The European eel is a highly migratory fish. After the reproduction in the Sargasso Sea early larval-stages start a passive ocean migration towards European and Mediterranean continental waters. After several years as yellow eels, mature adults change to silver stage and then start their return trip. The trajectory of their backward migration is unknown, because of low probability of capturing migrating individuals, having this capture never been reported in the Mediterranean. Recently, 8 silver eels were collected in the Strait of Sicily. Using literature information about possible individual route and speed, their geographical position was projected up to the spawning site during reproductive season. Despite using optimal and continuous migration swimming speed, none of the specimens may have been able to reach the Sargasso Sea in time for mating. Subsequently, to identify putative Mediterranean areas from which eels could have been reaching the spawning grounds on time, a backward scenario was postulated using the previous scientific assumptions. Our results suggests that just a small quota of Mediterranean silver males successfully reaches the Sargasso area, and only females from the westernmost and central parts of the basin could be able to fruitfully pond their eggs during the supposed spawning period.

The spatial representation of decapod crustaceans (Crustacea, Malacostraca) of the Strait of Sicily (Central Mediterranean Sea) is presented for the first time, together with comments on their vertical and horizontal distributions. The most relevant trawlable species were analysed using quantitative data gathered in 260 daylight lasting hauls, which covered a large portion (about 100 000 km2) of the investigated area. The index of local abundance, standardized to 1 km2, both in weight (Biomass Index), number (Density Index) and mean body weight were obtained for each species and for all species combined. A spatial representation of the Density Index was produced for all decapod crustaceans combined and for the most frequent species. In particular, the indices were transferred under a GIS system and spatial maps produced by applying the program ArcView(TM) 9.0. Different interpolators were tested and the most exact interpolator (IDW Inverse Distance Weighting) was chosen. Both historical (i.e., doubts about the presence or identification of the species) and spatial (i.e., differential distribution among different fishing areas) heterogeneity were detected and commented upon. Concerning the trawlable bottoms, very few species (such as Parapenaeus longirostris (Lucas, 1846), Aristaeomorpha foliacea (Risso, 1827), Aristeus antennatus (Risso, 1816), Nephrops norvegicus (Linnaeus, 1758) and Plesionika martia (A. Milne-Edwards, 1883)) are consistently and largely represented in the catches. A high spatial heterogeneity, likely reflecting the complex interaction between fishing pattern, hydrological features and bottom typology, was made evident. © Koninklijke Brill NV, Leiden, The Netherlands.

Fishing with demersal towed gears can have dramatic effects on the structure and functioning of marine ecosystems. We studied the ecosystem effects of the deep-sea red shrimp Aristaeomorpha foliacea trawl fishery (500 to 800 m) in the Strait of Sicily, at the population and community level by sampling in trawled and non-trawled sites as determined by vessel monitoring system (VMS) fishing effort data. The study was conducted within the Maltese 25 nautical mile Fisheries Management Zone as part of the ongoing MEDITS trawl survey. Samples were collected using an experimental otter trawl net with a cod-end stretched mesh size of 20 mm, from 7 stations located in trawled sites (mean depth 616 +/- 26 m) and from 7 stations in non-trawled sites (mean depth 556 +/- 40 m). Population and community indicators were compared across the trawled and non-trawled sites. Populations of A. foliacea and Etmopterus spinax did not show any differences in biomass between the trawled and non-trawled sites, whereas the biomass of Plesionika martia, Nephrops norvegicus, Helicolenus dactylopterus dactylopterus and Galeus melastomus was 4 times, 16 times, 6 times and 2 times higher, respectively, at the non-trawled sites. Changes in length structure were also detected for all species except for E. spinax. At the community level, higher biomass, density and diversity indices were recorded at the non-trawled sites. Despite the clear evidence of ecosystem changes due to fishing, the main target species, A. foliacea and P. martia, had a high resilience to trawling activities. Setting up trawling lanes as a management option would likely minimise negative impacts on species with slow growth rates and low resilience.

Background. The African armoured searobin, Peristedion cataphractum, is a medium sized, gregarious, demersal fish distributed in the Eastern Atlantic and the Mediterranean Sea. Once considered abundant in all the Mediterranean basins, nowadays the species represents an appreciable by-catch of bottom trawlers only in limited areas. The aim of the present was to perform a synthetic analysis of the distribution, abundance, and biological traits of this poorly investigated species. Materials andMethods. This paper is based on the information recovered from the available "grey" data sources as well as on new original data gathered in 13 experimental bottom trawl surveys carried out off the southern coasts of Sicily from 1994 to 2005. Data recovering and processing regarded distribution, abundance, sex ratio, maturity condition, length structure, and its evolution in time, and growth estimation. Results. The specimens of P. cataphractum were present in all investigated areas, with highest abundance in the eastern grounds, between 50 and 800 m, showing a preference for the upper slope (201-500 m). Sexed specimens were almost equally distributed between females and males (overall sex ratio, Sr, between 0.49 and 0.54). Recruits (80-130 mm total length, TL) occurred continuously from September to March, with a peak from late December thru March. The size at onset of sexual maturity (L m at 50%) was achieved at 191 and 212 mm for females and males, respectively. Growth was evaluated (sex combined) by applying length based methods (LBMs); up five significant modal components were evidenced, the first 2-3 well distinguished. Two sets of the special von Bertalanffy function were derived reflecting juveniles/adult (L ? = 380 mm, Ky -1 = 0.34 and t 0y = -0.76) and adults (L ? = 313 mm, Ky -1 = 0.28 and t 0y = -0.99) growth trajectories. Conclusion. The review performed in the frames of the presently reported study helped to propose a plausible life history of the investigated stock.

