Sergio Vitale

Abundances of demersal sharks and chimaera from 1994-2009 scientific surveys in the central Mediterranean Sea.

Bibliographic and data gathered in scientific bottom trawl surveys carried out off the Southern Coasts of Sicily (Mediterranean Sea), from 1994 to 2009 and between a depth of 10 and 800 m, were analysed in order to prepare a checklist of demersal sharks and chimaera, which are species sensitive to fisheries exploitation. Out of the 27 previously reported demersal shark and chimaera taxa in the Mediterranean, only 23 were found in literature and 20 sampled during the surveys in the investigated area. Among the species sampled in the surveys, only 2 ubiquitous ( Squalus blainville and Scyliorhinus canicula ) and 3 deep-water ( Chimaera monstrosa , Centrophorus granulosus and Galeus melastomus ) species showed a wide geographical distribution with a consistent abundance. Excluding the rare (such as Oxynotus centrina ) or uncommon shark (e.g. Squalus acanthias ), the estimated frequencies of occurrence and abundance indexes show a possible risk of local extinction for the almost exclusively (e.g. angelshark, Squatina spp.) or preferential (e.g. Scyliorhinus stellaris ) neritic species.

Growth Parameters and Population Structure of Aristeus Antennatus (Decapoda, Penaeidae) in the South Tyrrhenian Sea (Southern Coast of Italy)

The blue and red shrimp Aristeus antennatus (Risso, 1816) is one of the most important fishery resources in the Mediterranean Sea. Monthly samplings of blue and red shrimp from June 2006 to May 2007 were landed by the trawl fleet in two northwest Sicilian fishing harbours (San Vito Lo Capo and Terrasini). The carapace length (CL) frequency distribution of females ranged between 15.00 and 59.00 mm, whereas male CLs ranged between 17.00 and 34.00 mm. The estimated parameters of the Von Bertalanffy growth function (VBGF) for San Vito lo Capo females and males were: CL∞ = 65 mm, K = 0.58 y–1 and CL∞ = 41 mm, K = 0.71 y–1, respectively; while for Terrasini females and males these were: CL∞ = 69 mm, K = 0.65 y–1 and CL∞ = 37 mm, K = 0.8 y–1, respectively. In this study, we update the information on stock structure and growth parameters of the blue and red shrimp in two northwest Sicilian fishing grounds and compare these results with other data recorded in the Mediterranean Basin.

Old Info for a New Fisheries Policy: Discard Ratios and Lengths at Discarding in EU Mediterranean Bottom Trawl Fisheries

Discarding is considered globally among the most important issues for fisheries management. The recent reform of the Common Fisheries Policy establishes a landing obligation for the species which are subject to catch limits and, in the Mediterranean, for species which are subject to Minimum Conservation Reference Size (MCRS) as defined in Annex III to Regulation (EC) No 1967/2006. Additionally, several other initiatives aim to reduce unwanted catches of target and bycatch species, including species of conservation concern. This raises the need to study discarding patterns of (mainly) these species. In this work we collated a considerable amount of historical published information on discard ratios and lengths at discarding for species caught in EU Mediterranean bottom trawl fisheries. The main aim was to summarize the available historical records and make them more accessible for scientific and managerial needs, as well as to try identifying patterns in discarding. We show discard ratios and lengths at which 50% of the individuals were discarded (L50) for 15 species (nine bony fishes, three crustacean decapods and three elasmobranchs). Discard ratios were usually low for target species such as hake, red mullets and highly commercial shrimps and exemptions from the landing obligation under the de minimis rules could be sought in several cases. Discard ratios were usually higher for commercial bycatch species. Discarding is affected by a combination of factors and for a given species, especially for non-target ones, discards are likely to fluctuate within a fishery, across seasons, years and regions. For most species considered, L50s were lower than the MCRS (when in place) and length at first maturity. L50s of target species, such as hake, were very small due to the existence of market demands for small sized individuals. However, for species of low demand, like horse mackerels, a higher retention size was observed, often exceeding MCRS. Lengths at discarding are affected by legal provisions, market demands but also by biological, population and ecological traits. Understanding the factors that affect discarding constitutes the starting point for designing mitigation measures and management plans to reduce discards and improve the sustainability of the stocks.

