Aspetti dell'alimentazione di alcune specie ittiche batiali del Canale di Sicilia: Aristaeomorpha foliacea, Nezumia sclerorhynchus, Coelorhynchus coelorhynchus e Hymenocephalus italicus

Il gruppo dei Crostacei Decapodi comprende specie molto eterogenee per quanto riguarda la posizione occupata nei livelli trofici: vi sono rappresentate infatti specie necrofaghe, detritivore, nonchè attive predatrici, cosicchè ci sembra di grande interesse indagare il ruolo svolto da una specie di ingente valore commerciale - l'Aristaeomorpha foliacea - nell'ambito delle reti trofiche batiali. Esistono alcuni studi analoghi, riguardanti però Aristeus antennatus, effettuati in diverse aree mediterranee (acque spagnole, Mar Ligure); si è pensato dunque di condurre, parallelamente ad una ricerca sull'alimentazione di alcuni Selaci che è stata avviata a partire dal IX TRAWL survey (ved. ID/W.PR/CP-GB-MG-GD-FB/1/0690/DRAFT), lo studio dei contenuti stomacali di A. foliacea catturata durante le campagne di pesca organizzate dall'ITPP, a partire dal X survey. Per conoscere meglio anche i rapporti preda - predatore e/o di competizione tra questa specie ed altre presenti nello stesso ambiente, oltre ad usufruire delle informazioni provenienti dal parallelo programma sui Selaci, si è pensato di studiare la dieta di tre Teleostei Macruridi comunemente presenti sugli stessi fondi di pesca degli Aristeidi: Nezumia sclerorhynchus, Coelorhynchus coelorhynchus e Hymenocephalus italicus

Multiple paternity and hybridization in two smooth-hound sharks

Multiple paternity appears to be a common trait of elasmobranch mating systems, with its occurrence likely driven by convenience, due to females seeking to minimize the stress of male harassment. Here we use molecular markers to analyse the frequency of multiple paternity in two related viviparous sharks, Mustelus mustelus and Mustelus punctulatus. We first applied molecular methods to assign pregnant females, embryos and additional reference adults (N\u2009=\u2009792) to one of the two species. Paternity analysis was performed using a total of 9 polymorphic microsatellites on 19 females and 204 embryos of M. mustelus, and on 13 females and 303 embryos of M. punctulatus. Multiple paternity occurs in both species, with 47% of M. mustelus and 54% of M. punctulatus litters sired by at least two fathers. Female fecundity is not influenced by multiple mating and in 56% of polyandrous litters paternity is skewed, with one male siring most of the pups. Genetic analyses also revealed hybridization between the two species, with a M. punctulatus female bearing pups sired by a M. mustelus male. The frequency of polyandrous litters in these species is consistent with aspects of their reproductive biology, such as synchronous ovulation and possible occurrence of breeding aggregations

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

Commercial and non-target species of deep water trawled muddy habitats on the Maltese continental shelf

Prior to joining the European Union, Malta operated a 25nm Exclusive Fishing Zone that was retained as a Fisheries Conservation Zone (FCZ) following EU membership. The present study was conducted in this FCZ as part of the ongoing MEDITS trawl survey programme. Otter trawl samples were collected from muddy bottoms at depths of 100-300m. The catch from each haul was sorted into commercial and non-commercial components, and fauna were identified and counted. Samples for analyses of infauna and sediment characteristics were collected using a 0.0625m² capacity box-corer. Macrofaunal abundance data for the stations were analysed using ordination techniques (nMDS) and relationships between environmental variables and faunal assemblages were explored by superimposing individual variables on the two-dimensional nMDS plots. The analyses clearly separated the commercial species into two distinct groups of assemblages that seemed to be defined principally by depth: those from inshore and south-eastern stations (depth range 100-250m) and those from north-western stations (depth range 250-300m). The non-commercial species showed a similar pattern with assemblages from inshore stations grouping together; however, the offshore stations had a greater variability in non-target species composition, especially for infauna. For the offshore stations, geographical position seemed to be important since stations off the north-western coast of the Maltese islands grouped separately from those off south-eastern Malta.peer-reviewe

smartR: An r package for spatial modelling of fisheries and scenario simulation of management strategies

