Ultrasound imaging analysis involves development of an effective combination of physical properties, equipment, instrument settings, and protocols. This review focuses on the application of ultrasonography to fish reproduction. The goal was to assemble a comprehensive reference data set to serve as a decision-enabling tool for potential users. The specific objectives were to (1) identify the ultrasound equipment, settings, and procedures used during examination, (2) review the fish handling procedures used during examination, and (3) review current data on sex identification and reproduction indices developed using ultrasonography. The 27 studies selected for inclusion in this review represent 21 fish species. Most (96%) of the studies reported the model name for the ultrasound unit, but only 19% reported the probe model. The most reported probe features were the frequency capability (96% of the studies) and array format (linear, sector, or annular; 81%). The majority of the studies (89%) did not report any of the control settings used. The combinations of handling and ultrasound procedures were variable even within the same species, and the majority (78%) of the studies included a form of restraint. None of the studies simultaneously integrated the use of unrestrained, unanesthetized, submersed fish with a submersed waterproof probe, which would enable the use of water as a transmission medium for ultrasound. Size, life stage, gonadal growth of reproductively active adults, and fish morphology influenced the ability to use ultrasonography for sex identification and the development and application of qualitative and quantitative reproductive indices. The utility of ultrasonography in fish reproduction has been repeatedly validated, and innovative indices for noninvasive use have been developed. However, this review identifies a clear lack of consistency in reporting of instrument settings and handling procedures and provides suggestions for standardizing the use of ultrasonography with aquatic species.

Cryopreservation in aquatic species in general has been constrained to research activities for more than 60 years. Although the need for application and commercialisation pathways has become clear, the lack of comprehensive quality assurance and quality control programs has impeded the progress of the field, delaying the establishment of germplasm repositories and commercial-scale applications. In this review we focus on the opportunities for standardisation in the practices involved in the four main stages of the cryopreservation process: (1) source, housing and conditioning of fish; (2) sample collection and preparation; (3) freezing and cryogenic storage of samples; and (4) egg collection and use of thawed sperm samples. In addition, we introduce some key factors that would assist the transition to commercial-scale, high-throughput application.