Impact of Hermodice carunculata (Pallas, 1766) (Polychaeta: Amphinomidae) on artisanal fishery: A case study from the Mediterranean sea.

Invasive species can cause severe economic damages, ecosystem alterations, and can even threat human health. In the global warming scenario, which can act as a driving force for the expansion of thermophilic species, we investigated for the first time the economic damage caused by the invasive bearded fireworm, Hermodice carunculata, to artisanal longline fishery in the Mediterranean Sea. We focused on bottom longline fishery targeting the highly prized white seabream Diplodus sargus, investigating catch composition of the fishing gear and Catch Per Unit Effort (CPUE) of species caught, with particular emphasis on the economic damage caused by the bearded fireworm, H. carunculata, in relation to water temperature. Our results clearly indicated direct and indirect economic damage to fishing activities practiced in the southeastern coast of Sicily (Ionian Sea). Type and extent of the damage caused by the invasive worm (H. carunculata) were discussed in relation to temporal scale and overall yields obtained by this traditional artisanal fishery, and some solutions are proposed. However, the actual situation requires special attention because it is expected to worsen in the context of the global warming future scenarios, such that further studies are urgently needed.

Gradients of Variation in the At-Vessel Mortality Rate between Twelve Species of Sharks and Skates Sampled through a Fishery-Independent Trawl Survey in the Asinara Gulf (NW Mediterranean Sea).

Elasmobranchs are priority species for conservation due to their rapid decline determined by the unbalanced struggle between a fragile bio-ecology and strong anthropogenic impacts, such as bycatch from professional fishing. In this context, measuring species resistance to catch of poorly selective gear is of paramount importance. During June-October 2022, five experimental fishing campaigns were carried out in the Asinara Gulf (northern Sardinia) through 35 geographically and bathymetrically representative hauls of an area between 30 and 600 m in depth. Skates prevailed over sharks in the number of species, with seven and five species, respectively. We first evaluated the status of each individual with respect to stress due to the trawl's catch using a three-graded scale. We also recorded individual biometrics (total and disk length, weight and sex, and maturity for males) on board by implementing the best practices in manipulating individuals for physiological recovery and release at sea. After capture, skates resulted in generally better conditions than sharks, although deepwater species of both groups exhibited a worse state than coastal species. The estimated vitality rates also depended on the size of the individuals. This work provides standardized data on the intermingled effect of size, species type, and inhabited depth on the resistance response of some elasmobranch species against capture by trawl fishery activities.

Exploring fishing threat at fleet segment and subregional scale: Least expert knowledge and a resilience versus disturbance-based approach as conservation's tools for cartilaginous fish.

Based on an explorative but rigorous elicitation framework, we obtained the bycatch fishing probability at the fishing fleet segment level using expert estimates. Based on the knowledge of three scientific experts, we developed a new and creative structured method for smart and fast fishery-related risk assessments for species of high conservation concern. In order to test the method here propose, we applied it to 76 cartilaginous fish species (included in the IUCN Red Lists) and on five different fishing segments at both Italian and Mediterranean scale. The method produced qualitative results specific to the threat posed by fishing for each species and each segment with information between and within the segments. Based on the interpretation of resilience-disturbance interactions developed for ecological systems, the quantitative results provided reliable cumulative metrics, measuring the extinction risk due to fishing and the response to overfishing for the species considered. Additionally, the results highlight that the method perform best on a small geographic scale. Therefore, the application of this new method on other subregional or local scales where very few data are available (e.g., fishing effort) could be a valuable tool for the preliminary assessment for species of conservation concern. In fact, despite the absence of detailed catch data at local geographic scales, the flexibility of this method could help to highlight potential fishery-related conservation problems and thus redirect conservation strategies for threatened marine species such as many sharks and rays species.

Chemical and structural aspects of fresh and fossil marine mollusc shells investigated by mid-infrared and near-infrared spectroscopy with the support of statistical and multivariate methods.

In the present study, we applied Fourier transform infrared (FTIR) and Fourier transform near infrared (FTNIR) spectroscopy to investigate some specific structural aspects of Patella caerulea, Mytilus edulis, Ostrea edulis, and Calista chione shells sampled in different sites. Moreover, for Ostrea edulis and Calista chione, the present study also included fossil samples. As far as FTIR spectroscopy is concerned, the support of statistical and multivariate methods such as the average spectrum (AV), spectral deconvolution, and two-dimensional correlation analysis (2DCOS) allowed to detect structural differences existing within the same mollusc species as a function of the sites they come. These differences can be reasonably linked to the local environmental conditions, which affect the biomineralization pattern of shell formation and growth. These structural differences are related to the calcite, aragonite, Mg-calcite contents, and interactions, as presently observed for fresh and fossil shells. The application of 2DCOS and deconvolution to FTIR spectra also showed the role of the amorphous calcium carbonate (ACC) in the structural characterization of shells, then suggesting the use of a new parameter, the calcite and aragonite to ACC (CAACC) ratio, as a new measurement for the structural characterization of shells. At last, FTNIR spectroscopy allowed detecting the presence of α-helix and ß-sheet protein structures in the shells. The results of this study show that also FTIR and FTNIR spectroscopy are able to discern differences in structural characteristics of mollusc shells, a field of environmental studies where scanning electron microscopy and X-ray diffraction are the more widely used methods.

