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Sharks and rays are species that are among the most endangered marine vertebrates on the planet, with some of their populations having declined to critical limits. Threats such as overfishing are some of the main causes of this decline, with bycatch being especially relevant. This problem also occurs in Spanish ports where thousands of these animals can be accidentally caught daily, which are then discarded as discard. Given this context, the project has wanted to address the loss of biodiversity through the application of animal reproduction techniques, such as the cryopreservation of gametes and the control of reproductive cycles in species such as the catshark (Scyliorhinus canicula), the olayo (Galeus melastomus) and the painted ray (Raja montagui), to achieve the reproduction of elasmobranchs in captivity in the Valencian Community.

The main objective of the project has focused on testing the effectiveness of techniques used in assisted reproduction, to obtain viable gametes from sharks recovered from fishing discards and to be able to apply the knowledge learned to species that have a compromised conservation status.

Specifically, the initiative has pursued the following objectives:

• To disseminate and raise awareness in the fishing sector about this problem as it is the main agent involved.
• To determine the state of sexual maturation, sperm production cycles and levels of sex steroids in animals obtained by fishing activity.
• Develop and evaluate techniques to carry out short- and long-term maintenance of semen extracted from animals obtained by fishing activity.
• Dissemination of the results obtained within the framework of the project.

• Carrying out dissemination days in the Valencian Community to promote collaboration with fishermen’s guilds.
• Obtaining at least 20 male specimens to obtain sperm samples from each of the four target species; catshark (Scyliorhinus canicula), olayo (Scyliorhinus stellaris), alitán (Scyliorhinus stellaris) and painted ray (Raja montagui) from fishing discards from fishing ports in the Valencian Community.
• Extraction of sperm from the target species of the project by catheter, abdominal massage or necropsy.
• Analysis of the physicochemical parameters of the seminal plasma of the sperm.
• Evaluation of sperm quality through evaluations of motility, morphology (size and shape of spermatozoa) and sperm viability (number of live spermatozoa even if they do not move) prior to their conservation in the short and long term.
• Preparation of diluents and freezing media (based on the results of the previous action), for the preservation of sperm in the short and long term, respectively.
• Analysis of freezing media to evaluate sperm motility, morphology, and viability after short- and long-term sperm freezing to determine its efficacy.
• Dissemination of the results obtained aimed at the general public and teaching through talks and specialized publications.

• During the execution of this project, different trials have been carried out on the management of reproduction and cryopreservation techniques with elasmobranchs, specifically with specimens of catshark (Scyliorhinus canicula), olayo (Scyliorhinus stellaris), and painted ray (Raja montagui) from trawling discards in collaboration with the fishermen’s guilds of the Valencian Community.

• A total of 160 sperm samples have been obtained from three of the four target species under the project; 97 specimens of catshark, 40 specimens of olayo and 23 specimens of painted stripe. Finally, it has not been possible to obtain accidental catches of finlar (Scyliorhinus stellaris) specimens due to a biological shutdown of fishermen in April 2019 (trawlers stop carrying out their activity in order to recover fishing resources).

• The initiative, which has had the collaboration of the Oceanogràfic of Valencia in some actions, has allowed certain protocols to be applied by the centre’s staff after having been part of the team that has taken samples. In the same way, the experience of the center’s team has made it possible to improve the techniques for obtaining samples.

• At the same time, the transfer of knowledge has also been promoted thanks to the collaboration with visiting researchers from the Research Institute of Fish Culture and Hydrobiology, in the Czech Republic, which has made it possible to share the sperm extraction protocols developed by the team from the Polytechnic University of Valencia, together with the mobility analysis protocols developed by the Czech research team.

• For its part, the project, which has worked on these three marine species with the aim of achieving techniques that can be used for ex situ conservation protocols (outside their natural habitat) in the future, has achieved results that suggest that instrumental techniques and protocols could be extrapolated to many other species of sharks and rays.

• Finally, thanks to the initiative, tools have been developed that increase knowledge about reproductive anatomy and physiology in elasmobranchs such as; the extraction of sperm in different species of sharks and rays, the development of protocols to analyze the sperm obtained; the development of means for sperm maintenance, and the development of biometric protocols and information collection to estimate the reproductive stages of these species in the natural environment.