1,720,965 research outputs found
Vulnerability of the Northern Adriatic Sea Fishery to Climate Change
No full textWithin the context of marine environments, nekton assemblages are recognised to provide several kinds of ecosystem services, both fundamental and demand–derived. They contribute, indeed, to enhance the biodiversity, the ecological processes and
finally the system resilience. They also directly support the production of goods, such as in the case of renewable resources exploited by commercial fisheries. The problem of the impacts of climate change on this component of marine ecosystems,
with the related consequences on ecosystem services, becomes therefore an interesting issue. In this context, the northern Adriatic Sea, hosting several species adapted to boreal climatic conditions, can be considered a good case study. By
analysing the composition of landings from fisheries in terms of thermal affinity groups, we highlighted the potential vulnerability of these activities. Catches, indeed, were shown to be mainly composed of cold and temperate affinity species, whereas
the contribution of warm ones resulted very low. Given the significant negative relationships between the cold and temperate groups with the recorded variations of the thermal regime and the latest projections by the IPCC in terms of ocean temperature raise, fishing activities, both professional and recreational, can be expected to experience severe consequences
Present and future status of artisanal fisheries in the Adriatic Sea (western Mediterranean Sea)
Full text linkArtisanal fisheries represents an important source of employment and income for many Mediterranean coastal communities, as well as an important cultural and traditional identity factor at a regional level. However, despite its importance, it is generally under-studied, in both ecological and socio-economic terms, so hampering the chance of developing sustainable and integrated management measures. At present, on the West coast of the Adriatic Sea, within the three-mile area, artisanal fisheries and hydraulic dredging are the only approved commercial fishing activities. This study confirmed the importance of the artisanal fisheries in this area, representing a multitarget and multigear activity. Despite the 39 exploited species, however, we found high vulnerability both for species (76% of total catches depend upon only three species-cuttlefish, mantis shrimp, and sole) and thermal affinity groups (cold and temperate species contributed to the entire catches). Furthermore, our data showed that fishing effort and CPUE values were greater than those reported at the regional level, and also indicated that the discard rate was lower than in other Adriatic areas. Regarding ecological effects, the two trophodynamic indicators that we applied showed a sustainable situation, but scenarios of possible changes in environmental or fishing effort conditions highlighted the proximity of the stock to the unsustainability threshold. Our findings suggest the need for an adequate management strategy to cope with possible future changes in population boundaries and conditions
Il contributo della modellistica alla gestione lagunare
No full textA dispetto degli elevati impatti antropici subiti, l’ecosistema lagunare Veneziano mostra ancora elevata resilienza, provvedendo a fornire un ampio range di servizi ecosistemici (Rova et al., 2015, 2019). Nel quadro dell’implementazione della Direttiva Quadro sulle Acque (Water Framework Directive 2000/60/EC, European Community, 2000), la laguna di Venezia è stata suddivisa in 14 unità operative, definite corpi idrici (ISPRA-ARPAV, 2018). Il percorso di implementazione della Direttiva è giunto al secondo ciclo di valutazione, nel quale si è considerata la qualità dei diversi corpi idrici, sulla base di singoli Elementi di Qualità Biologica (BQEs). La sfida attuale, che accomuna la laguna di Venezia a molti altri corpi idrici di transizione a livello EU, è quella di individuare misure adeguate volte a migliorare lo stato ecologico di un determinato corpo idrico (a riguardo vedi Anelli Monti et al., 2021). In questo contesto, il presente contributo si propone di descrivere i tratti principali di due assi di ricerca attualmente in corso, volti ad indagare come diversi contributi della modellistica ecologica possano concorrere all’individuazione di misure gestionali per il sistema lagunare. A ciascuno di questi ambiti viene qui di seguito dedicato uno breve paragrafo
Specie aliene termofile e funzionamento dell’ecosistema: il caso di studio dell’Alto Adriatico
No full textGlobal thresholds in properties emerging from cumulative curves of marine ecosystems
No full textThere are several emergent properties useful as indicators of marine ecosystem status. Some of these are based
on the cumulative trophic theory, which posits that biomass and production accumulate in repeatable and
predictable patterns across trophic levels. These patterns result in a suite of curve parameters that can delineate
when a marine ecosystem is undergoing perturbation or recovery. When looking at this suite of curve parameters,
and their trajectories over time, a clear sense of perturbation, recovery, or transition can be delineated.
