Genomic and transcriptomic approaches have the potential for unveiling the genome-wide response to environmental perturbations. The abundance of the catadromous European eel (Anguilla anguilla) stock has been declining since the 1980s probably due to a combination of anthropogenic and climatic factors. In this paper, we explore the transcriptomic dynamics between individuals from high (river Tiber, Italy) and low pollution (lake Bolsena, Italy) environments, which were measured for 36 PCBs, several organochlorine pesticides and brominated flame retardants and nine metals. To this end, we first (i) updated the European eel transcriptome using deep sequencing data with a total of 640,040 reads assembled into 44,896 contigs (Eeelbase release 2.0), and (ii) developed a transcriptomic platform for global gene expression profiling in the critically endangered European eel of about 15,000 annotated contigs, which was applied to detect differentially expressed genes between polluted sites. Several detoxification genes related to metabolism of pollutants were upregulated in the highly polluted site, including genes that take part in phase I of the xenobiotic metabolism (CYP3A), phase II (glutathione-S-transferase) and oxidative stress (glutathione peroxidase). In addition, key genes in the mitochondrial respiratory chain and oxidative phosphorylation were down-regulated at the Tiber site relative to the Bolsena site. Together with the induced high expression of detoxification genes, the suggested lowered expression of genes supposedly involved in metabolism suggests that pollution may also be associated with decreased respiratory and energy production.

The European eel Anguilla anguilla is thought to be in a multi-decadal decline across its range. Although its northern Atlantic sub-populations are well-studied, little is known about the historical trend and current status of eel stock in the Mediterranean Sea. To fill this gap, we gathered catch data for 86 lagoon fisheries in nine countries across the Mediterranean basin and analysed historical trends and geographical and environmental patterns. We found a region-wide decline in eel catch, beginning in the mid-1970s and exceeding the simultaneous decline in non-eel fisheries, as well as lower productivity in larger lagoons and those in the southern Mediterranean. Additionally, we developed a population dynamics model to provide a preliminary estimate of pristine, potential, and actual escapement of spawning adults (silver eels) across the Mediterranean basin under historical and current conditions. Model results suggest that current escapement is 35% of escapement at pristine biomass levels, <40% target set by EC regulation 1100/2007. Furthermore, we estimate that a complete closure of lagoon fisheries would achieve 57% of pristine escapement under current recruitment levels. Though preliminary, this analysis represents a first step towards a full assessment of the role of the Mediterranean sub-population in overall eel stock recovery.

European consumers prefer wild over farmed aquatic food and consider it healthier and tastier. Consumers are increasingly paying attention to sustainability and welfare of farmed fish. Such expectations might be met by organic certification, but this represents a cost for the producer. It is crucial to know consumer habits about farmed aquatic food consumption and willingness to pay for certification. Data about Italian consumers’ preferences regarding farmed organic aquatic food were collected by an online questionnaire. A total of 8,657 answers were analyzed, patterns associated with demographics were investigated, and the degree of correlation among answers was calculated. The majority (75%) of family units buy less than 2 kg of farmed aquatic food per month, spending on average 20–50 €. About 40% never consume organic aquaculture products because of lack of knowledge, unavailability, and high price. Slightly over half (55%) of consumers, regardless of age, sex, and area, were willing to pay a premium price for organic-certified aquatic food, seen as antibiotic free, traceable, and sustainable. Organic food in general is well known, and distrust is the main reason that consumers avoid it, while organic aquatic food is still in its infancy, and lack of knowledge is associated with low consumption.

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—10%, 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—10%) 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’ number was observed with the diet containing microalgae. Fish fed poultry by-product meal were characterized by the lowest yellow pixels’ 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.