132 research outputs found
Evaluation of the Effects of the Enriched-Organic Diets Composition on European Sea Bass Welfare through a Multi-Parametric Approach
No full textThree groups of European sea bass (Dicentrarchus labrax) were fed for seven months, with either a conventional diet or two different organic diets, which contain organic vegetables and a natural antioxidant compound. The two organic diets differed themselves in terms of raw proteins, fish oil, and lipid contents. Sea bass welfare condition was assessed in relation to these three diets, using 16 different indicators. These were: swimming activity (recovery test, muscle activity), haematological and serological stress indicators (haematocrit, haemoglobin, red-blood-cell count, cortisol, glucose, lactate), aspecific immunity parameter (lysozyme), indicators of exposure to organic contaminants (7-ethoxyresorufin-O-deethylase and glutathione-S-transferase), and growth parameters (weight gain, specific growth rate, feed conversion ratio, protein efficiency ratio, and hepato-somatic index). Most of these parameters individually did not give consistent responses, but their integration can provide an accurate evaluation of the fish welfare conditions among the three diet experimental groups. The multiparametric approach outlined a comprehensive picture of sea bass physiological state. The principal component analysis and the multi-criteria-decision-analysis were found to be useful tools for an integrated fish welfare assessment, highlighting that the best welfare condition was achieved in the experimental group fed with the protein-rich organic diet
EFFECTS OF THE ENRICHED-ORGANIC DIETS COMPOSITION ON EUROPEAN SEA BASS (Dicentrarchus labrax) NEW TOOLS FOR FISH WELFARE EVALUATION IN AQUACULTURE
No full textIn recent years, concern for the welfare of animals, including fish, has a strong impact on public opinion, putting pressure not only on producers and the scientific community, but also on institution to guarantee adequate "standards” for animal welfare. The market today challenges the production capacity of aquaculture by asking for products with consistently high quality. Unlike other farming methods, there is a lack of scientific information on the welfare of fish reared under intensive aquaculture conditions. Among the various aspects that characterize aquaculture, the increase in fish welfare has an impact on public opinion also for economic reasons whereby is very important to keep animals in good health, determine a higher feed conversion rate, lower mortality, optimal growth rate and high quality of the animal raised. Whereas stress events, acute and chronic, are reflected on the flesh, due to the increase in muscle activity (generally associated with this condition). We have firstly demonstrated that accelerometer tags are useful tools for welfare monitoring, indeed they do not affect welfare and health of implanted fish and that tagged fish can be sampled during experiments and be considered as representative of population, by displaying similar growth and physiological parameters compared to untagged fish. Consequently, the purpose of this study is to investigate the effect of two organic diets (contain organic vegetables and a natural antioxidant compound) on the welfare of the European sea bass compared to one conventional. A holistic approach was adopted, including the measurement of the primary stress response (cortisol), secondary (i.e. lactate, glucose, haematological parameters, lysozyme) and tertiary (i.e. swimming performance, muscle activity and growth parameters) indicators. In parallel, we evaluated the enzymatic activities of 7-ethoxyresoruphine-O-deethylase and glutathione-S-transferase, as index of function of the microsomal hepatic system of mixed function oxygenase (MFO), to evaluate the possible effects of pollutant contamination through the diet. In this study, multiparameter analysis approaches were performed to bring a better understanding of the effectiveness of a holistic approach to quantify welfare in organic aquaculture. The multi-parameter approach has outlined a complete picture of the physiological state of the sea bass. The Principal Component Analysis and the Multi-Criteria-Decision-Analysis have proved to be useful tools for an integrated assessment of the well-being of the fish, highlighting that the best condition was achieved in the experimental group fed with the organic protein-rich diet
Age validation of the European Anchovy (Engraulis encrasicolus Linnaeus, 1758) in the Central-Southern Tyrrhenian Sea (West Mediterranean Sea)
No full textThe validation of growth of the European Anchovy (Engraulis encrasicolus Linnaeus, 1758) presents several gaps in the Mediterranean Sea, despite its growth has been widely studied using different methods. The uncertainty in estimating the European Anchovy age by otolith interpretation is linked to (i) the identification of the first growth ring; (ii) the presence of false increments; (iii) discrepancies in the applied age scheme (e.g. theoretical birthdate); and (iv) the progressive compactness of the last annuli in older specimens. The present study was conducted on specimens caught in Central-southern Tyrrhenian Sea between 2012 and 2016. The analyses of the otolith edge type and the marginal increment analysis allowed to describe the annuli deposition pattern, with the opaque ring deposited from June to September, and the translucent ring from October to May. The growth pattern inferred from the European Anchovy otoliths was either corroborated or indirectly validated by the agreement between the length–frequency results and the otolith age estimation. No significant differences were found between the von Bertalanffy growth curves calculated by otolith interpretation (back-calculation and direct otolith reading) and the LFDA. These outcomes resulted highly relevant for species, such as small pelagic fish, for which the direct validation methods (e.g. mark-recapture, captivity, radiochemical) are particularly difficult to implement
