Towards the integration of ecophysiology with fisheries stock assessment for conservation policy and evaluating the status of the Mediterranean Sea.

Recent European Union (EU) regulations have been introduced to discourage the capture of undersized specimens with the aim of reducing the bycatch mortality imposed by commercial fisheries. We argue that we still lack accurate data regarding basic information required to properly implement these regulations for most Mediterranean ecosystems, including the true mortality imposed by fisheries, escape rates from fishing gears and the capability of specimens to survive following discard. We suggest that additional reliance on physiological biomarkers could assist in all aspects of the data collection required to support implementation of the EU discard ban (aka landing obligation), particularly in determining which species should receive special dispensation from this policy. Ideally, this new approach, here termed the 'Fisheries Environmental and Physiological Stress Analysis' (FEPSA), would become an important step for any fish stock assessment within the ecosystem approach to fisheries management and the recognition of Good Environmental Status, as established by the EU in the Marine Strategy Framework Directive (2008/56/EC). In particular, the main goal of FEPSA would be applying the study of physiological stressors to exploited stocks to estimate the so-called collateral fishing mortality, which includes the mortality experienced by fish that escape after interacting with fishing gears or that are discarded, with some degree of injury or physiological stress. The approach outlined here, which is described for bottom trawls but adaptable to any other type of fishing gear, is not a trivial undertaking but is a requirement for collecting the data required by recent EU fisheries policies. While we agree that the threats to marine biodiversity posed by fishing and associated discard practices require strong policy interventions, we emphasize that the research programs needed to support such initiatives, including the landing obligation, should be given equal priority. This is particularly true for Mediterranean fisheries, which are at a complex intersection of jurisdictional boundaries, numerous additional ecosystem threats including widespread pollution, thermal variation and hypoxia, and are historically understudied as compared to fisheries and species in more northern climates.

Microplastics occurrence in the Tyrrhenian waters and in the gastrointestinal tract of two congener species of seabreams.

In this work it is reported for the first time the characterization of microplastics from sea water samples and in two congener species of seabreams: Pagellus erythrinus and P. bogaraveo, Mediterranean fish species of great commercial importance. An experimental survey was conducted on May-June 2017 in the southernmost part of the Tyrrhenian Sea. Microplastics found in the sea water and in the grastrointestinal tract of two teleosts were characterized by Raman and IR spectroscopies. Microplastics found in sea water samples appeared in the form of fragments made of plastics of low and high density (PVC and LPDE). All the microplastics found in fish belonged to Nylon 66, typical fibers used in industry and in fisheries. Our findings highlighted the importance of further studies along the food web chain for a better understanding of the diffusion and possible consequences of this terrible threat.

The effectiveness of fish feeding behaviour in mirroring trawling-induced patterns.

The ability to observe and predict trawling-induced patterns at spatial and temporal scales that are relevant to inform realistic management strategies is a challenge which scientists have consistently faced in recent decades. Here, we use fish feeding behaviour, a biological trait easily impaired by trawling disturbance, to depict alterations in fish condition (i.e. individual fitness) and feeding opportunities. The benthivorous fish Mullus barbatus barbatus was selected as a model species. The observed trends of responses to trawling in prey species confirmed the effectiveness of a non-trawled zone in sustaining higher levels of diet diversity (e.g. quantity and quality of ingested prey) and fish condition values (e.g. morphometric and physiological Condition Index). Changes observed in fish prey selection confirmed the role of trawling disturbance in modifying the local soft bottoms community, producing alterations of prey availability that trigger shifts in fish diet. Trawling-induced feeding patterns, mirrored through stomach contents, can positively or negatively affect fish condition, the main driver of population dynamics in maintaining carrying capacity levels. Due to the widespread socio-economic value of the red mullet fishery, and the current exploitation status, evidence gathered by the proposed bottom-up trait based approach might inform future trawling adaptation strategies, and tailor spatial conservation measures supporting an Ecosystem-Based Fisheries Management.

Serological survey on Aujeszky's disease, swine influenza and porcine reproductive and respiratory syndrome virus infections in Italian pigs.

Aujeszky's disease (AD), Porcine reproductive and respiratory syndrome (PRRS) and Swine influenza (SI) are among the principal agents of respiratory diseases of pigs. The aim of the study was to determine the prevalence of antibodies to SHV-1, PRRSV and SIV in pigs reared in Sicily. An Enzyme Linked Immunosorbent Assay for the glicoprotein gE of pseudorabies virus, for PRRSV and for SIV was performed. Antibodies against gE of SHV-1 were detected in 171 serum samples (14.6%), whereas PRRSV antibodies occurred at a higher frequency than SHV-1 with 289 (31.1%) samples being positive. The seroprevalence of SIV was found to be 33.3%. This study demonstrated the circulation of ADV, PRRSV and SIV viruses in Sicilian swine population. This is the first report on this topics in Sicily.

Feline calicivirus strains isolated in Italy.

