I am standing on the shoulders of giants...
Thanks to all those, deceased or still thriving, who developed and refined the methods decribed here and who produced all those data required to validate and to improve them. Many colleagues contributed to the the initial version and are involved in the continuous improvement of this handbook. I am indebted especially to:

- The late John Gage,
  Dunstaffnage Marine Laboratory

- Johan Craeymeersch
  Netherlands Institute for Fisheries Research

- Olaf Heilmayer
  AWI Bremerhaven