jats:pHundreds of millions of people on the planet are affected by malnourishment. This contributes to the vulnerability of large swaths of the population worldwide. Children under five years old and adolescent girls are especially disproportionately vulnerable to diseases and even death in less developed countries. Today, by providing a substantial share of global protein intake, as well as fatty acids and micronutrients, fisheries contribute to global food security. As fish stocks in the upper sea levels are increasingly over-exploited, there is a surge in discussion on the potential contributions of deep-sea fisheries for global food and nutrition security. Some mesopelagic fishes show potential in providing important nutrients. Another way of supplying food security might be in using mesopelagic fish as fish feed. However, fishing in the mesopelagic zone could lead to severe ecological repercussions, especially because the impact on the biological carbon pump is uncertain. This paper highlights and juxtaposes different perspectives regarding exploitation pathways of the fish riches of deep seas, and reviews best practice model projects that deal with uncertainties related to fishery management in the mesopelagic zone. The review concludes that due to the essential role of the mesopelagic zone in the global biological carbon pump and complex interaction patterns between pelagic and mesopelagic species, exploitation of the fish riches of the mesopelagic zone must be based on comprehensive data and rigorous analyses. In the face of the current uncertainty on the respective mechanisms, the authors endorse an international moratorium on deep-sea fisheries and/or the rather small-scale exploitation of mesopelagic biomass.</jats:p>