Economic Improvement of Artisanal Fishing by Studying the Survival of Discarded Plectorhinchus mediterraneus

Abstract

Europe calls for the end to fisheries discards, which means bringing all caught fish (subject to minimum sizes or quotas) to land. This decision is beneficial to the ecosystem, since it forces the selectivity of the fishing gears to improve. However, artisanal fishermen find themselves in a vulnerable situation where their subsistence depends on catches with small profit margins. An exemption to this landing obligation exists, as it is also ruled that those animals whose survival is scientifically guaranteed may be returned to the sea. Here we study the survival of Plectorhinchus mediterraneus captured by hookline and gillnet, as well as their physiological recovery. Survival exceeds 93% in both cases. The physiological assessment of primary (cortisol) and secondary (energy mobilization, acid-base and hydromineral balance, and immune system) stress responses indicates that surviving animals are able to recover after fishing. Thus, we propose the optimal size of capture of this species to achieve greater economic benefit. For this, we rely on the prices according to size in recent years, as well as on the growth curves of the species. In this way, by releasing fish of less than 1 kg, the current benefits could be multiplied between 2.3 and 9.6 times. This pilot study lays the groundwork for regulating artisanal fisheries through scientific data related to survival of discards along with information on the sale prices.

Assessing Chronodisruption Distress in Goldfish: The Importance of Multimodal Approaches

“…On the other hand, the randomly fed fish took significantly longer to leave the wall zone for the first time on days 3-4 and 45-46 (Figure 5a,b). These RF fish also entered the open field zone less frequently (Figure 5c,d; significantly on days 3-4) and spent less time there than the controls (Figure 5e,f; significantly on days [45][46]. However, the RF fish showed no significant differences regarding the latency to central area (object approach).…”

“…Plasma cortisol was measured in duplicate as previously reported [46]. Briefly, 3N HCl was added 1:1 to samples and allowed to stand for 10 min at room temperature.…”