Bathymetric and longitudinal distribution analyysis of the rockfish Helicolenus Dactylopterus (Delaroche, 1809) in the southern Tyrrhenian Sea (central Mediterranean)

This study provides information on bathymetric and longitudinal distribution heterogeneity of the rockfish Helicolenus dactylopterus in the southern Tyrrhenian Sea. Data were drawn from experimental bottom trawl (1996-2002) plus bottom trap (2001-02) surveys. The frequency of occurrence and mean relative density (N/km2) and biomass (kg/km2) indexes were calculated for two survey seasons (spring and autumn), four geographic sectors and three depth strata. MANOVA was used to test fish abundance among years, sectors and strata. Analysis of the length-frequency distributions was carried out by two-way (gears and depths) ANOVA, post hoc multiple comparisons for testing differences among depths and Student’s t test for testing differences between gears. Length-weight relationship was also estimated and the allometric coefficient was tested with the Student’s t test. The results showed a significant positive bathymetric gradient of sizes both for trawl and trap surveys; at same depths, fish caught by traps were significantly longer than those caught by trawl. In spring surveys, significant differences were found among strata for both abundance indexes; in autumn surveys, significant differences between depth strata were found only for density indices. The distribution and abundance patterns of H. dactylopterus along the southern Tyrrhenian Sea was homogeneous among sectors. Length-weight relationship showed a significant positive allometric growth

Vincitore del Premio ‘Sapienza Ricerca’, 16 Novembre 2011.

We develop a 800km long relative baseline of metal pollution for the Tyrrhenian Sea, from the north of Naples to south of Sicily (Italy), based on spatio-temporal (1997–2004) concentrations of trace metals in marine organisms and on the bioaccumulative properties of those organisms. The study concerns sites in the gulf of Gaeta-Formia, near Naples, and three islands north, west, and south of Sicily: Ustica, Favignana and Linosa. The five metals are: cadmium, chromium, copper, lead, and zinc; the species include: Monodonta turbinata (n = 161), Patella caerulea (n = 244) and the algae Padina pavonica (n = 84). We use Johnson’s (1949) [15] probabilistic method to determine the type of distribution that accounts for our data. It is a system of frequency curves that represents the transformation of the standard normal curves. We find an N–S pollution gradient in molluscs considered: the lowest metal pollution occurs around the Sicilian islands. Our method can accurately characterize marine pollution by contributing to: policy-making, coastal resources management, the assessments of environmental damages from marine accidents and other events. The method here presented is a useful tool for pollution comparisons purposes among ecosystems (i.e., risk monitoring) and it is an ideal starting point for its application on a global scale

Reproduction in the dusky grouper (Epinephelus marginatus, Lowe 1834) from South Mediterranean.

Demographic data and gonad histology confirmed that the dusky grouper Epinephelus marginatus is a protogynous hermaphrodite that follows a monandric pathway to sexual development. Females reached first sexual maturity at 36\u20227 cm LS and estimated mean length at first maturity (L50) was 43\u20228 cm LS for females and 81\u20223 cm LS for males. Adult sex ratios during the reproductive period were c. 3\u20225 : 1 females to males. Females exhibited group synchronous ovarian development and multiple ovulation occurred over the spawning period. Gonads were ripe from early May and spawning occurred from June until early September. The size of ripe testes (0\u20226% W) indicated strong oligospermy and suggested a mating system with no sperm competition. Sexual transition was protogynous involving regression of ovarian tissue and proliferation of testicular tissue in the gonads. Transitional individuals occurred from May through November and accounted for 9% of sampled adult population. Sex change occurred in fish 69\u201393 cm (LS) long and the size distributions of males and females overlapped over 27% of the LS range. Special zones were recognized as gathering areas for sexually mature dusky groupers during the reproductive period

Sexual maturity of wild red porgy females (Pagrus pagrus).

Pagrus pagrus is a protogynous teleost occurring in the Mediterranean sea and found as far as the Eastern and Western Atlantic coasts. The references about the reproductive biology of the porgy in the literature are related to wild populations of the Atlantic area and Mediterranean sea The spawning period last throughout the winter months and up to the beginning of spring in the eastern Atlantic area. Aim of this study was to describe gonad morphology, maturity stages and maturity size in wild females Mediterranean sea red porgy. Spawning period was identified throughout temporal frequency distribution of maturity stages during 3 year surveys

Changes in serum cortisol, metabolites, osmotic pressure and electrolytes in response to different blood sampling procedures in cultured sea bass (Dicentrarchus labrax).

