Line of action:

Marine ecosystems

Status:

Finalizado

Execution date:

2018

Total budget:

51.000 €

Amount of aid from the Biodiversity Foundation:

25.500 €

Sharks and rays are among the most endangered marine vertebrates on the planet.
Populations of certain species have declined to critical limits.
Overfishing is the main cause of this decline, with bycatch being especially relevant.
In Spanish ports alone, thousands of these animals are caught daily accidentally, discarded as discards.
This project aims to address the loss of biodiversity through the application of animal reproduction techniques, such as gamete cryopreservation and the control of reproductive cycles, to achieve the reproduction of elasmobranchs in captivity.

The main objective of the project is to test 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.

It has the following specific goals:

• Dissemination and awareness of the problem in the fishing sector as the main agent involved.
• Determination of sexual maturation status, sperm production cycles and sex steroid levels 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.

• Dissemination days for the agents involved: visits to fishermen’s guilds informing about the project and the ways of collaboration.
• Obtaining samples of specimens of the target species (Scyliorhinus canicula, Scyliorhinus stellaris, Galeus melastomus, Raja montagui) from fishing discards.
• Extraction of sperm from the target species by catheter, abdominal massage or necropsy.
• Study of the physicochemical parameters of the seminal plasma of the sperm, emphasizing the pH, osmolarity and the ratio of ionic compounds of the same, following previous studies.
• Study of the quality of the sperm obtained through evaluations of sperm motility, morphology and viability prior to its preservation in the short and long term.
• Development and testing of diluents and freezing media for short- and long-term preservation of sperm.
• Study of sperm quality after short- and long-term preservation through evaluations of sperm motility, morphology and viability.
• Histological preparation of gonad (ovary/testicle) samples obtained from the animals obtained from the fishermen involved for the determination of the state of sexual maturation.
• To establish the reproductive cycle of males and the optimal time for sperm sample collection by correlating hormone levels, sperm maturation status, and sperm quality.
• Dissemination of results to the general public and education sector, the scientific sector and public authorities.

• Different trials have been carried out on the management of reproduction and cryopreservation techniques with elasmobranchs, specifically with specimens of various species of sharks and rays from trawling discards in collaboration with the fishermen’s guilds of the Valencian Community.
• A total of 160 samples have been obtained, of which 98 corresponded to males.
• It has been possible to extract sperm samples from a total of 91 specimens of three of the four species under study, being 56 specimens of catshark, 23 specimens of olayo and 12 specimens of painted ray.