Valutazione dell’impatto del settore della pesca sull’ecosistema marino - Indicatori ecosistemici (sezione V) Sub-area Geografica (GSA) 16 – Stretto di Sicilia Anno 2016

Il Programma Nazionale Italiano 2014-2016 di Raccolta Dati nel settore della pesca prevede, inter alia, la stima di cinque indicatori dell’impatto della pesca nell’ecosistema marino, in accordo con quanto riportato nell’appendice XIII della Decisione della Commissione del 6 novembre 200

Prvi nalaz mača srebrenjaka Trachipterus trachypterus Gmelin 1789 (Lampriformes) u Sicillijanskom tjesnacu

On July 7th 2018 a specimen of Mediterranean dealfish (Trachipterus trachypterus Gmelin 1789) was caught in the shallow waters of Selinunte (in the South-Western coast of Sicily) by trammel net. It was a female in maturing phase and the gonadosomatic index resulted as 1.1%. The specimen measured 1638 mm in total length and weighed about 2480 g. The estimated age through growth increments in vertebra was of 41 years. The finding of the Mediterranean dealfish in the Strait of Sicily might be linked to its spawning period during which it approaches the shallow waters. The present specimen represents the first record in the Strait of Sicily.Dana 7. srpnja 2018. uzorak mediteranskog dealfish (Trachipterus Trachypterus Gmelin 1789) je uhvaćen u plitkim vodama primorskog mjesta Marinella di Selinunte (na jugozapadnoj obali Sicilije) s troslojnom mrežom. Bila je to ženka u fazi sazrijevanja, a gonadosomatski indeks rezultirao je 1,1%. Uzorak je izmjeren 1638 mm ukupne duljine i težio je oko 2480 g. Procijenjena dob kroz povećanje rasta kralježaka bila je 41 godinu. Otkrivanje mediteranskog delfish u Sicilijskoj tjesnac mogao bi biti povezan s njegovim razdobljem mrijesta tijekom kojeg se približava plitkim vodama. Sadašnji uzorak predstavlja prvi zapis u Siciliji

Vulnerability of demersal fish assemblages to trawling activities: a traits-based index

Reducing the impact on vulnerable species through changes in fishing practices, such as the spatial or temporal avoidance of certain areas, is key to increase the ecological sustainability of fisheries. However, it is often hampered by the availability of sufficiently detailed data and robust indicators. Existing trawl surveys are a cost-effective data source to assess the vulnerability of fishing areas based on the quantities of vulnerable species caught. We developed a biological traits-based approach to the vulnerability of demersal assemblages using commercial trawl catch data. An expert-based approach identified a set of biological traits that are expected to condition the species' response to trawling impact and are combined to produce the vulnerability index ranked into four levels (low, moderate, high, and very high vulnerability). The approach was tested in four southern European fishing grounds showing evidence of over-exploitation, through catches being dominated by species of relatively low vulnerability to fishing impacts. The general distribution of species' biomass amongst vulnerability groups was highly homogenous across case studies, despite local differences in fishing fleet structure, target species and fishing depths. Within all areas the species with moderate vulnerability dominated and, in most instances, species of "very high" vulnerability were not recorded. Nevertheless, differences emerged when comparing the proportions of highly vulnerable species in the catches. Variability in vulnerability level of the catch was also observed at small spatial scales, which was principally explained by differences in habitat type and depth and, secondarily, by fishing effort. In fine mud in the shallower areas there was a higher presence of low vulnerable fauna. Furthermore, vulnerable organisms decreased in their presence in sandier substrates on the continental shelf. The spatial heterogeneity in assemblage vulnerability composition encourages the potential for adoption of this index in the spatial management of fishing grounds aiming at ensuring a sustainable exploitation by mitigating trawl impacts on the most vulnerable components of the demersal assemblages.MINOUW Horizon 2020 (Project ID: 634495); H2020-Marie Skłodowska-Curie Action MSCA-IF-2016 (Project ID: 743545)info:eu-repo/semantics/publishedVersio

Length-Weight Relationships of 52 Species from the South of Sicily (Central Mediterranean Sea)

The Length-Weight relationships (LWRs) of 52 species (14 never reported before) of fishes, crustaceans and cephalopods living on the shelf and upper slope off Southern Sicily are provided. Data were collected in the framework of the International bottom trawl survey in the Mediterranean (MEDITS) in the South of Sicily (Central Mediterranean), covering a time frame ranging from 2012 to 2019. Linear regressions were significant for all species (p < 0.05) with R-2 values ranging from 0.86 to 0.99. The intercept (a) of LWRs ranged from 0.0003 to 0.4677, while the slope (b) ranged from 2.1281 to 3.306. The Welch t-test, used to evaluate differences between the obtained LWRs with those reported in the literature, revealed that most of the LWRs (about 55%) reported in this study are in disagreement with those obtained previously by other authors from the Strait of Sicily. It is expected that the results obtained from this study will contribute to filling the knowledge gap of fish populations in this area and also assist fisheries scientists in future stock assessment studies