This study investigated the e\u20acect of \uaeve sampling procedures on serum cortisol, glucose, total protein, osmolality, Na+, Cl\ub1, K+ and Ca++ concentrations in 2-year-old cultured sea bass (Dicentrarchus labrax L). Mild disturbance caused by rapid removal of fish and brief handling did not induce signi\uaecant variation in any of the blood parameters investigated. Confinement and crowding elicited a high and signi\uaecant increase in serum cortisol, glucose, osmolality, Na+, Cl\ub1 , and Ca++ concentrations. Exposure to MS 222 (140 mg L\ub11) significantly increased osmolality, but not ionic concentration. Site of blood withdrawal (cardiac sinuses/caudal vein) had no effect on the concentration of analysed blood constituents, except for K+ levels. Scattered literature of sea bass blood chemistry is reviewed and compared with `normal' ranges of blood constituents measured in this study. We conclude that it is necessary to select and rigorously execute an opportune blood sampling procedure whenever blood constituents are used as indicators of fish functional state

Effects of an acute stress challenge on physiological stress response of the sea bass Dicentrarchus labrax (L.) at different stocking densities.

Farmed fish are exposed to different stressing factors and their adaptive response depends both on the intensity and the duration of the stress. Understanding the nature of the physiological stress response and of its measurable consequences has a great importance in improving fish welfare and farm production. High stocking density is considered as an important source of stress in intensive aquaculture as it affects metabolic levels and modulates immune functions. Three duplicated groups of sea bass (mean initial body weight 151.4\uf0b133.5 g) were reared under closed circulated water system conditions at different stocking densities (7, 14 and 21 kg/m3) for 45 days. An acute stress challenge was performed on day 35 in order to investigate the physiological response of sea bass to an additional acute stressor. Fish were crowded for 15 minutes by maintaining them in shallow water inside the tank. Blood samples were drawn from the caudal vein (n=10 for each group) at different sampling times (before crowding, 30 minutes and 6, 24, 48, 72 hours after stress). Final sampling was performed at day 10. Serum cortisol and metabolite levels (glucose, total proteins, cholesterol, triglycerides and total non-esterified fatty acids) were measured. High stocking densities did not influence the physiological status of fish at the endocrine and metabolic levels. No significant variations in serum cortisol and metabolite levels were observed before the stress challenge. Acute stress challenge elicited a significant increase in cortisol, glucose, and non-esterified fatty acids levels in all groups, regardless of stocking density. No change in either serum triglycerides and cholesterol levels was detected. However, a significant quantitative difference in stress response was found among the different groups: fish kept at higher stocking densities showed a greater primary stress response, although recovery occurred within 24-48 hours post stress as in fish at medium and low stocking densities. This study demonstrated that sea bass kept at a high stocking density were more sensitive to an additional acute stressor. Exposure of fish to repetitive and cumulative stressing factors can affect their physiological status and their stress adaptive capacity. Therefore fish welfare should be improved by means of the control of stocking density and husbandry practices

On the use of optical remote sensing to assess phytoplankton biomass dynamics in the Pelagos Sanctuary (Ligurian-Provençal Sea)

If Marine Protected Areas (MPAs) are to aid in protecting and conserving marine ecosystems in the face of extensive and severe impacts of human activities, underpinning scientific knowledge and understanding of MPAs are imperative. This study aims to describe and evaluate phytoplankton dynamics in a pelagic Mediterranean MPA (The Pelagos International Marine Mammals Sanctuary) in the north-western Mediterranean Sea as a means to understand better the spatial and temporal distribution of basal ecosystem resources. Ocean colour data collected by orbital remote sensing (Sea-viewing Wide Field-of-view Sensor [SeaWiFS] data) were analysed to elucidate spatial and temporal variations in the concentration of chlorophyll-like pigments (chl). Mean chl images were generated for consecutive 10-day periods, to provide quasi-continuous coverage of the study area, combined with a Principal Component Analysis and analysis of a time series ​(1998–2004). The chl surface patterns traced seasonal upwelling events recurring annually, demonstrating the critical role of physical oceanography in sustaining the food web of the PelagosSanctuary. Phytoplankton blooms, however, differ in terms of peak timing, spatial distribution and chl concentration, due in part to the influence of broad-scale environmental factors that are beyond direct and regional control. Further research is needed to elucidate the relationship between the biomass of primary and secondary producers to understand better the implications of phytoplankton biomass distribution in space and time for charismatic and protected biota such as cetaceans

