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

Application of biotic and taxonomic distinctness indices in assessing the Ecological Quality Status of two coastal lakes: Caprolace and Fogliano lakes (Central Italy)

Marine biotic indices (AMBI, BENTIX) and the statistical tool M-AMBI (Multivariate AMBI) were applied as a comparative approach in assessing the Ecological Quality Status (EcoQS) of two Mediterranean coastal lakes (Caprolace and Fogliano lakes) situated in the Circeo National Park (Central Italy). The macrobenthic community was analysed using univariate indices (community structure), correspondence analysis (CA) and taxonomic distinctness indices (Delta(+) and Lambda(+)). The community composition showed a dominance of lagoonal species in both coastal lakes, while in Caprolace lake marine taxa were also found. Diversity index (H') complies to ranges found in Mediterranean lagoons and taxonomic distinctness indices demonstrated that taxonomy structure is in accordance with natural variability ranges. Principal component analysis (PCA) on chemical parameters of water and sediment showed that both coastal lakes differ mainly in their organic matter composition. In fact, the protein fraction of bio-polymeric carbon prevails in Fogliano lake, while the 'refractory' component represented by carbohydrate fraction is predominant in Caprolace lake. The difference between the two coastal lakes was also demonstrated by co-inertia analysis (COIA) performed using abundance of species and concentrations of chemical parameters. The results from the application of the three biotic indices do not highlight a clear distinction between the two lagoons. However, the AMBI index provided a more suitable evaluation of EcoQS corresponding to 'slightly polluted' lagoons while M-AMBI and moreover BENTIX indices indicated a worsening situation. The biotic indices are widely used in assessing the EcoQS in marine environments, but their proper application in transitional waters would depend on a resettlement; thresholds established in the biotic index scale values need to be modified according to natural variability of transitional waters referring to abiotic conditions and abundance of tolerant species. (C) 2008 Elsevier Ltd. All rights reserved

Crustacean fishery with bottom traps in an area of the southern Tyrrhenian Sea: species composition, abundance and biomass

The north-eastern coast of Sicily is characterized by deep, steep bottoms, not easily exploitable by trawl fishery. In this area few fishermen use bottom traps to catch shrimps and Norway lobsters. Our studies were aimed at identifying the species' composition, abundance and biomass of crustaceans exploitable by bottom traps in this area. Monthly samples over one year were obtained from two lines of 30 baited traps each, at depths between 100 and 500 m. One line was placed in an area usually exploited by this fishery; the other line was used in the unexploited deepest bottoms. Trapped specimens were counted and weighed. ANOVA test, post hoc multiple comparisons and Student's t test were applied on abundance and biomass data, for testing differences between areas, among seasons and species. During 22 fishing days, 23 species characteristic of the bathyal mud assemblage were caught, 8 of which were not considered commercial. Plesionika edwardsii was the most important species, recorded in the whole bathymetric range investigated; Nephrops norvegicus was significantly higher in terms of biomass in the unexploited area. The discard, of slight importance, was mostly represented by the crab Liocarcinus depurator. Spring season yielded the best catches in both areas, showing the highest values for both abundance and biomas

Reduced emergent character of neural dynamics in patients with a disrupted connectome

High-level brain functions are widely believed to emerge from the orchestrated activity of multiple neural systems. However, lacking a formal definition and practical quantification of emergence for experimental data, neuroscientists have been unable to empirically test this long-standing conjecture. Here we investigate this fundamental question by leveraging a recently proposed framework known as “Integrated Information Decomposition,” which establishes a principled information-theoretic approach to operationalise and quantify emergence in dynamical systems — including the human brain. By analysing functional MRI data, our results show that the emergent and hierarchical character of neural dynamics is significantly diminished in chronically unresponsive patients suffering from severe brain injury. At a functional level, we demonstrate that emergence capacity is positively correlated with the extent of hierarchical organisation in brain activity. Furthermore, by combining computational approaches from network control theory and whole-brain biophysical modelling, we show that the reduced capacity for emergent and hierarchical dynamics in severely brain-injured patients can be mechanistically explained by disruptions in the patients’ structural connectome. Overall, our results suggest that chronic unresponsiveness resulting from severe brain injury may be related to structural impairment of the fundamental neural infrastructures required for brain dynamics to support emergence

Whole-brain modelling identifies distinct but convergent paths to unconsciousness in anaesthesia and disorders of consciousness

The human brain entertains rich spatiotemporal dynamics, which are drastically reconfigured when consciousness is lost due to anaesthesia or disorders of consciousness (DOC). Here, we sought to identify the neurobiological mechanisms that explain how transient pharmacological intervention and chronic neuroanatomical injury can lead to common reconfigurations of neural activity. We developed and systematically perturbed a neurobiologically realistic model of whole-brain haemodynamic signals. By incorporating PET data about the cortical distribution of GABA receptors, our computational model reveals a key role of spatially-specific local inhibition for reproducing the functional MRI activity observed during anaesthesia with the GABA-ergic agent propofol. Additionally, incorporating diffusion MRI data obtained from DOC patients reveals that the dynamics that characterise loss of consciousness can also emerge from randomised neuroanatomical connectivity. Our results generalise between anaesthesia and DOC datasets, demonstrating how increased inhibition and connectome perturbation represent distinct neurobiological paths towards the characteristic activity of the unconscious brain

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

Perceptual load affects exogenous spatial orienting while working memory load does not.