Relative benthic status guides sustainable trawl management in the Adriatic–Ionian Seas
No full textFishing activities with mobile bottom-contacting gears can heavily impact the seafloor, disrupting marine life and potentially leading to a loss of biodiversity. The impact of fishing pressure on benthic habitats depends on their natural sensitivity, the type of fishing gear, and the frequency and intensity of fishing. This study focused on assessing the health of benthic habitats in the Adriatic and Western Ionian Seas (Mediterranean Geographical Sub-Areas 17, 18, and 19), using the relative benthic status indicator, which quantifies the interaction between fishing pressure and habitat sensitivity. Results obtained provide relevant insights to help balance conservation goals with the need for sustainable fishery activities. The results revealed differences between the two studied areas. The Adriatic Sea, with its high concentration of fishing activity in muddy continental shelf habitats, showed significant degradation of the benthic state. In contrast, the Western Ionian Sea, characterized by a higher proportion of deeper waters, appeared to be in better condition due to comparatively lower fishing intensity. These findings highlight the critical need for spatially targeted management to mitigate the fishing impact. Two management scenarios were explored to support sustainable fisheries. The first scenario focused on introducing spatial closures in areas of ecological importance, reallocating banned fishing activities to less sensitive areas. The second scenario implemented a gradual reduction in fishing effort over five years, aligning with the regional management plan in force in the study area. While spatial closures resulted in localized improvements in benthic health, broader effort reductions offered more widespread benefits across the region. These findings underscore the importance of spatial planning and adaptive fishery management to protect marine habitats and their long-term productivity and diversity
A holistic approach to the age validation of Mullus barbatus L., 1758 in the Southern Adriatic Sea (Central Mediterranean)
No full textThe growth of Mullus barbatus has been widely studied using different methods, but no previous study has focused on age validation. The uncertainty in estimating the age of the red mullet by otolith reading is linked to the number of false-growth increments laid down before the annulus. The capture of red mullets in the early life stage allowed us to estimate their size at the metamorphosis from the pelagic to the demersal phase. The comparison between the metamorphosis size and the back-calculated length of the first growth increment clarified the position of the false growth increment on the otolith. Moreover, the analyses of the otolith marginal increments in adult and juvenile specimens allowed us to define the deposition patterns of their annuli. The modal components of the length–frequency distribution analysis (LFDA) were identified in the winter survey (ELEFAN and Bhattacharya methods), and they did not show significant differences from the length back-calculation of the annuli. Moreover, no significant differences were found between the growth curves calculated by otolith reading (back-calculation and direct otolith reading) and the LFDA. The agreement between the length–frequency results and the otolith age estimation either corroborated or indirectly validated the growth pattern estimated in the otoliths of the red mullet, mainly when the direct validation methods (e.g. mark-recapture, captivity, radiochemical) were difficult to implement, like the case of this species. The comparison of the results of the present work to previous Mediterranean studies showed agreement with the slow growth pattern
Age and growth of bamboo coral Isidella elongata (Esper, 1788): a Mediterranean Vulnerable Marine Ecosystem indicator taxa
No full textThe General Fisheries Commission for the Mediterranean of the Food and Agriculture Organization of the United Nations (FAO) recognises bamboo coral forests as Vulnerable Marine Ecosystems due to their high ecological importance (e.g., habitat-forming, shelter-role, and hot-spot biodiversity). The major cause of bamboo coral vulnerability lies in their slow growth rate, which limits their ability to recover from fisheries-related damage. This is particularly true for the bamboo coral Isidella elongata in the Mediterranean Sea. Despite the need to take action to ensure the conservation of the I. elongata forests, crucial information regarding life-history traits such as age, growth rate, and life span is still limited. This study takes advantage of the incidental catch of 751 I. elongata colonies (basal diameter 0.36–7.3 mm) through experimental trawl fishing surveys (2012–2023) in South Adriatic Sea. We modelled the species’ growth through thin sections (basal diameter < 2 mm) and radiocarbon dating (basal diameter > 4 mm). The estimated ages, considering both methods, ranged between 1 and 59 years, while the species’ lifespan in the area was predicted to be from 57.5 to 59 years. Age data were fitted to seven different growth models, with the exponential model proving to be the most accurate in describing the species’ growth with significant difference between two groups of age data (< 12 and > 48.8 years). Our findings are the first providing direct ageing of I. elongata in the Mediterranean Sea, which is a critical aspect in determining the species’ long-term population dynamics and recovery capacity from an ecosystem-based fishery management perspective