Macro-litter ingestion in deep-water habitats: is an underestimation occurring?

Marine litter affects marine organisms, posing threats to biodiversity conservation and to ecosystem structure and functioning. Providing a suitable assessment of marine litter effects on marine life through bioindicator species is crucial to drive an effective waste management policy. However, to date no standardized tool has been developed to describe and monitor the impact of marine macro-litter on marine life within deep-water habitats. Modifying the protocol proposed to monitor macro-litter ingestion by the loggerhead sea turtle Caretta caretta, we perform a preliminary investigation on the suitability of different elasmobranch species for monitoring macro-litter ingestion in deep-sea. A total of 122 specimens representing 7 elasmobranch species were collected and examined. External visual inspections documented no clear evidences of disease due to marine litter entanglement. A total of 7 ingested litter items were found in the stomach or in the esophagus of 6 specimens of 4 different species (frequency of occurrence = 4.9%), with a maximum number of 2 items per specimen. No litter items were found in the intestinal contents, as well as no evidence of gastrointestinal blockages due to litter items were detected. The low number of collected litter items suggests that the number of samples required is too large for a feasible monitoring program. Moreover, we observed that the anatomy of the intestinal spiral valve may represent an obstacle to the transit of macro-litter items, which could be spontaneously regurgitated as it happens in the selective elimination of undigested remains, such as bones and scales. Therefore, macro-litter retention time in the gastrointestinal tract of elasmobranchs could be brief and shorter than retention time of food. This may lead to an underestimation of macro-litter ingestion frequency by deep-water elasmobranchs. This study reports the first evidence of plastic ingestion by the kitefin shark Dalatias licha.

Food preference determines the best suitable digestion protocol for analysing microplastic ingestion by fish.

Microplastic presence in the marine environment has generated considerable concern. Many procedures for microplastics detection in fish gastrointestinal tract have been recently developed. In this study, we compared efficiencies of two common procedures applied for the digestion of organic matter (10% KOH; 15% H2O2) with a new proposal (mixture of 5% HNO3 and 15% H2O2). We considered ecological diversity among species and differences in their diet compositions as factors that could affect the efficiency and feasibility of analytical approaches. Our aim was to understand whether either one of the three protocols might be suitable for all species or it might be more advisable to select a method according to the gut content determined by different food preferences. The results showed that the trophic level and feeding habits should be considered for protocol selection. Finally, we applied the best protocols on samples from the Tyrrhenian sea.

Spatial variability and influence of biological parameters on microplastic ingestion by Boops boops (L.) along the Italian coasts (Western Mediterranean Sea).

Recently, many studies focus on the ingestion of microplastics by marine biota. Fish exploit almost every kind of marine environment, occupy many ecological niches and are an important food source for human populations worldwide. For these reasons, they seem to represent very appropriate biological indicators of microplastic ingestion. UNEP/MAP SPA/RAC (2018) identified the bogue, Boops boops (Linnaeus, 1758), as a possible target species for monitoring microplastic ingestion in fish populations. This study provides the first report of microplastic ingestion by B. boops from the Tyrrhenian and the Ligurian Seas (Western Mediterranean Sea). Generalized Linear Mixed Models were used to analyse the relationship among biological parameters and environmental factors. A total of 379 bogues were collected in three Italian regions, subject to different anthropogenic pressures (river input, human population, shipping lanes and distance from the coast). Microplastics were detected in the gastrointestinal tract of most individuals (56%) with a mean of 1.8 (±0.2) microplastics per individual. Our study further confirms that this species is able to highlight differences in the ingestion of microplastics according to local anthropization, resulting Latium region to be the most polluted. Fish with lower physical condition are more likely to ingest microplastics, suggesting a relationship with the level of local environmental contamination. Finally, the ingestion of microplastics might be influenced by behavioural differences between sexes. According to our results, males ingest significantly more microplastics than females (p < 0.05). Our research confirms that an extensive knowledge on the biology of a bioindicator species is a priority for developing a valid monitoring strategy, such as the Marine Strategy Framework Directive for European waters.

Exploring microplastic ingestion by three deep-water elasmobranch species: A case study from the Tyrrhenian Sea.

This study analyzes microplastic ingestion by three deep-water elasmobranch species (Galeus melastomus, Scyliorhinus canicula and Etmopterus spinax) from the Tyrrhenian Sea, discriminating between stomach and intestine contents. The absence of significant differences in frequency and abundance of plastic items into stomachs seems to suggest that ecological diversity among the three sharks does not strongly influence the probability of plastic ingestion in the study area. On the other hand, the detected differences in the microplastic content into the intestine might be due to a different retention time of microplastics, suggesting how feeding habits could influence metabolic features, and therefore affect the recovery of ingested plastic items. This information would improve the future development of marine micro-litter monitoring systems, following the MSFD requirements. Moreover, this study shows that all the three examined elasmobranch species can give important information even with relatively small sample sizes (N ≈ 30), and they could be used as target species for monitoring micro-litter ingestion in deep-water habitats.