parker, 1980), and (iii) the Daily Fecundity Reduction Method, DFRM (Lo et al., 1992). SSB estimates based on egg production methods have been used to validate age based population methods (Horwood, 1993; Armstrong et al., 2001) or as direct assessments of biomass (e.g., when the effort data were not available from commercial vessels). In recent years, a large number of applications have been developed all over the world (Stratoudakis et al., 2006).

This Workshop covered advances and state of the art in the application of egg production methods to major pelagic stocks and to some demersal stocks. It considered several case studies such as:

  • Triennial ICES mackerel-horse mackerel survey
  • Irish Sea and Baltic cod comparison of DFRM, DEPM and AEPM
  • North Sea plaice SSB assessment with AEPM
  • DEPM for sardines and anchovies
  • DEPM application to European hake


The objectives of the Workshop were to:

  • Assess the strengths and problems of the different egg production methods in different situations/case studies
  • Produce a list of recommendations for the application of each method
  • Identify short term and long term research needs to improve precision and accuracy of SSB.
The Workshop was organized in four thematic sessions addressing reproductive biology/ecology, laboratory analyses, survey design, and statistical methods/models.
Workshop themes and keynote speakers:
Theme session 1   Improvements in biological and ecological knowledge for the application of egg production methods.
Keynote Speaker: Mike Armstrong (UK)
Conveners: Peter Witthames (UK) and Stelios Somarakis (Greece)
Theme session 2 Laboratory methods and techniques to determine egg and adult parameters
Keynote Speakers: Hilario Murua (Spain) and Clive Fox (UK)
Conveners: Cindy van Damme (Netherlands) and Andrés Uriarte (Spain)
Theme session 3 Survey design and sampling methods for ichthyoplankton and adults
Keynote Speaker: Pierre Pepin (Canada) and Dave Reid (Ireland)
Conveners: Miguel Bernal (Spain) and Cindy van Damme (Netherlands)
Theme session 4 Statistical methods to estimate egg and adult parameters and spawning stock biomass
Keynote speakers: Nancy Lo (USA) and Yorgos Stratoudakis (Portugal)
Conveners: Mark Dickey-Collas (Netherlands) and Miguel Bernal (Spain)

Scientific steering commitee

  • Stylianos Somarakis (HCMR, Greece)
  • Cindy van Damme (IMARES, Netherlands)
  • Peter Witthames (UK)
  • Andrés Uriarte (AZTI, Spain)
  • Miguel Bernal (IEO, Spain)