WKMADE

True

Dolores Garabana Barro, Anders Thorsen

EOSG

dolores.garabana@ieo.csic.es, anders.thorsen@hi.no

Workshop on Mackerel Daily Egg Production

Workshop on Mackerel Daily Egg Production (WKMADE)
13–17 November 2023
Vigo, Spain

For a number of years there has been a debate whether mackerel can still be classed as a determinate spawner, or should they be reclassified as an indeterminate species. Work has been carried out by Working Group on Mackerel and Horse Mackerel Egg Surveys (WGMEGS) to try to answer this question. A thorough analysis of the information collected is now a necessity. It is expected that the workshop will refine the developed methodologies and clarify established calculations for these adult parameter estimation.

The group will:

Evaluate the lab procedures used to analyse adult ovary samples. This includes histology screening, staging of post ovulatory follicles (POF, for spawning fraction) and batch fecundity. Alternatives to POFfor the estimation of spawning fraction will be explored.
Look into the calculations of spawning fraction and batch fecundity, and derive a Daily Egg Production Method (DEPM) based estimates of Spawning Stock Biomass (SSB) for each of the four survey years, 2013 to 2022. The accuracy and precision of the newly derived time series of the DEPM method will be compared to the timeseries of the standard Annual Egg Production Method (AEPM).