Anguilla Anguilla Research Articles

Participatory stock assessment in West Java contributes to the management of glass eel fisheries in Indonesia

Following the decline of Japanese eel catches and the EU European eel trade ban, other regions, such as Southeast Asia, have become increasingly important sources of juvenile anguillid species for aquaculture. Although appropriate fishery management of tropical eel species is urgently required, data collection by the government or scientific authorities is extremely difficult, because tropical glass eel fisheries are small-scale fisheries conducted in the Global South, where expertise and resources are sometimes limited. To collect data on glass eel fisheries, participatory stock assessments were conducted in West Java, Indonesia, where a Fishery Improvement Project (FIP) and an Aquaculture Improvement Project (AIP) were launched in collaboration with industries, middlemen, fishermen, NGOs, national and local agencies, and scientists. This participatory study successfully collected data on more than 3000 daily fishing practices from approximately 400 fishermen in a single water system in 2019. Even though the assessment was not species-specific, the data collected allowed estimation of the natural mortality rate as being 0.011 day−1. The annual exploitation rate of the glass eel fisheries was estimated as 24.9%, based on a generalised depletion model developed for the data-limited situation where only fishery catch and effort data are available. The data collection scheme for glass eel fisheries was disseminated by local and national agencies to glass eel fishermen in Indonesia and contributed to developing the Eel Conservation National Action Plan.

“Missing the Trees for the Forest?” An Analysis of the Harms to European Eels Caused by Their Trafficking and Trade

Wildlife trafficking has generally been studied for its harm to humans, to species of nonhuman animals, and to ecosystems. Such approaches fail to recognize the intrinsic value of nonhuman animal life. As discussed by various authors, even biodiversity loss discourses tend to adopt a human-centered perspective which overlooks the suffering of those individual nonhuman animals who are trafficked and traded. Through a case study of the European eel based on data collected through interviews, observation, and document analysis, this paper exposes the demand for European eels and the harms caused to them throughout the supply chain. Moreover, using a visual approach to green criminology, the research employs photographs as evidence of harm. By doing so, the paper makes visible the impact of wildlife trafficking and trade on European eels. As the research shows, European eels suffer along the supply chain not only when they are trafficked, but when they are subjected to a legal trade.

Exploring Perfluoroalkyl Substances (PFASs) in Aquatic Fauna of Lake Trasimeno (Italy): Insights from a Low-Anthropized Area.

This study investigated the concentrations and profiles of 19 perfluoroalkyl substances (PFASs) in the muscle and liver of four freshwater species from Lake Trasimeno (Italy): Anguilla anguilla (European eel), Carassius auratus (goldfish), Perca fluviatilis (European perch), and Procambarus clarkii (red swamp crayfish). In livers, the amount of PFASs ranged from 3.1 to 10 µg kg-1, significantly higher than that in muscle (0.032-1.7 µg kg-1). The predominant PFASs were perfluorooctane sulfonic acid (PFOS) and long-chain carboxylic acids (C8-C14). Short-chain compounds (C4-C5), as well as the long-chain sulfonic acids (C9-C12), were not quantified. The contamination patterns were similar among species with few differences, suggesting the influence of species-specific accumulation. The PFAS concentrations in livers were comparable among species, while in muscle, the higher values were measured in European eel, followed by goldfish, European perch, and red swamp crayfish. The levels were generally lower than those reported for fish from Northern Italian lakes and rivers. The concentrations of regulated PFASs were lower than the maximum limits set by Regulation EU 2023/915 and did not exceed the Environmental Quality Standards (PFOS in biota). This study provides the first valuable insights on PFASs in freshwater species from Lake Trasimeno.

The Presence of Bioactive Compounds in European Eel (Anguilla anguilla) Skin: A Comparative Study with Edible Tissue.

