Identifying Persistent Hot Spot Areas of Undersized Fish and Crustaceans in Southern European Waters: Implication for Fishery Management Under the Discard Ban Regulation

Abstract

The recent establishment of the “landing obligation” under the reformed EU Common Fishery Policy has the twofold objective of reducing the excessive practice of discarding unwanted catch at sea and encouraging more selective and sustainable fisheries. Within this context, the awareness of the spatial distribution of potential unwanted catches is important for devising management measures aimed to decrease discards. This study analyzed the distribution of Hot Spot density areas of demersal fish and crustaceans below the Minimum Conservation Reference Size (MCRS) in four different southern European seas: continental Portuguese coast, Catalan Sea, South of Sicily, Liguria and northern Tyrrhenian Seas using both bottom trawl survey data and information on the spatial distribution of commercial fisheries. Critical areas for discarding were identified as zones where the highest densities of individuals below MCRS were consistently recorded throughout a series of years. Results clearly showed a patchy distribution of undersized individuals in each investigated area, highlighting the overlap between high density patches of both discards and fishing effort. The present findings provide a relevant knowledge for supporting the application of spatial-based management actions, such as the designation of Fisheries Restricted Areas (FRAs), in order to minimize the by-catch of undersized specimens and improve the sustainability of demersal fisheries.

Seasonal Trophic Ecology and Diet Shift in the Common Sole Solea solea in the Central Adriatic Sea

“…Since the Northern-central Adriatic Sea is one of the most intensively fished areas, especially by trawlers [ 85 ], and since species like Engraulis encrasicolus and Sardina pilchardus are among the main species of pelagic fishes discarded in this basin [ 26 ], they may not naturally be a large part of the diets of common soles. This supports the hypothesis that common soles can feed opportunistically on bycatch, and this could also explain the disintegrated status of these prey since they are consumed above discard grounds [ 49 , 86 ].…”

Identifying Priority Conservation Areas of Largehead Hairtail (Trichiurus japonicus) Nursery Grounds in the East China Sea

“…In this way, the spatial distribution of nursery grounds can be more flexibly compared under the same scale, making it possible to distinguish whether there are unique spatial processes or whether the spatial structure has changed over time. Compared to the geostatistical aggregation curve (Colloca et al, 2009;Tamdrari et al, 2010) or the Getis-Ord hotspot analysis (Colloca et al, 2015;Zacher et al, 2018;Milisenda et al, 2021), the suitability index analysis does not require complex calculation but lacks statistical interpretations and objectivity in the hotspot classification criteria. In this study, since the spatial distribution pattern of juvenile largehead hairtail was inter-annually stable with slight variations in the southern part of the ECS, the persistence index could be used for nursery grounds identification.…”

How Can We Reduce the Overexploitation of the Mediterranean Resources?

“…Since undersized fishes of many large-sized species, such as M. merluccius, are highly vulnerable to the minimum mesh size enforced in the Mediterranean (40 mm square or 50 mm diamond) (Brčić et al, 2018;Mytilineou et al, 2018) and a further increase of the mesh size would lose shrimps, cephalopods, and medium-sized fish, the exploitation pattern can be enhanced through: (i) increasing the trawl net selectivity by adopting grids and separators that allow the undersized fish to escape (Coll et al, 2008;Massutí et al, 2009;Aydın and Tosunoglu, 2011;Vitale et al, 2018b); (ii) delaying the size/age of the first capture of juveniles through spatial and/or temporal closures to fisheries when and where the juveniles aggregate in order to improve the fraction of fish reaching sexual maturity (Caddy, 1999(Caddy, , 2009Fiorentino et al, 2003;Garofalo et al, 2011;Colloca et al, 2015;Despoti et al, 2020;Mytilineou et al, 2020;Milisenda et al, 2021); or (iii) a combination of the two approaches.…”