Dario Angeletti

Invertebrate welfare: an overlooked issue

While invertebrates make up the majority of animal species, their welfare is overlooked compared to the concern shown to vertebrates. This fact is highlighted by the near absence of regulations in animal research, with the exception of cephalopods in the European Union. This is often justified by assumptions that invertebrates do not experience pain and stress while lacking the capacity for higher order cognitive functions. Recent research suggests that invertebrates may be just as capable as vertebrates in experiencing pain and stress, and some species display comparable cognitive capacities. Another obstacle is the negative view of invertebrates by the public, which often regards them as pests with no individual personalities, gastronomic entities, or individuals for scientific experimentation without rules. Increasingly, studies have revealed that invertebrates possess individual profiles comparable to the personalities found in vertebrates. Given the large economic impact of invertebrates, developing certain attitude changes in invertebrate welfare may be beneficial for producers while providing higher welfare conditions for the animals. While the immense number and type of species makes it difficult to suggest that all invertebrates will benefit from increased welfare, in this review we provide evidence that the topic of invertebrate welfare should be revisited, more thoroughly investigated, and in cases where appropriate, formally instituted.

Terrestrial gastropods (Helix spp) as sentinels of primary DNA damage for biomonitoring purposes: A validation study

We validated the alkaline comet assay in two species of land snail (Helix aspersa and Helix vermiculata) to test their suitability as sentinels for primary DNA damage in polluted environments. The study was conducted under the framework of a biomonitoring program for a power station in Central Italy that had recently been converted from oil to coal‐fired plant. After optimizing test conditions, the comet assay was used to measure the % Tail DNA induced by in vitro exposure of hemocytes to different concentrations of a reactive oxygen species (H2O2). The treatment induced significant increases in this parameter with a concentration effect, indicating the effectiveness of the assay in snail hemocytes. After evaluating possible differences between the two species, we sampled them in three field sites at different distances from the power station, and in two reference sites assumed to have low or no levels of pollution. No species differences emerged. Percent Tail DNA values in snails from the sites near the power station were higher than those from control sites. An inverse correlation emerged between % Tail DNA and distance from the power station, suggesting that the primary DNA damage decreased as distance increased away from the pollution source. Detection of a gradient of heavy metal concentration in snail tissues suggests that these pollutants are a potential cause of the observed pattern. The comet assay appears to be a suitable assay and Helix spp. populations suitable sentinels to detect the genotoxic impact of pollutants. Environ. Mol. Mutagen. 54:204–212, 2013.

Seasonal characterisation of maritime traffic and the relationship with cetacean presence in the Western Mediterranean Sea

Seasonal maritime traffic was investigated in relation to cetaceans, through direct observations (July 2013-June 2015) along three fixed transects in Western Mediterranean. Visually obtained vessel abundance was compared with Automatic Identification System data to explore if the two methods provided different results. Traffic intensity and composition were characterised by seasons and vessel categories. Finally, cetacean presence was investigated in relation to traffic by measuring the difference of vessel abundance in the presence and absence of animal sightings. Results showed that visual sampling was consistent with AIS data, providing more information on small-medium vessels. Traffic was more intense and diverse in Spring/Summer, and the highest vessel abundance and seasonal variations in composition emerged for inshore subareas. The difference of traffic in the presence and absence of cetaceans was higher in most offshore subareas in Spring/Summer, verified for B. physalus and S. coeruleoalba; in inshore waters, mostly occupied by T. truncatus, no significant differences emerged.

Amount, composition, and spatial distribution of floating macro litter along fixed trans-border transects in the Mediterranean basin

Marine litter is a major source of pollution in the Mediterranean basin, but despite legislative requirements, scant information is available for the ongoing assessment of this threat. Using higher size classes as proxy for litter distribution, this study gave a synoptic estimation of the amount, composition, and distribution of floating macro-litter in the Mediterranean. The average amount of macro-litter was in a range of 2-5items/km2, with the highest in the Adriatic basin. Seasonal patterns were present in almost all study areas and were significant in the Ligurian Sea, Sardinian-Balearic basin, and Central Tyrrhenian Sea. Plastic accounted for >80% of litter in all areas and seasons, with the highest proportion in the Adriatic Sea, Ligurian Sea, and Sicilian-Sardinian Channels; in the Bonifacio Strait, Tyrrhenian Sea, and Sardinian-Balearic basin, litter composition was instead more diverse. Spatial analysis suggested an almost homogeneous distribution of litter without evident regular aggregation zones.