Stock status and potential yield of deep water rose shrimp (Parapenaeus longirostris, Lucas 1846) in the south-central Mediterranean Sea

This document summarises the data used, methods adopted and the results of the joint stock assessment carried out during the MedSudMed and CopeMed II Working Groups on Parapenaeus longirostris and related fisheries held in 2009 and 2010 in Malta and Italy respectively. The aim of this document is to describe the state of the stock of P. longirostris in the south-central Mediterranean Sea using data from Italy, Tunisia and Malta. The long term objective of this study is to provide the baseline for the establishment of a harmonised management regime for the deep water rose shrimp fishery in the south-central Mediterranean Sea. Overall, fishery dependent data from Italy, Malta and Tunisia for the first time were pooled together and jointly processed. The assessment was performed using length cohort analysis (LCA) and biomass and yield per recruits analyses as implemented in VIT4Win. Current mean fishing mortality and exploitation pattern were assessed using the steady state LCA on length frequency distributions (LFD) of 2007, 2008 and 2009 as well as the average 2007-2009 catches, raised to the total landings. Analyses were performed separately by keeping sex and fleet segments separate (i.e. Italy 12-24; Italy > 24; Tunisia; Malta) as first step. A sensitivity analysis was also carried out as implemented in VIT. The results are discussed in the view of providing robust technical advice for the management of national fisheries exploiting P. longirostris in the MedSudMed area taking into account the possible evolution of national fisheries. Some perspective for future joint activities to be carried out within the cooperative framework established by the FAO Projects are also presented.peer-reviewe

Exploring the feasibility of technological transfers of two by-catch reduction devices in the crustacean bottom trawling of the central Mediterranean

Introduction: Most Mediterranean fish stocks are overexploited owing to high fishing efforts and poor exploitation patterns. Demersal trawl fisheries are considered the most impactful fishery type because of the high quantities of unwanted catch that is then routinely discarded at sea. Methods: In the present study, two types of by-catch reduction devices (BRDs), that is a sorting grid (Grid-T45 40 mm) and a T90 50 mm codend, were compared to a typical commercial bottom trawl net (control) in terms of size structures and catch per unit effort to assess the effect of gear modification on the selectivity of crustacean fisheries in the central Mediterranean Sea. In particular, three randomly selected trawlers were involved in a paired hauls experiment fishing at the same time in the same fishing ground. Each trawler carried out four hauls per day during a 3-day campaign for a total of 36 hauls. The target species of the fishery is Parapenaeus longirostris (herein DPS), and the main commercial by-catch is Merluccius merluccius (herein HKE). Results: The results showed that the landing per unit effort (LPUE) of DPS was higher for Grid-T45 40 mm net, although it did not differ significantly from that of the control net. Conversely, the discard per unit effort (DPUE) of the control net was significantly higher than of both BRD configurations. For HKE, a slightly higher LPUE was recorded using the T90 50 mm codend compared to that of the control, but this result was not statistically significant. The lowest DPUE was found for the T90 50 mm codend, with significant differences compared to that of the control and Grid-T45 40 mm net. The catch comparison of the size structures analysed through generalised linear mixed models highlighted that the Grid-T45 40 mm net was more effective in catching adult DPS, whereas the T90 50 mm codend was more selective for adult HKE Discussion: In conclusion, although further studies should be carried out in future to test the performance of the BRDs in different areas and seasons, the investigated gear seems to be promising for reducing the catch of undersized individuals and contributing to mitigating the current overfishing of DPS and HK

Campagna di ricerca in mare: Sezione G – MEDITS 2012. Sub-area Geografica (GSA) 16 – Stretto di Sicilia

La campagna scientifica Medits, nell’ambito del Programma nazionale Italiano per la raccolta dei dati alieutici (Reg. CE n°199/2008 e n°665/2008), ha l’obiettivo generale di valutare la distribuzione, l’abbondanza e la composizione per taglia delle specie oggetto di pesca presenti nei mari Italiani. L’Istituto di ricerche per l’Ambiente Marino Costiero (IAMC), sede di Mazara del Vallo, del Consiglio nazionale delle Ricerche (CNR), effettua campagne di ricerca in mare nella GSA 16 (FAO, 2001) dello Stretto di Sicilia, tramite rete a strascico (trawl survey), sin dalla primavera del 1985, con l’obiettivo generale di studiare l’abbondanza ed i cicli vitali delle risorse demersali e di stimarne lo stato di sfruttamento

