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On the occasion of Regulation (EU) No. 1380/2013, on the landing obligation, it is proposed to characterise the survival of rays caught by trawling in order to achieve their exemption. They are especially vulnerable to carryover due to the characteristics of their life cycle, since they have slow growth, late sexual maturity and low fertility. They are considered as choke species, being a limiting factor for this type of fisheries where bycatches are inevitable due to how non-selective this gear is. As described in the European Parliament, these species can lead to boats having to moor without exhausting the quota they have for their target species, causing great economic losses for the sector. Therefore, with these premises, it is necessary to study alternatives that reduce landings.

Specific objectives:

It is proposed to evaluate the physical and physiological recovery capacity of the most captured rays in the Gulf of Cadiz –Raja clavata and Leucoraja naevus- to characterize survival in an exhaustive way. To this end, the multidisciplinary methodology that has been established in the previous projects (SUREDEPAR and DISCARLIFE I) will be used, combining fisheries biology and animal physiology. Survival will be assessed in the short term, as well as their physical recovery, by analysing the vitality, reflexes and wounds of the animals after fishing and after different recovery times. At the same time, the physiological responses to stress caused by fishing will be studied, as they have been developed in the two projects mentioned above. Finally, it is suggested that the sector should deal directly with the sector to meet their needs in the face of the regulations to evaluate whether they can be incorporated, as well as training with them to comply with them.

The results of the DISCARDLIFE II project, carried out between December 2020 and January 2022, show high probabilities of survival of captured specimens of Santiago stingray in the warmest months of the year, with high probabilities being considered those greater than 50%. Likewise, it has been observed again how the decrease in temperature increases the chances of survival.

Regarding physiological responses to capture, it has been described with various stress biomarkers how the recovery of surviving animals occurs within the first 12 hours.

However, the most remarkable thing about this project has been the direct contact with the fishing sector. Not only in the shipments made with them, but also through various meetings and conferences, alliances have been created to continue with this line in the future.

Because the number of specimens captured on each outing has not turned out to be fully representative, these studies should be repeated in the future.