Hazardous properties and toxicological update of mercury: From fish food to human health safety perspective

ABSTRACT The mercury (Hg) poisoning of Minamata Bay of Japan widely activated a global attention to Hg toxicity and its potential consequences to the aquatic ecosystem and human health. This has resulted to an increased need for a dynamic assembly, contextualization, and quantification of both the current state-of-the-art and approaches for understanding the cause-and-effect relationships of Hg exposure. Thus, the objective of this present review is to provide both hazardous toxic properties and toxicological update of Hg, focusing on how it ultimately affects the aquatic biota to potentially produce human health effects. Primarily, we discussed processes that relate to Hg exposure, including immunological aspects and risk assessment, vulnerability, toxicokinetics, and toxicodynamics, using edible fish, swordfish (Xiphias gladius), as a model. In addition, we summarized available information about Hg concentration limits set by different governmental agencies, as recognized by national and international standardization authorities.

Twenty-five-year longevity of European hake (Merluccius merluccius) from novel use of bomb radiocarbon dating in the Mediterranean Sea

The high variability of growth and longevity estimates for European hake (Merluccius merluccius) reflects the existence of two opposing hypotheses on growth rates that differ by a factor of 2: (1) a fast-growing hypothesis (FGH) with a maximum age near 15 years; and (2) a slow-growing hypothesis (SGH) with a maximum age near 30 years. A recently established regional radiocarbon (14C) reference led to a first-time application of bomb 14C dating in the Mediterranean Sea to three of the largest-sized and potentially oldest-catch female European hake. Because age reading of otoliths is very subjective and poorly defined, these fish were aged blind with bomb radiocarbon (14C) dating as an independent estimate of validated age. The validated ages were compared with the theoretical maximum ages from the most reliable FGH and SGH von Bertalanffy growth functions. Among the three bomb 14C ages, the most diagnostic length-at-age was an alignment with the bomb 14C rise period for two of the three fish, providing validated ages of 22 years (74.5-cm total length) and 25 years (88-cm total length). The results provide estimates of length-at-age that are in agreement with the SGH and cannot be accounted for by the FGH.

Lighting Methods Employed in Harvest of Fishery Products: A Narrative Review

Fishermen since time immemorial have employed various lighting methods aimed for favourable/successful harvest of fishery products. The latter on the other hand have evolved with habitat constituents for example, the waters, light and other external factors, which contribute to evolve the sensory adaptations. Whilst there is considerable literature about lighting approaches/methods employed in harvest of fishery products, no appraisal concerning the state-of-the-art to best of our knowledge has been performed. In this review, (some) relevant information about lighting methods employed in harvest of fishery products will be summarized under the following sub-headings: (a) Light as resource for fishing; (b) Eye of fish for vision and survival; (c) Catching the fish with light: experimental methods and instrumentation; (d) Light intensities that looks at: (i) attraction and reaction of fish; (ii) active escape of fish; (iii) induced stress of fish; as well as (e) Simulated trawls and conducted surveys. Some recommendations to direct future studies are also summarized.

Effects of different ozonized slurry‐ice treatments and superchilling storage (−1°C) on microbial spoilage of two important pelagic fish species

Abstract Combining different preservative treatments for improving quality and safety of fishery products increasingly receives global research attention. Consistent with this pursuit, the current research was undertaken to determine the effects of different ozonized slurry‐ice treatments and superchilling (−1°C) storage on microbial spoilage of European anchovy (Eugraulis encrasicolus) and sardine (Sardina pilchardus), which are two commercially important pelagic fish species. After the catch (within <5 hr) and at defined scheduled storage times, ozone has been discharged once on sardine (herein referred to as “One‐T”) and repeatedly/sequentially on European anchovy (herein referred to as “Seq‐T”). Microbiological analyses enumerated total viable count (TVC), Bacillus spp., Enterobacteriaceae, Lactobacillus spp., Moraxella spp., Shewanella spp., Listeria monocytogenes and Pseudomonas spp. Independent of potential antimicrobial effects of ozone during superchilling storage, no Listeria spp., Shewanella spp., Moraxella spp., and Bacillus spp. were found in all processed samples. While Enterobacteriaceae and Lactobacillus spp. were detected at below 1 log cfu/g, both TVC and Pseudomonas spp. proliferated at different rates throughout superchilling storage. The repeated ozone‐treated (“Seq‐T”) showed lower TVC and Pseudomonas spp. values compared with one‐time treated (“One‐T”) slurry‐iced and control samples. Thus, combined slurry‐ice and superchilling storage at Seq‐T produced improved antimicrobial activity over One‐T application. Largely, ozonized slurry‐ice outcomes/results appear promising thanks to superchilling storage.