In order to establish "historical" benchmark values, length based methods were used for an analysis of growth and mortality of the large scaled gurnard, Lepidotrigla cavillone (Lacepède, 1801), in the Strait of Sicily (Mediterranean Sea), using data collected in 1986 87. Implementing the Bhattacharya's method, 4 modal groups were identified in the LFDs, regardless of the season; fitting the modes was tried thru various different approaches, settling at the end for a classical von Bertalanffy growth function (vBGF), with L?= 163.8 mm, koy 1= 0.318, and t0= 1.48 y; optimum length (Lopt= 85 mm), total (Zoy 1= 1.48) and natural (Moy 1= 0.87) annual mortality were also derived. Incidentally, the growth-mortality pattern and the Lm Lopt-LFD comparison indicate a moderate exploitation for L. cavillone in the Strait of Sicily during the investigated period.

The deep water rose shrimp, Parapenaeus longirostris (Lucas, 1846), is one of the most valuable and heavily exploited demersal species of the Mediterranean bottom trawl fisheries. The basic life traits of this shrimp, in particular its reproductive aspects, are regularly monitored during experimental trawl surveys carried out in the Mediterranean Sea. Gonadic condition and maturity status for estimating the size at onset of sexual maturity are commonly assessed in females using macroscopic color scales, histologically validated only in a few geographical areas. In this study, histological analyses were performed on rose shrimps collected from a trawl survey carried out in the Strait of Sicily, in order to support the empirical 4 stage macroscopic scale locally employed. Ovaries from females of different sizes, ranging between 16 mm and 40 mm carapace length, were collected and used for microscopic examination of their structure, for oocytes counts and for oocyte diameter frequency distributions; oocytes diameter was measured by imaging analysis. The collected data were also used to estimate other basic vital parameters of the rose shrimp population. The histological observations show a broad correspondence between ovarian development and macroscopic features; therefore, the classifications derived by the empirical scale remain suitable for estimating the maturity parameters.

This edited volume is a compilation of contributions from an American Fisheries Society symposium held in 2007. It features recent research into the evolution and ecology of diadromous fishes and describes the threats facing these species in a dynamic geophysical, biological, and sociopolitical environment. This is a timely publication given that many diadromous fish species around theworld are in steep decline due to habitat alteration, harvesting, pollution, hydropower development, and global climate change.

The Italian coastlines are sometimes shaped homogeneously, without references for short-range recreational boating. A multipurpose floating structure, based on the technology of the submersible cages for offshore aquaculture, might satisfy the man's search for peculiar spatial conformations to where orient themselves and "settle" their activities. Such artificial "atoll" should become an attracting magnet for small boats, a rod-fishing facility (like a "fishing pond"), an open-sea swimming pool, a resting spot and a catering station, the starting base for scuba diving, an educational and research tool. The module is made of 4 submersible net cages (to be sunk to avoid storms and for in loco winter storage); a pontoon, also submersible, serves as supporting space. A preliminary study suggests that the enterprise is economically viable even with a reduced exploitation season; moreover, the modular design may permit to easily expand the structure and to adapt the initiative to other suitable sites.

Lipofuscin, a not degradable degenerative fluorescent pigment which accumulates in post mitotic cells, represents a promising method for ageing marine crustaceans. The presence and accumulation of lipofuscin has been studied in the deep water red shrimp Aristaeomorpha foliacea (Risso, 1827), to assess its use as a tool for ageing larger (i.e., older) specimens and thus improve knowledge on growth and longevity of this species. Specimens, gathered during experimental trawl surveys carried out in the Strait of Sicily (Mediterranean Sea), were stored directly on board in 10% buffered formaldehyde solution; their brain was thereafter removed, prepared with various current histological techniques and examined with a binocular microscope. Thin sections of the olfactory lobe cell mass were also analyzed using fluorescence microscopy, and the lipofuscin concentration was measured thru image analysis. Various indexes were computed for each individual by pooling data from many images: number and coverage of the lipofuscin granules per unit area, and mean individual area of the granules. Lipofuscin was detected in all specimens investigated with characteristics (grain typology and dimension) strictly resembling those already described in other crustacean species. The present preliminary results are encouraging further studies to develop and validate a methodology based on the use of lipofuscin for improving the relative ageing of large A. foliacea shrimps.