Habitat overlap between bottlenose dolphins and seabirds: a pilot study to identify high-presence coastal areas in the Tyrrhenian Sea

The identification of foraging hotspots able to support the co-existence of multiple top predators provides a potential approach to addressing protection measures for marine ecosystems. In this study, we conducted visual surveys in the central Tyrrhenian Sea to determine areas with simultaneous presence of bottlenose dolphins, four species of seabirds (Audouins gull, Yellow-legged gull, Yelkouan shearwater and Corys shearwater), and baitballs occurring at the surface, indicating the presence of potential prey items. We also analysed their occurrence in relation to topography (depth, slope and distance from the shore) and seabed types. Kriging analysis identified areas with simultaneous presence of several marine top predators. Dolphin distribution appeared to be linked to gentle slope (6–10 m) and muddy seabed, possibly associated with prey distribution, whereas the four seabird species were more frequent in areas with a water depth of 100–150 m, gentle slope and muddy seabed, apart from Audouins gull, which preferred a depth of 10–20 m. Baitball distribution was linked to depth (20–40 m), gentle slope (6–10 m) and muddy seabed. The overlapping presence of bottlenose dolphins, seabirds and baitballs allowed the identification of foraging areas, presumably representing biodiversity and productivity hotspots, located in waters of 50–100 m depth at the mouths of two rivers. This approach provides a promising tool for identifying highly productive coastal areas, and should also be recommended for wider-scale surveys.

Effects of sediment management on the amphipod community off the Latium coasts (Tyrrhenian Sea) and preliminary DNA barcoding data on Ampelisca (Amphipoda)

Macroinvertebrates are commonly used as environmental indicators in monitoring programs. Among crustaceans, amphipod communities play a relevant role in describing changes of sea bottom features, being therefore well appreciated as indicators. In this study the effects of sediment management off the Tyrrhenian coasts of Latium (Central Italy) have been assessed, using amphipod assemblages to monitor changes occurred in soft bottom areas before and after the perturbation. Results showed a variation in number of both individuals and species, with Ampelisca brevicornis (Costa, 1853), A. diadema (Costa, 1853), A. typica (Bate, 1856) and A. tenuicornis Liljeborg, 1855 as the most abundant species before sediment management, and Autonoe spiniventris Della Valle, 1893, Urothoe pulchella (Costa, 1853) and Medicorophium runcicorne Della Valle, 1893 as the most abundant ones after the perturbation. Amphipod assemblage appeared modified after sediment management showing an increase of species linked to sandy substrates. It is known that amphipod species have different degrees of sensitivity to environmental impacts but deeper studies concerning single species are problematic, also because of the limitation of a correct taxonomic classification of specimens based on morphological characters. With the aim to set up a tool for a quick and reliable assignment of the abundant genus Ampelisca, we have carried out a preliminary survey of a 658 bp (base pair) fragment of the mitochondrial cytochrome oxidase I (COI) gene, showing that some possible mis-assignments can occur based only on morphological characters.

Infaunal macrobenthic community dynamics in a manipulated hyperhaline ecosystem: a long-term study

BackgroundUnderstanding the responses of ecological communities to human-induced perturbations is crucial for establishing conservation goals. Ecological communities are dynamic entities undergoing fluctuations due to their intrinsic characteristics as well as anthropogenic pressures varying over time. In this respect, long-term studies, based on large spatial and temporal datasets, may provide useful information in understanding patterns and processes influencing the communities’ structure. Theoretical evidence suggests that a role of biodiversity is acting as a compensatory buffer against environmental variability by decreasing the temporal variance in ecosystem functioning and by raising the level of community response to perturbations through the selection of better performing species. Therefore, the spatial and temporal changes in the specialization of the community components may be used as an effective tool to monitor the effects of natural and anthropogenic alterations of the environment in dynamic systems. We examined the temporal dynamics of macroinvertebrate community structure in the hyperhaline habitat of Tarquinia Saltworks (central Italy). We aimed at: (i) investigating the relationships between the level of community specialization and the alterations of the environment across fourteen years; (ii) comparing the ability of aggregate community parameters such as the average abundance vs. species specialization in describing patterns of community composition.ResultsWe arranged the data in three sub-sets according to three periods, each characterized by different environmental conditions. The mean abundance of sampled macroinvertebrates showed a significant change (p < 0.01) only in the community inhabiting the saltwork basin closely connected to the sea, characterized by the highest environmental variation (i.e. the coefficient of variation, CV, of the aggregate environmental variability over the study period, CVrange = 0.010 - 0.2). Here we found marine species like Modiolus adriaticus (Lamarck, 1819), Neanthes irrorata (Malmgren, 1867), and Amphiglena mediterranea (Leydig, 1851), which inhabited the saltworks during the halt period but disappeared during the subsequent eutrophication phase. Conversely, species specialization showed a significant decrease for each sampled community in the presence of habitat degradation and a recovery after ecological restoration. The widest fluctuations of specialization were recorded for the community inhabiting the saltwork basin with the highest long-term environmental variability.ConclusionsRecent advances have shown how the increased temporal and spatial variability of species’ abundance within the communities may be a signal of habitat disturbance, even in the absence of an apparent decline. Such approach could also be used as a sensitive monitoring tool, able to detect whether or not communities are subjected to increasing biotic homogenization. Also, the increased functional similarity triggered by habitat degradation may impact on species at higher trophic levels, such as the waterbirds wintering in the area or using it as a stopover during migration.

