Genetic diversity is fundamental to a species’ ability to adapt, evolve, andsurvive over time, while also providing essential services to humankind.In the context of food and agriculture, this diversity results from bothnatural evolution and artificial selection through domestication and geneticimprovement. Maintaining and restoring such diversity is critical to ensure thelong-term sustainability and adaptive potential of both wild and domesticatedspecies. Gene banking is one tool that is valuable in the conservation andmanagement of these genetic resources. This document provides technicalguidelines for the ex situ in vitro conservation of aquatic genetic resourcesfor food and agriculture, including finfish, shellfish, seaweed, and microalgae.As one of the strategic priorities of the FAO Global Plan of Action forthe Conservation, Sustainable Use and Development of Aquatic GeneticResources, ex situ in vitro conservation plays a role complementary to in situefforts of protected areas and live gene banks, contributing to the sustainablemanagement of aquatic biodiversity. However, compared to the crop andlivestock sectors, in vitro conservation of aquatic species is stillunderdeveloped, facing challenges such as the extremely broad diversityof species and physiology, lack of standardized protocols, inconsistentterminology, and limited reporting guidelines.The present volume aims to support policymakers, resource managers,conservationists, aquaculture producers, and researchers in advancing thedevelopment and application of in vitro conservation for gene banking andselective breeding.The guidelines provide an overview of current practices, with practicalinformation on existing methods (particularly cryopreservation), theestablishment and organization of gene banks, regulatory considerations,and cost implications. Technical elements, including examples of laboratoryprotocols, are included to support practitioners and to facilitate thedevelopment of new methods. Experiences from different parts of the worldshow how challenges are faced under different circumstances, and how theapproach provides tangible benefits.Progress in the ex-situ in vitro conservation of aquatic species and a broaderapplication of in vitro conservation technologies would significantly improvethe management of both wild and domesticated aquatic genetic resources.