70 research outputs found
Fish response to multiple anthropogenic stressors in mediterranean coastal lagoons: A comparative study of the role of different management strategies
Transitional waters are among the most productive ecosystems of the world and their biotic communities show high diversity and complex mechanisms of self-regulation that provide valuable ecosystem services and societal goods and benefits. In this work a comparison of the fish assemblages of three non-tidal Mediterranean coastal lagoons is carried out in order to evaluate the impacts of alternative management strategies. The anthropogenic pressures acting on the lagoons were quantified by means of categorical indicators, while the characteristics of the fish assemblages were summarized in multi-metric indices (MMIs). Two MMIs were developed using data collected with a beach seine net and with fyke nets, following an empirical approach that selects, from a pool of 73 metrics, the combination that maximizes the MMI/pressure relationship. The two MMIs include four metrics each, most of which are based on feeding mode functional guilds and habitat use functional guilds, and they are sensitive to anthropogenic pressures. The human activities directly or indirectly affecting water quality are the ones that most influence the fish assemblage, while the presence of artisanal fisheries, a typical and relevant resource use in these lagoons, seems to play a beneficial role. Lagoon fisheries management relies on the maintenance of infrastructures that guarantee the hydraulic functioning of the lagoon, thus ensuring exchanges with the adjacent coastal sea, and therefore indirectly contributing to the habitat quality
Growth of Wild Gilthead Seabream (Sparus aurata L.) Juveniles for Organic Aquaculture
The majority of organic marine fish farms currently begin the production cycle with non-organic juveniles from conventional hatcheries, permitted by the European Regulation on organic fish origin (EC 710/2009) until the end of 2016. Wild juvenile gilthead seabream (Sparus aurata) from coastal lagoons and hatcheries were experimentally reared under organic conditions, in order (1) to investigate differences in fillet lipid content and fatty acids composition, and (2) to propose a possible future source of juveniles destined for organic aquaculture. Wild juveniles were readily distinguishable by their fatty acid signature, showing significantly higher ratio levels of n-3 polyunsaturated fatty acids and n-3/n-6. Fillet lipid composition of organically fed wild S. aurata juveniles was preferable to that from domesticated juveniles. These results seem promising for organic aquaculture, where fish feed is more environmentally sustainable but is of lower nutritional qualit
Skin pigmentation in gilthead seabream (Sparus aurata l.) fed conventional and novel protein sources in diets deprived of fish meal
The pattern of yellowish pigmentation of the skin was assessed in gilthead seabream (Sparus aurata) fed for 12 weeks iso-proteic (45%) and iso-lipidic (20%) diets deprived of fish meal and containing either a blend of vegetable protein-rich ingredients or where graded levels of the vegetable protein blend were replaced by insect (Hermetia illucens\u201410%, 20% or 40%) pupae meal, poultry by-product meal (20%, 30% or 40%), red swamp crayfish meal (10%) and marine microalgae (Tisochrysis lutea and Tetraselmis suecica\u201410%) dried biomass. Digital images of fish fed diets differing in protein sources were analyzed by means of an automatic and non-invasive image analysis tool, in order to determine the number of yellow pixels and their dispersion on the frontal and lateral sides of the fish. The relationship between the total carotenoid concentration in the diet and the number of yellow pixels was investigated. Test diets differently affected gilthead seabream skin pigmentation both in the forefront and the operculum, due to their carotenoid content. The highest yellow pixels\u2019 number was observed with the diet containing microalgae. Fish fed poultry by-product meal were characterized by the lowest yellow pixels\u2019 number, diets containing insect meal had an intermediate coloring capacity. The vegetable control, the microalgae mix diet and the crayfish diet had significantly higher values of yellow pixels at both inspected skin sites
Whole Genome Sequencing Provides Information on the Genomic Architecture and Diversity of Cultivated Gilthead Seabream (Sparus aurata) Broodstock Nuclei
The gilthead seabream (Sparus aurata) is a species of relevance for the Mediterranean aquaculture industry. Despite the advancement of genetic tools for the species, breeding programs still do not often include genomics. In this study, we designed a genomic strategy to identify signatures of selection and genomic regions of high differentiation among populations of farmed fish stocks. A comparative DNA pooling sequencing approach was applied to identify signatures of selection in gilthead seabream from the same hatchery and from different nuclei that had not been subjected to genetic selection. Identified genomic regions were further investigated to detect SNPs with predicted high impact. The analyses underlined major genomic differences in the proportion of fixed alleles among the investigated nuclei. Some of these differences highlighted genomic regions, including genes involved in general metabolism and development already detected in QTL for growth, size, skeletal deformity, and adaptation to variation of oxygen levels in other teleosts. The obtained results pointed out the need to control the genetic effect of breeding programs in this species to avoid the reduction of genetic variability within populations and the increase in inbreeding level that, in turn, might lead to an increased frequency of alleles with deleterious effects