Movement patterns analysis as a tool in Fully Protected Areas design: Influence of relocations on travelled distances of Palinurus elephas (Fabr. 1787) in Sardinian FPAs (central-western Mediterranean)
No full textEffectiveness of restocking programs in Marine Fully Protected Areas' (FPAs) can be highly affected by the movement behavior of the species to protect. We analyzed the data of 744 Palinurus elephas specimens tagged, relocated inside 12 FPAs, established in the seas surrounding Sardinia (central-western Mediterranean), and then recaptured. The overall aims were to characterize the individuals' movements after the relocation and to discuss strengths and weaknesses of the current FPAs' design. Almost 80% of tagged individuals travelled progressively increasing distances, as a function of the release distance, up to a maximum value of 11,500 m. Then, for larger release distances, individuals' mobility appeared reduced and more chaotic. A similar trend was found analyzing the distances travelled with respect to the FPAs with the highest number of recaptured individuals and to the size. These results allow to establish a threshold limit of the release distance, to take into account when designing FPAs, as a useful tool to keep a portion of the individuals into FPAs’ borders, in order to both preserve the species and guarantee a spillover of individuals in the commercial areas
Spatial and temporal patterns in the mediterranean populations of aristaeomorpha foliacea and aristeus antennatus (Crustacea: Decapoda: Aristeidae) based on the MEDITS surveys
No full textThe aristeids Aristaeomorpha foliacea and Aristeus antennatus are two species of great economic importance in the Mediterranean Sea, where they are exploited almost exclusively by bottom trawlers. We analysed their geographical and inter-annual patterns using data collected, following a standardized protocol, during the MEDITS international experimental bottom trawl surveys. The data used consisted of standardized abundance and biomass indices, size structure and individual biological information collected in the northern Mediterranean for more than two decades. Several univariate and multivariate methodologies were used to analyse the data. The current study confirms previous findings, such as the longitudinal gradient in the relative presence of the aristeids, but also offers additional information for a better understanding of the intrinsic variability of the data over the years and between areas. Moreover, geographical variability in the somatic condition index is discussed, taking into account the role of environmental conditions and fishing pressure. The large geographical variability found for both species in this regional approach reflects the importance of additional studies at a small-scale geographical level. Such studies could be particularly important for managing and ensuring the stability of these species, for which large regional approaches may be inadequate
Control of hepatitis A by universal vaccination of children and adolescents: an achieved goal or a deferred appointment?
No full textTemporal trends of Hepatitis A cases and vaccination coverage data against Hepatitis A Virus have been investigated to analyse the impact of the universal routine vaccination strategy more than 10 years from its introduction in Puglia (region of Southern Italy). The basic reproductive number (R(0)) before vaccination introduction and the effective reproductive number (Re) after introduction have been calculated. A progressive decrease in incidence has been recorded in Puglia during last 10 years. Vaccination coverage is actually 64.8% (95% CI: 52.7-76.9%) for children aged 12-24 months and of 67.6% (95% CI: 58.4-76.8%) for 12-year-old adolescents. R(0) estimated in 1996 was 2.01; actually R(e) is 0.651. Theoretical age at infection is 31.82 years. Universal routine vaccination aimed at the control of direct transmission remains the milestone in the strategy for the containment of the disease in settings at an intermediate level of endemicity
Exploring a deep-sea vulnerable marine ecosystem: Isidella elongata (Esper, 1788) species assemblages in the Western and Central Mediterranean
No full textThe bamboo coral Isidella elongata is a key structuring species on deep muddy bottoms, which has suffered severe consequences from bottom-fishing activities, as it often co-occurs with precious fishery resources such as red shrimps. A five-year series of data collected during a scientific trawl survey was used to localize the presence and to characterize the associated megafauna over a wide spatial scale in the Western and Central Mediterranean (Sardinia, South-Central Tyrrhenian, Western Ionian and Southern Adriatic). In addition, the overlap of I. elongata hotspots with nursery and spawning areas of three selected species (Aristaeomorpha foliacea, Aristeus antennatus and Galeus melastomus) was analysed. The sizes of the colonies were analysed in the South-Central Tyrrhenian and the Southern Adriatic. No significant variation over time was observed in the former, while in the latter, the colonies were bigger but showed a decreasing trend over time
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