The publication of this book received financial support from the French Biodiversity Agency (AFB), now the French Office for Biodiversity (OFB) as manager of the funds of the Ecophyto II national action plan (AFB/2019-327 agreement). This book is a synthesis of a collective scientific assessment (CSA) requested jointly by the Ministries of Ecology, Agriculture and Research. It was produced by a group of scientific experts without prior approval by either the sponsors, INRAE or Ifremer. The present summary, taken from the extended report, is the sole responsibility of its authors.The documents associated with this assessment are available on the websites of INRAE (www.inrae.fr) and Ifremer (www.ifremer.fr).