No apparent genetic bottleneck in the demographically declining European eel using molecular genetics and forward-time simulations
No apparent genetic bottleneck in the demographically declining
European eel using molecular genetics and forward-time
simulations
Evaluation of environmental quality of mediterranean coastal lagoons using persistent organic pollutants and metals in thick-lipped grey mullet
The evaluation of past and present anthropogenic impacts affecting the ecological quality status of transitional ecosystems is crucial from the perspective of protecting them from further deterioration, and to evaluate remediation and restoration measures. Contamination patterns of thick-lipped grey mullet from two Mediterranean coastal lagoons within a protected area in Italy were assessed and compared in order to evaluate their overall quality status and to collect information that can provide useful feedback on management choices aimed at enhancing environmental quality and biodiversity conservation. The quality status of the two lagoons was evaluated by an environmental assessment methodology based on indicators of direct and indirect human pressures, while a broad range of analyses were carried out to determine the presence and concentration of persistent organic pollutants (POPs) and metals in fish muscle tissue. A good quality status resulted for both lagoons, and an overall limited anthropogenic impact in the surrounding area. This could account for POPs and metal contamination levels found in mullet, although limited, and relating to their patterns. The overlap of results achieved with the two evaluation approaches can provide support for management choices in Mediterranean lagoon environments, especially for those committed to the protection and conservation of biodiversity
Sviluppo di strumenti tecnologici predittivi sanitario/meteo-ambientali per potenziare lâefficienza e la sostenibilitĂ degli impianti di molluschicoltura: avvio del progetto FORESHELL
FORESHELL project is funded by the FLAG Costa Blu trough 2014-20 EMFF program of the Abruzzo Region. It is carrying out a pilot initiative to develop sanitary/weather-environmental predictive technological tools to enhance the efficiency and sustainability of the mussel farm in the Giulianova Maritime District. The hydrographic basins of the rivers close to the farm, Vibrata and Salinello, are constantly monitored trough the hydrological model (CHyM), to forecast occurrences of discharge peaks at the river mouth. Moreover, a specific sampling programme is established before and after severe weather events to determine the concentration of E. coli in freshwater at the river mouths and in mussels/seawater at the farming area. Until September 2021, there were 4 meteorological events that did not cause a peak discharge at the river mouth. Results did not show a significant increase of E. coli in the mussels. At the same time, the environmental parameters such as sea water temperature, salinity, chlorophyll a, sea currents and wave motion are acquired by the satellites and in situ probe. The web application for data visualisation is under construction, as well as the early warning signalling to the farmer. Furthermore, the growth of mussels is constantly monitored with biometric controls. In conclusion, the implementation of all phases of the FORESHELL project are progressing according to the timeline in order to develop innovative tools useful for the management of mussel farming area
Otolith shape variation provides a marker of stock origin for north Atlantic bluefin tuna (Thunnus thynnus)
Eel (Anguilla anguilla L. 1758) population structure in the low course of the river Tiber (Latium, central Italy), and preliminary considerations on its contribution to escapement
European eel (Anguilla anguilla l., 1758) demographic structure was studied in the low course of the river Tiber (Latium, Italy), where a professional fishery targeted to eel has been operating for more than 30 years, with the aim to evaluate its present state in relation to a general decrease of the local stock. this reduction is revealed by the catch contraction following the reduced glass eel recruitment to this river, consistent with what is observed at the continental level.
Monthly samplings were carried out from may to november 2006. A total of 454 specimen of Anguilla anguilla were examined in order to assess the developmental stage (on the basis of body colour: yellow eel, silver eel and intermediate), total length, weight and morphometric measures (pectoral fin length, vertical and horizontal eye diameter). A subsample of 229 specimen was sacrificed in order to collect otholits for age evaluation, gonads for sex determination, swimbladders for evaluation of nematode Anguillicola crassus infestation. the developmental classification has been tested by a supervised regression technique, the partial least squares analysis (pls). In order to estimate the Tiber eel population growth curve, age-at-length has been back-calculated by using a linear model regression of the total length on the caudal radius of the otholits. Theoretical growth has been calculated by von bertalanffyâs model.
On the whole, eel population structure in the Tiber does not show great changes with respect to previous investigations, contrary to what expected in relation to a possible decrease in population density. The low recruitment level might still be sufficient to sustain eel density and population structure in the low course of the tiber, because fishing effort on juveniles has ceased in the meantime. Some preliminary considerations can be made in relation to the contribution of the tiber eel stock to overall escapemen
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