Artificial reproduction involves collection and handling of gametes in a way that secures their quality and maximizes the fertilization outcome. In addition to initial sperm quality, numerous steps can affect the final result of fertilization, from the sperm collection process until gamete mixing (or co-incubation) when the spermatozoon enters or fuses with the oocyte. In this review, we summarize the whole process of sperm handling, from collection until fertilization for fish, penaeid shrimp, bivalve mollusks and marine mammals. To obtain sperm from captive animals, techniques vary widely across taxa, and include stripping by abdominal massage or testis surgical removal in fish, spermatophore collection in penaeid shrimps, gonadal scarification or temperature shock in bivalve mollusks, and voluntary collection via positive reinforcement in mammals. In most cases, special care is needed to avoid contamination by mucus, seawater, urine, or feces that can either activate sperm motility and/or decrease its quality. We also review techniques and extender solutions used for refrigerated storage of sperm across the aforementioned taxa. Finally, we give an overview of the different protocols for in vivo and in vitro fertilization including activation of sperm motility and methods for gamete co-incubation. The present study provides valuable information regarding breeder management either for animal production or species conservation.

Although a relatively high number of sperm quality biomarkers have been reported over the years in several fish species, sperm motility is nowadays considered the best biomarker for fish spermatozoa. The first scientific reports focusing on fish sperm motility date from a century ago, but the objective assessment allowed by computer-aided sperm analysis (CASA-Mot) systems was not applied to fish species until the mid-1980s. Since then, a high number of sperm kinetic parameters from more than 170 fish species have been reported in more than 700 scientific articles, covering a wide range of topics, such as sperm physiology, sperm storage, broodstock management, the phenomenon of sperm competition, ecotoxicology and understanding the life cycle of the species. The sperm kinetic parameters provided by CASA-Mot systems can serve as powerful and useful tools for aquaculture and ecological purposes, and this review provides an overview of the major research areas in which fish sperm motility assessment by a CASA-Mot system has been used successfully.