In the ex situ conservation of chondrycthyan species, successful reproduction in aquaria is essential. However, aquatic species often exhibit reduced reproductive success under human care. Different factors, including water temperature, nutrition, and intrinsic genetic and epigenetic elements, influence their fertility. Conventional sperm analyses do not provide insights into the functional competence of semen. Therefore, proteomics is gaining relevance, increasing a better understanding of male physiology. In this study, we investigated the proteomic profiles of seminal plasma and spermatozoa from small-spotted catsharks in two different environments: natural environment and aquarium environment.