From a set of over 3700 observations we established empirical threshold levels for the curve parameters, i.e.,
Trophic Level inflection point, Biomass inflection point and Steepness at 3.38 ± 0.05, 0.33 ± 0.01 and
0.50 ± 0.56, respectively. When the three parameters are examined collectively to determine whether a particular
ecosystem datum was below or above each of these three thresholds, clear three-dimensional patterns
emerged. First, some volumes in this 3-D space of parameters simply did not have data, and many volumes had
very little. The majority of data (approximately 40%) occurred in situations with Steepness and Biomass inflection
point higher than thresholds. Almost none of the ecosystems (< 1%) was below all three thresholds at
any point in time, a quarter of the data resulted in critical conditions for at least a couple of indicators, a little
less than half of the ecosystems (52%) at any point in time seem to be quite functional from this emergent
property perspective, and finally, a moderate number of ecosystems, at any point in time (22%), seem to be in
some type of transition state. We assert that these emergent properties have value for delineating ecosystem
state, and at the very least when the Biomass inflection point is<33% an ecosystem is understood to have been
severely degraded. Using these three thresholds, and identifying whether data trajectories are crossing them or
not, has strong potential to better indicate the status of marine ecosystems, trajectories thereof, and hence when
management interventions are needed
Inside and outside the boundaries: contribution of the valli da pesca to the Venice lagoon Ecosystem Services
No full textThe Venice lagoon is a social-ecological system, result of centuries of co-evolution between natural and anthropogenic drivers. All this produced a complex interacting set of different habitats and parts, including
some confined, man-managed areas known as valli da pesca. These areas, similar to ‘miniature lagoons’, have progressively been separated in a permanent way from the lagoon itself, depending almost completely on human intervention for functioning and maintenance. Due to both the “artificial” origin and
difficulties of accessing, these portions of the lagoon have previously been excluded from analyses, surveys, monitoring programs. The present work constitutes the first attempt of a spatially explicit Ecosystem Services (ESs) assessment of the entire lagoon, included the valli da pesca, both in terms of capacity and flow. Obtained results showed that these areas, despite they represent just the 18% of the total lagoon area, play an important ecological role, contributing for 35% of the ESs capacity and 27% of the flow in comparison with the whole lagoon. Furthermore, the valli da pesca showed that different management strategies, aimed to maximize just a single ES, like aquaculture or hunting (or both), could have significant contrasting effects on the landscape features
Vulnerabilità della pesca in Alto Adriatico in relazione ai possibili effetti dei cambiamenti climatici
No full textThe Influence of Fishers’ Behavior on Recreational Fishing Dynamics and Catch: Insights from a Mediterranean Coastal Lagoon
No full textRecreational fishing is practiced by thousands of people in European coastal waters and is steadily gaining popularity. Serving multiple purposes, recreational fishing provides fresh fish for meals, offers leisure, and contributes to traditional ecological knowledge, especially at the local level. Therefore, analyzing its dynamics and catch is a complex task, since they not only depend on the environmental features but also on the behavior of fishers. In coastal areas, however, most recreational fishers remain unmonitored, making it difficult to obtain data on their impact on fish stocks. This is particularly evident in the Venice lagoon, where we conducted a comprehensive study aiming to characterize recreational fishing dynamics. We collected data through interviews, online questionnaires, and remote sensing techniques, including satellite imagery photointerpretation and machine learning algorithms. Our findings reveal spatial and temporal variations in fishing activity, with certain areas and times experiencing higher fishing pressure. This highlights a seasonality in fishing activity and a pattern in fishers’ behaviors that are associated with fish migratory dynamics. Such an association demonstrates the local fishers’ understanding of the fish lifecycle phases and the environmental conditions of the lagoon. Regarding the catch, the most targeted species are seabream (Sparus aurata), seabass (Dicentrarchus labrax), and cuttlefish (Sepia officinalis), with estimated total catches of 18.65 t per year, 15.82 t per year, and 8.36 t per year, respectively. However, our results showed a significant disproportion between the biomass caught by two different groups of fishers that differ in terms of fishing trip frequency, success rate, and catch. While the average catch of the first group, representing most recreational fishers, might be considered of low impact, the catch of the second group, encompassing recreational fishers who fish with very high frequency and efficiency, is substantial in the context of the lagoon ecosystem. Indeed, even considering a conservative estimate, recreational fishing in the Venice lagoon accounted for approximately 2% of the catch of cuttlefish and 17% of the catch of seabream compared to commercial fishing catch, whereas the catch of seabass by recreational fishing approached that of commercial fishing. Therefore, the implementation of a periodic monitoring program utilizing methods such as machine learning algorithms and remote sensing technologies could support the management of recreational fishing dynamics. We also suggest that participatory processes involving both professional and recreational fishers may aid in defining shared approaches and bottom–up initiatives, ensuring enjoyment as well as sustainable uses of coastal areas
The Influence of the Spatial Scale on the Fishery Landings-SST Relationship
Full text linkPossible effects of the spatial scale of analysis on the relationship between fishery landings and the water temperature in the Mediterranean Sea have been investigated using the FAO capture database (1970-2010). The analysis was performed by dividing species in three thermal affinity categories: cold, temperate and hot species. Results showed significant changes in fishery landings composition during the last four decades, in terms of the relative contribution of cold, temperate and hot species to landings; moreover, the presence of a strong influence of water warming in determining the landings temporal pattern has been confirmed. This relationship, however, resulted to be not homogenous across the tested spatial scales (entire Mediterranean basin, three main sub-basins, eight FAO areas). The best models (based on the Akaike Information Criterion), were the ones fitted at the finer spatial definition (i.e. the eight FAO areas) for all the three thermal affinity categories. The recorded relationship showed clear differences in terms of direction, depending on both areas and thermal affinity groups. Cold species showed a negative relationship with the increasing water temperature in all the FAO areas, being partially replaced by temperate ones, with the exception of the Adriatic and Black Sea (the coldest areas in the Mediterranean basin), where a moderate increase in the water temperature is still favoring the cold affinity group. This kind of results could be useful within the context of the management plans definition, within a context of climate changes
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