GRUND 2008 nella sub area geografica 16 (GSA 16, Stretto di Sicilia): relazione finale

Il progetto Grund, finanziato a partire dal 1985 dapprima dalla D.G. Pesca e Acquacolura del Ministero per le politiche agricole, alimentari e forestali (MIPAAF) con i fondi della legge 41, in seguito dal MIPAAF e dalla DG IV della Commissione Europea, ha l’obiettivo generale di valutare la distribuzione, l’abbondanza e la composizione per taglia delle specie oggetto di pesca presenti nei mari Italiani. L’Istituto di ricerche sulle Risorse Marine e l’Ambiente, Sezione di Mazara del Vallo di IAMC-CNR, effettua campagne di ricerca in mare nella GSA 16 (FAO, 2001) dello Stretto di Sicilia, tramite rete a strascico (trawl survey), sin dalla primavera del 1985, con l’obiettivo generale di studiare l’abbondanza ed i cicli vitali delle risorse demersali e di stimarne lo stato di sfruttamento

Towards more selective Mediterranean trawl fisheries: are juveniles and trash excluder devices effective tools for reducing undersized catches?

Mediterranean trawl fisheries are characterized by a critical combination of high fishing effort and low size at first capture for most commercial species. In this study we tested the use of sorting grids installed on bottom trawl nets to minimize the catch of undersized deep-water rose shrimp (Parapenaeus longirostris, DPS) and European hake (Merluccius merluccius, HKE). The catch of a traditional trawl net was compared with that obtained with the same net equipped with ad hoc designed juveniles and trash excluder devices (JTEDs) during an experimental survey. Three different JTEDs were tested: the first (G1-SM40) was built with a net of 40-mm square mesh; the second (G2-ST20) and third (G3-ST25) with vertical steel bars spaced 20 and 25 mm, respectively. The probability of retaining DPS and HKE by length class in trawl nets with and without JTED was analysed using generalized additive mixed models. With G1-SM40, the reduction of undersized individuals in the cod-end was about 60% and 44% for DPS and HKE, respectively. With G2-ST20, a 34% catch decrease of HKE individuals smaller than 20 cm total length was observed. A loss of marketable fractions of DPS was recorded with G1-SM40 (–25%) and G2-ST20 (30%). Finally, JTD G3-ST25 was efficient at reducing the catch of undersized specimens of DPS and HKE, but showed a higher loss of marketable fractions than the other JTEDs. Although further fishing trials would be required to maximize the sorting efficiency of the grids, the results obtained clearly indicated that grids can substantially reduce unwanted catches of undersized DPS and HKE in Mediterranean bottom trawl fisheries

Patrón de abundancia espacio-temporal de la gamba de altura, Parapenaeus longirostris, y de la cigala, Nephrops norvegicus, en las aguas mediterráneas europeas

The main characteristics concerning the distribution of two of the most important decapod crustaceans of commercial interest in the Mediterranean Sea, the deep-water rose shrimp, Parapenaeus longirostris, and the Norway lobster, Nephrops norvegicus, are studied in the European Mediterranean waters. The study is based on data collected under the MEDITS trawl surveys from 1994 to 2015 from the Gibraltar Straits to the northeastern Levantine Basin (Cyprus waters). The observed differences can be interpreted as different responses to environmental drivers related to the differing life history traits of the two species. In fact, N. norvegicus is a long-living, benthic burrowing species with low growth and mortality rates, while P. longirostris is an epibenthic, short-living species characterized by higher rates of growth and mortality.Se investigaron las características de la distribución de dos de los crustáceos decápodos más importantes a nivel comercial del mar Mediterráneo, la gamba de altura, Parapenaeus longirostris y la cigala, Nephrops norvegicus, en aguas mediterráneas europeas. El presente estudio se basa en datos recopilados en las campañas de pesca experimental de arrastre MEDITS, relizadas de 1994 a 2015 desde el estrecho de Gibraltar hasta la cuenca levantina nororiental (aguas de Chipre). Las diferencias observadas en el patrón de distribución se pueden interpretar como distintas respuestas a factores ambientales relacionados con los diferentes rasgos del ciclo vital de las dos especies. De hecho, N. norvegicus es una especie bentónica de vida larga, con bajas tasas de crecimiento y mortalidad, mientras que P. longirostris es una especie epibentónica de vida corta, caracterizada por tasas más altas de crecimiento y de mortalidad