Abstract Overfishing or exploitation patterns with high juvenile mortalities often negatively impact demersal fish stocks. Meanwhile, the increased availability and diffusion of georeferenced information is propelling a revolution of marine spatial planning. A spatial‐explicit approach to the management of fishing effort should protect the Essential Fish Habitats and minimize the impact of trawlers on areas where juveniles of commercial species concentrate. The smartR package is a data‐driven model that implements the Spatially explicit bio‐economic Model for Assessing and managing demeRsal Trawl fisheries to edit and format the raw data; construct and maintain coherent datasets; to numerically and visually inspect the generated metadata; to simulate management scenarios and forecast the possible effects in terms of resources status and economic performances of the fleets. Explicit inclusion of the spatial dimension is essential to improve the understanding of the fishery system, and to enhance the ability of management plans to improve stocks statuses

Site fidelity of Hippocampus guttulatus Cuvier, 1829 at Mar Piccolo of Taranto (Southern Italy; Ionian Sea)

AbstractLack of detailed knowledge on ecological niche, life cycles, spatial distribution, reproductive biology and space use strongly affects the selection of useful tools and measures in the conservation of threatened marine species. Especially for sedentary and slow species, behaviour and movement capacities are supposed to be the most important functional traits. Indeed, behavioural variability concerning available space and the close presence of individuals is considered a crucial trait for the population dynamics assessments, especially when disturbances of various causes are present in the environment. The present study aimed to investigate the site fidelity and degree of movement of Hippocampus guttulatus, an emblematic and threatened Mediterranean seahorse species. With this aim, a number of seahorses were tagged and monitored throughout two years within a limited area of the lagoon of Mar Piccolo of Taranto (Southern Italy). The studied individuals were initially morphometrically measured for size, sex and life-cycle stage and subsequently monitored through repeated four-month surveys each year. Obtained results indicated high site fidelity regardless of habitat type. Movement pattern was in line with the data on congeneric species, although values were slightly higher. The analyses showed differences in movement degree among different sexes and life-cycle stages and indicated greater mobility of adult females compared to males and juveniles. The investigated parameters showed a great variability suggesting that even small-scale environmental factors can influence the species mobility. Finally, a change in the population structure has been observed, with the loss of large individuals in 2016 and reduced recruitment in 2017. These findings indicated the possible presence of stressors that could lead to the alteration of the seahorse population at Mar Piccolo of Taranto

Ontogenetic trophic segregation between two threatened smooth-hound sharks in the Central Mediterranean Sea

Elasmobranchs are among the species most threatened by overfishing and a large body of evidence reports their decline around the world. As they are large predators occupying the highest levels of marine food webs, their removal can alter the trophic web dynamic through predatory release effects and trophic cascade. Suitable management of threatened shark species requires a good understanding of their behaviour and feeding ecology. In this study we provide one of the first assessments of the trophic ecology of the \u201cvulnerable\u201d smooth-hounds Mustelus mustelus and M. punctulatus in the Central Mediterranean Sea, based on stomach contents and stable isotope analyses. Ontogenetic diet changes were addressed by comparing the feeding habits of three groups of individuals: juveniles, maturing and adults. Our results highlighted that the two species share a similar diet based mostly on the consumption of benthic crustaceans (e.g. hermit crabs). Their trophic level increases during ontogeny, with adults increasing their consumption of large-sized crustaceans (e.g. Calappa granulata, Palinurus elephas), cephalopods (e.g. Octopus vulgaris) and fish (e.g. Trachurus trachurus). Our results provide also evidence of ontogenetic shifts in diet for both species showing a progressive reduction of interspecific trophic overlap during growth. The results of this study contribute to improve the current knowledge on the trophic ecology of these two threatened sharks in the Strait of Sicily, thus providing a better understanding of their role in the food web

Urgent need for preservation of grapevine (Vitis vinifera L. subsp. vinifera) germplasm from small circum-Sicilian islands as revealed by SSR markers and traditional use investigations

Since the last decades grapevine germplasm is undergoing a process of rapid genetic erosion. This process is of particular concern in minor circum-Sicilian islands, because of the sharp reduction of the cultivated surfaces and the shift of their economy from agriculture to tourism. Aiming at valorising and preserving the surviving varieties we collected 185 accessions during several surveys since 2007. Six nuclear microsatellite markers were used for germplasm characterization, yielding 75 different genetic profiles. We found out that most genetic profiles (39) were not listed in national and international grapevine databases, confirming that the Sicilian minor islands represent underexplored hotspots of genetic diversity for grapevine. We also identified several synonymies, often due to geographic isolation, having 20 varieties at least two names. Conversely, 18 homonyms collectively indicated 34 genetically different accessions. Interviews with farmers provided information on current and past usage, and the origin and type of cultivation practices as well. The study also shows the urgent need for preservation of local grapevine germplasm, due to the disappearance of the elder caretakers of these traditional varieties. For rare germplasm preservation most part of the collected grapevine cultivars were introduced in an ex situ collection field