On the Acclimatization of Pelagic Fish Species Juveniles in a Closed Environment: An Atlantic Horse Mackerel Case Study

Understanding how fish species acclimatize to a new environment may help to improve aquatic/fisheries resource management. Further, baseline information specific to behavior patterns of (pelagic) fish species juveniles particularly during acclimatization appears unreported to best of our knowledge. Therefore, the current study was goaled to examine the acclimatization of pelagic fish species juveniles in a closed environment using Trachurus trachurus as a case reference. Eighteen Trachurus fish juveniles were maintained in well-kept seawater-filled aquarium under laboratory/room conditions of controlled temperature. The characteristic observations of fish aggregation, fish-to-feed movement and fish-feed selection that varied across begin (days 1-5), middle (days 6-15) and end (days 16-20) phases provided substantiations about either how and when Trachurus spp. juveniles started, increased and or achieved complete/full acclimatization behavior. The initial peak (laboratory/room = ~18°C; water = ~20°C) temperatures of 20-day acclimatization period would stabilize with time. Along with the abovementioned characteristic observations, water temperatures seemed to fluctuate more compared to laboratory/room. Overall, the current study provides noteworthy baseline knowledge about pelagic fish juveniles’ behavior(s)/pattern(s) in closed environment and useful reference for future acclimatization studies.

Toward crustacean without chemicals: a descriptive analysis of consumer response using price comparisons

Background To date, there seems to be limited-to-zero emphasis about how consumers perceive crustacean products subject to either chemical and or non-chemical preservative treatments. In addition, studies that investigated price comparisons of crustacean products subject to either chemical or chemical-free preservative methods seem unreported. Objective This study focused on providing some foundational knowledge about how consumers perceive traditionally harvested crustaceans that are either chemical-treated and or free of chemicals, incorporating price comparisons using a descriptive approach. Design The study design employed a questionnaire approach via interview using a computer-assisted telephone system and sampled 1,540 participants across five key locations in Italy. To actualize consumer sensitivity, ‘price’ was the focus given its crucial role as a consumption barrier. Prior to this, variables such as demographic characteristics of participants, frequency of purchasing, quality attributes/factors that limit the consumption of crustaceans were equally considered. Results By price comparisons, consumers are likely to favor chemical-free (modified atmosphere packaging) crustacean products amid a price increase of up to 15%. But, a further price increase such as by 25% could markedly damage consumers’ feelings, which might lead to a considerable number opting out in favor of either chemical-treated or other seafood products. Comparing locations, the studied variables showed no statistical differences (p>0.05). On the contrary, the response weightings fluctuated across the studied categories. Both response weightings and coefficient of variation helped reveal more about how responses deviated per variable categories. Conclusions This study has revealed some foundational knowledge about how consumers perceive traditionally harvested crustaceans that were either chemical-treated or subject to chemical-free preservative up to price sensitivity using Italy as a reference case, which is applicable to other parts of the globe.

Evidence of trawling impact on Hoplostethus mediterraneus in the central–eastern Mediterranean Sea

The silver roughy, Hoplostethus mediterraneus is a benthopelagic cosmopolitan fish regularly caught as by-catch of the deep-water crustacean trawl fishery (CTF) in the central–eastern Mediterranean. Monthly samples of silver roughy were sampled from the catches of four commercial trawlers in 2004. Each trawler operated in different fishing grounds (FGs), located off Northern Tunisia, South of Sicily, Malta Islands and in South Levant, for which different exploitation levels are reported. The overall length–frequency distribution (LFD) was constructed, and fishing impact indices (length as percentage of LFD, optimum and maximum length, percentage of mega-spawners and total mortality/von Bertalanffy curvature ratio) were calculated. In spite of an overall acceptable status (juveniles, matures and mega-spawners were present in the catch), sampling data revealed significant differences in LFD shape and status indices between FGs. Those FGs traditionally considered more exploited (Northern Tunisia and South of Sicily) showed a dominance of juveniles, a rarefaction of mega-spawners, a reduction in maximum and asymptotic length and a higher Z/K ratio. Considering the general homogeneity of Mediterranean deep-water habitats, the pelagic dispersal of eggs and the poor swimming capabilities of silver roughy, the present results indicated that deep-water trawling may induce a slow and subtle, although significant, erosion of the older, late maturing and slow growing component of the stocks in the Mediterranean (so-called longevity-overfishing).