1,720,970 research outputs found
IMPLEMENTATION OF THE HABITAT FISH BIO-INDICATOR IN TWO WATER BODIES OF THE VENICE LAGOON: THE ROLE OF SEASONAL AND ENVIRONMENTAL VARIABILITY IN THE ASSESSMENT OF ECOLOGICAL STATUS OF FISH FAUNA
Full text linkUnder the Water Framework Directive (WFD; Dir. 2000/60/EC), fish are one of the Biological Quality Elements that need to be taken into account when evaluating the Ecological Status of transitional water bodies. The Habitat Fish Bio-Indicator (HFBI), a multi-metric index composed of six descriptors based on functional traits of fish assemblages, was recently developed to assess Italian transitional waters. In this study, HFBI was applied, following the national application protocol, to two water bodies in the Venice lagoon featuring different water and sediment physco-chemical properties and habitat distribution. The analysis highlighted that, in addition to seasonality, environmental variability along confinement gradients and presence and extent of seagrass meadows strongly influence the six metrics, the HFBI score and the subsequent assessment outcome. The selection of number and location of sampling sites must then be based on environmental characteristic and variability found within each water body, and is therefore a crucial step in the evaluation of Ecological Status in transitional water ecosystems
Popolamenti microalgali in habitat a barene e loro contributo alla dieta del necton
No full textMicroalgae small-scale distribution was investigated to quantify their trophic role in the complexity of saltmarsh habitats. Sampling surveys were carried out in 2019 in the Venice lagoon (Italy), in three areas, inside the saltmarsh creek (ghebo) and outside. The nekton community was estimated by seine net and water and surface sediment samples were collected to determine microalgae taxonomic composition and biomass. Mean phythoplankton biomass increased from the more to the less confined areas and it was more abundant during summer and outside the ghebo. Microphytobenthos biomass, on the contrary, did non follow the confinement gradient and was more abudant in spring and inside the ghebo. Fish biomass had more density outside the ghebo. However, the juvenile belonging to the genus Chelon (30% of the nekton community biomass) was found to be more abundant inside the ghebo than outside and their stomachs contained numerous diatoms
Influence of Seascape on Coastal Lagoon Fisheries: the Role of Habitat Mosaic in the Venice Lagoon
Full text linkFisheries are a staple human activity supported by coastal lagoons. Together with water quality and trophic status, lagoon
morphology is acknowledged as one of the main ecological drivers of fishery yields; however, the role of lagoon seascape
structure is still poorly understood. This paper investigates how morphological variables, habitat distribution and seascape
diversity and complexity affect yields of artisanal fishery performed with fyke nets in the Venice Lagoon (northern Adriatic
Sea, Italy). Two spatial scales were considered in the analysis, with water quality parameters (temperature, salinity, dissolved
oxygen, turbidity, water residence times, N, P and chlorophyll-a concentrations) being measured at a fine, fyke-net scale and
morphological (average bottom elevation and sediment grain size) and habitat features (habitat proportion, diversity and
complexity) being measured at a broader, seascape scale. Generalised linear mixed models were employed to model 8 years
of nekton and green crab catches, disentangling the role of broad-scale morphology and seascape from that of fine-scale
water quality. Broad-scale variables clearly influenced fishery target species. Among them, lagoon residents were associated
with specific morphological and habitat characteristics, while marine migrants showed a stronger link with overall habitat
diversity and complexity. This evidence emphasises how artisanal fishery in the Venice Lagoon relies on the conservation
of morphological and habitat heterogeneity. Moreover, it highlights how habitat restoration performed at the seascape level
should also be taken into account, in addition to controlling hydrology and water quality, when managing fishery resources
in coastal lagoons
Predicting the response of nekton assemblages to seagrass transplantations in the Venice lagoon: An approach to assess ecological restoration
Full text link1. One of the major challenges to ensure effective restoration of estuarine habitats is to establish success criteria to determine whether the goals of restoration are met. 2. The aim of this work is to propose and test an approach to identify reference conditions and assess the recovery of nekton (fish, decapods and cephalopods) assemblages at seagrass restoration sites. 3. Nekton sampling took place from 2014 to 2017 in the northern Venice lagoon (northern Adriatic Sea, Italy) during spring at eight sites subjected to seagrass (Zostera marina and Zostera noltei) transplantation. In spring 2016, five natural seagrass sites in the same area were additionally sampled, and physico‐chemical water parameters and habitat structure were also recorded. 4. A multivariate generalized linear model approach was adopted in order to disentangle the relative effect of water quality and seagrass habitat structure on nekton assemblages of natural habitats. Models were subsequently employed to predict species composition of nekton fauna at each transplantation site, to identify the reference assemblage expected under site‐specific abiotic and habitat characteristics. 5. The average distance of the observed assemblage from reference conditions was used to track temporal trajectories of nekton colonization at transplantation sites, and to ultimately evaluate the recovery rate towards restoration goals. 6. This study highlights how a predictive approach could serve management purposes in ecological restoration, providing a concise tool to assess the functionality of restored habitats for associated fauna