Feline Calicivirus (FCV) has been recognised as major oral and respiratory pathogen of cats. The high correlation among the field viruses and FCV-F9 serotype has represented the immunological bases for the employ of FCV-F9 serotype as a vaccine for calicivirosis in cats. The aim of this paper was to evaluate, by in vitro neutralization assays, the antigenic correlation among the vaccine F9 and FCV field strains isolated in Sicily (Italy) from cats showing clinical forms referable to calicivirus infection. The results confirm the low correlation between FCV-F9 strain and calicivirus strains spread in the feline population.

Tissue damage and haematophagia due to praniza larvae (Isopoda: Gnathiidae) in some aquarium seawater teleosts.

Over a 5 yr period, severe infestations due to Gnathia vorax larvae affecting different teleosts have been registered at the Civic Aquarium of Messina, Italy. Here, the damage caused by these parasites is evaluated from a macroscopical and histopathological point of view. We also attempt to evaluate the amount of blood sucked up by a single parasite and make some observations about the haematophagia. The histopathological changes confirm mucosal electrolytic failure as the main problem, even though the mean value of blood sucked up by a single parasite, about 1.9 mg, suggests that haematophagia may play an important role in the pathogenesis of such infestation. In conclusion, it was found that the G. vorax larvae caused 2-fold damage that was responsible for the death of the fish. Little by little, the parasitic problem was successfully removed by washing the tank, using fresh water rather than costly and dangerous chemotherapeutans.

Light and scanning electron microscopy observations on Gnathia vorax (Isopoda: Gnathiidae) larvae.

A large population of gnathid isopods (Crustacea) has been observed on sea water teleost fishes coming from the Civic Aquarium of Messina (Italy). Gnathiidae are parasite of fishes only at the stage of praniza, while adults are free living. Several teleosts, reared in captivity at the Civic Aquarium of Messina were sent for parasitological examination over a period of three years. Numerous parasites, identified as pranizae of Gnathiidae, were found on dorsum, on dorsal, pectoral and caudal fins, as well as in oro-pharyngeal cavity and gills of the affected fishes. The cranial part of an exuvie of adult male belonging to Gnathia sp. was also found on the floor of the tank. Because adult parasites are rarely detected in the sand bottom, the taxonomic identification is based on the morphological characteristics of larvae, even if it is very hard to show interspecific differences among gnathiids. For this reason, the morphological study was performed also by SEM to better show the surface details with taxonomic meaning. One to five mm long pranizae had a flattened body characterised by a head followed by 5 thoracic and 6 abdominal segments and a caudal plate with two biarticulated uropods. In the oral part of the head there was a ventrally oriented and smooth trapezoidal rostrum. Oral appendages, not clearly visible by light microscopy, were: a) two jaws with denticulate internal sides longer than the rostrum; b) a single ipostoma apically divided into two long appendixes; c) long and thin maxillae, with denticulate distal margins; d) two paired maxillipedes showing ciliate internal side that reaches the extremity of buccal cone; e) two big gnatopods with apical nail. Flagellum of antennulae had 7 articles. Telson was triangularly shaped, longer than large, with truncated apex having two apical bristles. Uropods were short with rounded internal angle and were provided by smooth and plumose setae; endopod was larger than exopod. The jaw of the adult gnathiid male, studied only by light microscopy, was solid, with oblique and denticulated blade; long and thin apex; rounded internal lobe; prominent external spur. Morphological characteristics of the jaw of the adult male and the shape of larvae permitted us to identify our specimens as Gnathia vorax (Lucas, 1850).

Unitubulotestis sardae (Trematoda: Didymozoidae) infection in Atlantic bonito Sarda sarda (Perciformes: Scomberomoridae) in the Ionian and Tyrrhenian Seas: histopathological and SEM investigations.

Nematobothrinae are trematoda digenea that usually live in cysts in fish tissues. They have been reported in different teleost species although the host-parasite relationships remain to be elucidated. This report is aimed at analysing the presence of Unitubulotestis sardae in the Atlantic bonito (Sarda sarda) populations fished in the Straits of Messina. The histopathological change reported in literature in similar cases is an aneurisma verminosa saccata, whereas, in the specimens here described, we show neovascularisation and at the same time, hyperplasia of the gill epithelium, leading to the formation of a bistratified cystic wall. The SEM examination of the parasitic cysts gave us a better understanding of the surface microanatomical details of the cystic walls. The external surface appeared to be constituted by a pluristratified covering epithelium of the gill arch. The internal layer was constituted by a net of blood vessels richly anastomosed with those originating from the gill arch arteries. This could be in agreement with data reported by Grabda (1947) on the localisation of the juvenile stages of the parasite in this blood vessel, but the evolution in cysts formation does not show similarities with the formation of an aneurisma.

Scanning electron microscopy of the carapace of some Mediterranean crab species.

Observation by SEM of the carapace microstructure of crabs showed, in the past, numerous differences at a specific level (i.e. in the genus Ebalia and Liocarcinus) as described by Spanò et al. (1995, 1999). The aim of this study is to describe the carapace micromorphology of some crab species of very different genera and species. A critical analysis of ecological data and morphological parameters is carried out in order to determine if the differences have adaptive significance.