FAO have produced the mesopelagic fish guide and has been published online, you find it here!

This identification guide was conceived and supported by the EAF-Nansen Programme
“Supporting the Application of the Ecosystem Approach to Fisheries Management considering
Climate and Pollution Impacts”, in close collaboration with the FishFinder Programme of the
Marine and Inland Fisheries Branch (FIAF), Fisheries and Aquaculture Department, Food and
Agriculture Organization of Identification guide to the mesopelagic fishes of the central and south east atlantic ocean the United Nations (FAO).