Dietary antioxidants, food deprivation and growth affect differently oxidative status of blood and brain in juvenile European seabass (Dicentrarchus labrax)

Compensatory growth may increase molecular oxidative damage, which may be mitigated through the intake of dietary antioxidants. However, dietary antioxidants may also reduce concentration of antioxidant enzymes, which have a key role in regulating the oxidative status. Here we investigated whether feeding on a diet rich in antioxidants (vitamin E) enables juvenile European seabass (Dicentrarchus labrax) to catch up after a period of food deprivation with negligible effects on the oxidative stress to blood and brain as compared to fish feeding on a normal diet (i.e., not enriched in antioxidants). The results show that a higher intake in antioxidants favoured compensatory growth, but this came at a cost in terms of increased oxidative damage. Increased intake of antioxidants also resulted in changes in the activity of enzymatic antioxidant defences and increased protein oxidative damage in both brain and blood. In addition, food deprivation caused increased protein oxidative damage in brain. Our findings show that the beneficial effects of dietary antioxidants on growth may be offset by hidden detrimental effects and that different early life events affect different components of oxidative status of a given tissue.

Seasonal patterns of floating macro-litter across the Western Mediterranean Sea: a potential threat for cetacean species

Marine litter is a major form of pollution in the Mediterranean, but despite legislative requirements, additional information is still needed to evaluate basin-scale amounts, trends, and potential threats for the biota, especially for Habitats Directive listed species, such as cetaceans. Through repeated sampling of floating macro-litter along a fixed transect between Spain and Italy, this study provided detailed data within four marine sectors of the Western Mediterranean Sea, characterized by seasonal variability in oceanographic/ecological conditions and anthropogenic pressure. Moreover, we identified the areas of major overlap between high density of plastic and cetacean sightings. Litter was composed of plastic for more than 65%, with more diverse compositions occurring in the Balearic and Sardinian Sea compared to the semi-enclosed Bonifacio and Tyrrhenian sectors. The average amount of macro-litter ranged between 1.9 and 2.8 items km−2 and reached the highest values in spring/summer in all basins, suggesting a relationship with the increasing of touristic and maritime activities, both in coastal and offshore waters. The Balearic and Bonifacio sectors showed higher amounts and larger accumulation areas for plastic, likely due to a combination of multiple sources and oceanographic processes influencing the distributional patterns. Cetacean sightings were recorded in all sectors with fin whale (Balaenoptera physalus) and striped dolphin (Stenella coeruleoalba) as the most frequent species. The presence of cetaceans in areas with high densities of plastic emerged mostly during spring/summer in the Balearic and Bonifacio sectors, but other specific areas of potential exposure were identified, indicating the need for a dynamic definition of this threat.

Environmental heterogeneity promotes microgeographic genetic divergence in the Mediterranean killifish Aphanius fasciatus (Cyprinodontidae)

Environmental stress can promote evolutionary forces and genetic divergence, but at which microgeographic scale divergence may arise, even in the presence of gene flow, remains poorly known. We studied the effects of eutrophication in a saltwork over a period of 6 years on the gene pool of a local population of the Mediterranean killifish Aphanius fasciatus, a species resistant to extreme conditions. We hypothesised that during eutrophication, the environmental stress may have acted differently along a gradient of salinity and oxygen concentration in promoting evolutionary forces, generating divergence over a small spatial scale (2 km), despite gene flow. We analysed 24 allozymes in three temporal samples each composed of four spatial sub-samples, collected along the gradient, during eutrophication (2003 and 2005) and after a recovery project (2008). The results suggest that eutrophication promoted natural selection, originating a genetic cline on one locus (adenosine deaminase) significantly linked to salinity and oxygen concentration. Together with selection, both genetic drift and gene flow contributed to shaping the genetic structure under stress by further promoting the genetic heterogeneity and giving rise to deficits of heterozygotes as a secondary effect of the divergence. Environmental stress thus increased diversification, with the effects of selection and drift prevailing on gene flow. When environmental stress was relaxed (2008), allele and genotype frequencies became homogeneous, likely because under less extreme conditions the gene flow prevailed. These results improve our understanding of microgeographic divergence, and highlight the role of environmental stress in moulding microevolutionary dynamics and genetic patterns of animal populations.