FISH FAUNA IN THE VENICE LAGOON: UPDATING THE SPECIES LIST AND REVIEWING THE FUNCTIONAL CLASSIFICATION
Full text linkThis work aims at reviewing the existing ecological classification of fish fauna in the Venice lagoon, and updating the list of species found during 15+ years of research in this ecosystem. The checklist encompass all fish life stages including ichthyoplankton, and contains 94 taxa, with 14 recorded only after 2010. The new functional classification, made of eight guilds including two guilds of lagoon residents and two of marine migrants, highlights the differences
in species’ use of lagoon habitats in different seasons
Using fish assemblage to identify success criteria for seagrass habitat restoration
Full text linkA fish-based multimetric index was applied to assess the ecological status of fish fauna in both natural and newly restored seagrass meadows in the Venice lagoon (northern Adriatic Sea, Italy), using natural habitats as reference sites. Fish assemblages were then compared, and community attributes of recreated and natural habitats were evaluated. Ecological status resulted higher in natural meadows, and a multivariate analysis showed that an increase in the relative proportion of seagrass specialists at restored sites could represent an indicator of success of seagrass restoration
APPLICATION OF THE HABITAT FISH BIOLOGICAL INDEX (HFBI) FOR THE ASSESSMENT OF THE ECOLOGICAL STATUS OF PO DELTA LAGOONS (ITALY)
Full text linkFish fauna is one of the biological quality elements useful for assessing the ecological status of European transitional water bodies, for the purposes of applying the Water Framework Directive. For the assessment of the ecological status of Italian transitional aquatic ecosystems, the multimetric index “Habitat Fish Bio-Indicator” (HFBI), based on fish fauna, was developed and validated at national level. This paper reports the results of a study on the shallow-water fish fauna of 5 lagoon environments of the Po Delta (Northern Adriatic, Italy) which aimed to evaluate the ecological status of these water bodies by calculating the HFBI. The results made
it possible to describe the taxonomic composition and the functional and trophic structures of the fish community characteristic of these delta lagoons. The shallow water fish assemblage was characterized by the presence of juvenile stages of marine migrating species (i.e., grey mullets of the genus Chelon, the sea bream Sparus aurata and the sea bass Dicentrarchus labrax) and by species of estuarine residents (i.e., small gobies Knipowitschia panizzae, Pomatoschistus marmoratus, and P. canestrinii, the silverside Atherina boyeri and the killfish Aphanius fasciatus). The guilds of hyperbentivores/zooplanktivores, microbentivores and detritivores were the most represented in the fish assemblage of the of investigated lagoons. The HFBI index, applied on an annual basis, made it possible to highlight marked differences in the ecological status of the Po Delta lagoons. Only Caleri lagoon resulted in a good state, Marinetta and Canarin lagoons in a moderate state, while Barbamarco and Scardovari lagoons resulted in a poor ecological state. Eutrophication, resulting from the large inputs of nutrients with freshwater from the Po River branches, and the modification of lagoon morphologies, a consequence of anthropogenic activities, are the main pressure factors that determine the ecological status of these transitional water bodies
DISTRIBUTION OF THE ALIEN SPECIES PALAEMON MACRODACTYLUS RATHBUN, 1902 IN THE VENICE LAGOON
Full text linkPalaemon macrodactylus Rathbun (1902) is an estuarine shrimp native to north-western Pacific which, due to its wide environmental tolerance to chemical-physical conditions and its long breeding period, from 1957, probably carried by ship ballast water, massively colonized estuarine ecosystems worldwide. After its first record, in 2012, P. macrodactylus appears to have rapidly colonized the entire Venice lagoon, showing higher abundance in the confined saltmarsh stations of the northern sub-basin, probably due to the relatively low salinities values of this area. Records collected from 2014 to 2020 confirm the long reproductive period, comprised between Spring (mid-April) and Autumn (October), and the potential large invasion capacity of this species, which in the future could provoke competition with autochthonous species of the genus Palaemon and Crangon crangon
Importanza conservazionistica delle barene nel reclutamento dei giovanili di Mugilidi
No full textThe role of saltmarsh sub-habitats in favouring Mugilidae recruitment was investigated by measuring parameters that describe the trophic chain in three saltmarsh areas of the Venice lagoon from March to June 2019. Chelon ramada juveniles, the most abudant Mugilidae species in the present paper, were found to clearly prefer the creeks inside the saltmarsh, while C. aurata, C. saliens and C. labrosus were more abudant on the saltmarsh outer edges. Focusing on their diet preference, the microphytobenthos abundance was estimates and it was demonstrated the higher productivity of the creeks inside the saltmarsh compared to the open outer areas
- …