We examined whether or not increasing visual perceptual load or visual working memory (WM) load would affect the exogenous orienting of visuo-spatial attention, in order to assess whether or not exogenous orienting is genuinely automatic. In Experiment 1, we manipulated visual perceptual load by means of a central morphing shape that in some trials morphed into a particular target shape (a rectangle) that participants had to detect. In Experiment 2, the possibility that the presentation of any changing stimulus at fixation would eliminate exogenous orienting was ruled out, by presenting two alternating letters at fixation. In Experiment 3, we manipulated visual WM load by means of arrays consisting of three (low-load) or five (high-load) randomly located coloured squares. The participants had to remember these items in order to judge whether a cued square had been presented in the same or different colour at the end of each trial. In all the experiments, exogenous visuo-spatial attentional orienting was measured by means of an orthogonal spatial cuing task, in which the participants had to discriminate the elevation (up vs. down) of a visual target previously cued by a spatially nonpredictive visual cue. The results showed that increasing the perceptual load of the task eliminated the exogenous orienting of visuo-spatial attention. By contrast, increasing the WM load had no effect on spatial orienting. These results are discussed in terms of the light that they shed on claims regarding the automaticity of visuo-spatial exogenous orienting

Physiological responses of European sea bass Dicentrarchus labrax to different stocking densities and acute stress challenge

Stocking density is considered a priority topic in aquaculture research due to its bearing on the welfare of farmed fish and the need for future recommendations governing stocking density management on fish farms. In this study, two consecutive experiments were carried out in order to investigate the physiological response of sea bass Dicentrarchus labrax to different stocking densities and to an acute stress challenge. Three duplicate groups of sea bass (mean BW= 139.8 g; TL = 18.6 cm) were reared in six recirculating tanks (5 m(3)) at three stocking densities (15, 30 and 45 kg/m(3)) for 6 weeks, and then crowded at 100 kg/m(3) for 15 min. Sampling was performed after 2 weeks and at the end of the stocking density experiment (6 weeks) and at 1, 6, 24, 48, 72 h and 10 days after crowding. Blood samples were analyzed for cortisol, glucose, non-esterified fatty acids (NEFA), total proteins, triglycerides and cholesterol concentrations. Univariate and multivariate analyses were applied to the data sets. No differences in growth and survival were observed in sea bass kept at 15, 30 and 45 kg/m(3) for 6 weeks. Serum cortisol levels measured at 2 and 6 weeks were not significantly different among density groups. A significant increase in NEFA concentration was observed in sea bass kept at 45 kg/m(3) after 6 weeks, suggesting enhanced lipid mobilization. In response to an additional acute crowding stressor, the levels of cortisol and NEFA were significantly higher and of glucose significantly lower in sea bass reared at 45 kg/m(3) compared to fish kept at 15 and 30 kg/m(3). However, pre-stress levels were recovered after 24-48 h in all groups. Multivariate analysis did not reveal any discrimmant variables among groups, indicating similar physiological conditions in the sea bass experiencing different stocking densities and similar recovery patterns after crowding. Results indicate that stocking density at 45 kg /m(3) for 6 weeks did affect the energetic status of sea bass and their sensitivity to a subsequent crowding stressor. Taking into account that aquaculture practices usually involve multiple stressors, a proper recovery time from stress is recommended to enable sea bass to preserve their physiological status

Reproduction of dusky grouper (Epinephelus marginatus, Lowe, 1834) in the wild and under controlled conditions.

Sexual and reproductive patterns of wild Epinephelus marginatus were carefully investigated by means of histological and histochemical analysis, sex steroid profile and demography data. Acquired knowledge was utilized to manage broodstock in captivity. A male broodstock was developed through hormonal sex inversion of juveniles. In captive females, ovarian maturation and ovulation were induced by substained GnRHa treatments. Artificial fertilization trials, embryonic development and first larval rearing trials were described

Stress response and innate immunity in sea bass Dicentrarchus labrax subjected to acute and chronic crowding stress.

This study investigates the stress and innate immune responses of sea bass Dicentrarchus labrax experiencing different stocking densities and subjected to a subsequent acute stress challenge. Three duplicated groups of sea bass were reared at 15, 30 and 45 kg/m3 for 5 weeks, and then were over-crowded up to 100 kg/m3 for 15 min. Primary and secondary stress indicators (plasma cortisol, glucose, non-esterified fatty acids, cholesterol, triglycerides, total proteins) and innate immune parameters (complement, lysozyme, burst respiratory activity of leucocytes) were measured before stress (days 0, 7 and 35) and following crowding stress (1, 6, 24, 48, 72 hours and 10 days). Rearing density up to 45 kg/m3 did not evoke a chronic cortisol response, although induced a significant mobilization of energy substrates. Higher stocking density significantly affected serum complement and burst respiratory activities of leucocytes, whereas serum lysozyme levels were unchanged. Acute stress challenge induced a typical stress response in all groups, producing a significant but transient variation of cortisol and metabolite levels. Recovery occurred 24 hrs post-stress although fish held at a higher stocking density showed a more elevated acute response. A significant decrease of both complement activity and lysozyme concentration were observed 6 hrs post-stress and recovery of pre-stress levels occurred within 10 days. These results suggest that a rearing density higher than 30 kg/m3 over a period of 5 weeks significantly affects the innate immune response of sea bass and increases the magnitude of the stress response following an acute stress challenge