Soil chemical features as key predictors of plant community occurrence in a Mediterranean coastal ecosystem

Modelling the relationships between soil chemical factors and vegetation in coastal areas provides a significant contribution to understanding the ecology and conservation of these ecosystems in the Mediterranean basin. The present study relates coastal plant communities and soil chemistry using multivariate analysis and generalized additive models (GAMs) in order (a) to determine the relationships between soil factors and plant community occurrence along a coastline-lagoon gradient; (b) to build best models of soil chemical predictors for coastal plant community occurrence. Distance from coastline was the primary driver of changes in plant community composition and soil factors on the Mediterranean coast. Field capacity, pH, CaCO3, NaCl and soil organic matter were the major parameters related to the pattern of vegetation distribution. Along the costaline-lagoon gradient, however, plant community and soil changes agreed for two main sequences of habitats. The first was in the sand dune environment, involving plant communities, the species composition of which varied in response to increasing soil development. The second was near lagoons, where vegetation responded to soil salinity, acting independently of other soil factors. Coastal plant community occurrence was explained by GAMs, using a few soil chemical predictors: pH and CaCO3 were the main predictors for dune communities but only partly explained their occurrence, whereas NaCl was the key factor for salt marsh community occurrence and largely contributed to the model. The results suggest that soil chemical changes can be detected through vegetation distribution, particularly in saline habitats. Thus, habitat-based models could be a useful tool to identify the key factors for different types of vegetation occurrence in coastal habitats

Development of an innovative marine monitoring system for CO(2) leaks: system design and testing

A critical component of long term geological sequestration of anthropogenic CO(2) will be our ability to adequately monitor a chosen site to ensure public and environmental safety. Near surface monitoring is particularly important, as it is possible to conduct sensitive and direct measurements at the boundary between the subsurface and the biosphere (i.e. surface water or atmosphere). While discontinuous surface monitoring is often performed, continuous monitoring is preferable if one hopes to observe a leak in its early stages to allow for rapid remedial action. The geochemical signal that may result from a near-surface CO(2) leak might take the form of increased soil gas concentrations (on land) or changing pH, Eh, and aqueous chemistry (in groundwater or surface water), and thus continuous monitoring stations capable of analyzing for these parameters have great potential for early leak detection. In the framework of the EC-funded CO2GeoNet and CO2ReMoVe projects innovative monitoring systems have been designed and constructed for autonomous deployment in marine environments above geological CO(2) storage sites. The system developed within CO(2)GeoNet was tested at a site in the Gulf of Trieste where there is no gas release; this site was chosen due to easy access and the presence of an existing oceanographic buoy onto which the monitoring station was mounted. Tests on this early prototype highlighted the various difficulties of working in marine environments, and this experience formed the basis for a new system developed for deployment at the Panarea test site within CO2ReMoVe. This second site is located off the coast of Panarea Island, to the north of Sicily, where naturally-produced CO(2) leaks from the seabed into the water column. The advantage of this site is that the leaks occur in a relatively near-shore environment (<300m) and in water that is not too deep (<25m), thereby allowing for easy access by SCUBA divers for system testing and maintenance. This location allowed the unit to be connected via cable, rather than a buoy, which makes power supply and data transfer simpler. The system developed for this site consists of three monitoring points that are connected to a land-based control unit. Each point, located 100, 200, and 300m from shore in different CO(2) flux regimes, is able to measure dissolved CO(2) and CH(4), conductivity, pH, and temperature using low cost but sensitive sensors. The complete system consists of flexible solar panels, a central control unit and three monitoring points, and data download is conducted using a GPRS connection and a web server. Difficulties with the initial deployment in early April of 2008 has necessitated further development work, with the second deployment planned for early November. The following paper discussed the experience gained with these stations, and presents data analysis and anomaly recognition from a land-based monitoring station that has been collecting dissolved CO(2) data for over 18 months. (C) 2009 Elsevier Ltd. All rights reserve