The presence of bioactive compounds in European eel (Anguilla anguilla) skin was studied. Proximate and lipid class compositions and analysis of the fatty acid (FA) profile (individual FAs; FA groups, i.e., saturated, monounsaturated, and polyunsaturated; FA ratios, i.e., polyunsaturated/saturated, ω3/ω6) were determined and compared to the composition of the eel muscle. As a result, higher (p < 0.05) levels of proteins (271.6 g·kg-1), lipids (38.0 g·kg-1), ash (27.7 g·kg-1), and ω6 FAs were observed in the skin tissue. Contrary, the muscle tissue showed higher (p < 0.05) moisture, ω3 FA, and ω3/ω6 ratio values. Regarding lipid classes, a higher (p < 0.05) proportion of phospholipids (111.1 g·kg-1 lipids), free sterols (104.7 g·kg-1 lipids), α-tocopherol (274.0 mg·kg-1 lipids), and free FAs (43.6 g·kg-1 lipids) was observed in the skin tissue. No differences (p > 0.05) between both tissues could be detected for triacylglycerol and FA group (saturated, monounsaturated, and polyunsaturated) values and for the polyunsaturated/saturated FA ratio. It is concluded that European eel skin, a by-product resulting from commercial processing, can be considered a valuable source for the food and pharmaceutical industries by providing value-added constituents such as proteins, lipids, ω3 FAs, phospholipids, and α-tocopherol.

Effects of European eel egg and larval stocking density on rearing water, offspring bacteriome and derived immune response

If human exploitation of the “critically endangered” European eel (Anguilla anguilla) is to continue, the eel's life cycle in captivity must be closed and techniques established to produce viable offspring in hatcheries. Despite stable offspring production, high mortality rates during early developmental stages have hindered progress in closing the lifecycle in captivity. We hypothesised that mortalities affecting embryos and newly hatched larvae, when the immune system is expected to play a vital role in protecting the offspring, could be linked to adverse microbial conditions arising in high-density rearing. We therefore set out to explore the bacteriome changes in rearing water and offspring as well as the molecular immunologic development of offspring at different initial stocking densities (500, 1000, 2000, and 4000 eggs/L) from fertilisation to 3 days post-hatch (dph). The lowest density resulted in ∼5% higher survival. Independent of density, most mortality (∼75%) occurred during embryonic rather than larval development. The bacteriomes of both offspring and rearing water differed according to stocking density, with a potentially healthier bacteriome at the lowest density, marked by greater ASV richness and abundance from various phyla (Proteobacteria, Actinobacteria, Fusobacteria, and Firmicutes). In contrast, the bacteriome of the highest density was dominated by Proteobacteria ASVs, including the potentially harmful Vibrionales order. We observed stage-specific bacteriome changes in offspring, transitioning from an inherent and balanced bacteriome in unadulterated eggs to a dominance of rapid-growing opportunistic bacteria in embryos (48 hpf), and finally to a more diverse bacterial community in larvae (3 dph). Thus, host-microbe interactions appear to significantly impact the overall high mortality observed during embryonic development. As the expression of stress and immune related genes was not affected by density, it seems that the molecular immune system was incapable of handling microbial interference during these early stages, aggravating the challenges faced during hatchery production. We conclude that low-density (500 eggs/L) incubation is a valid strategy to improve survival. However, high stocking densities (up to 4000 eggs/L) might be an acceptable compromise allowing more efficient utilisation of infrastructure and labour. At 4000 eggs/L, survival was reduced by only ∼5%, while there was no effect on hatching success and no cellular stress response. Nevertheless, bacterial community management tools should be in place during high-density incubation to avoid r-selection and thus counter bacteria-associated mortality.

Animal bioenergetics: Thermodynamic and kinetic analysis of growth and metabolism of Anguilla anguilla

Bioenergetics and biothermodynamics are valuable tools in research on growth and metabolic processes of a wide range of organisms, including viruses, bacteria, fungi, algae and plants, as is shown by the many publications on this topic in the literature. These studies provide insight into growth and metabolism of individual species, as well as interactions between species, like the virus-host interaction (infection) and virus-virus interaction (competition). However, this approach has not yet been applied to animal species. The universality of biothermodynamics and bioenergetics provides a good motive to apply them in analysis of animals. In this research, we made a bioenergetic, biothermodynamic and kinetic characterization for the first time for an animal species – Anguilla anguilla L. (European eel). We made a comparative analysis on yellow (young adult) and silver (mature adult) phases. Metabolic processes were modeled as chemical reactions with characteristic thermodynamic properties: enthalpy, entropy and Gibbs energy. Moreover, Gibbs energy explained growth rates, through phenomenological equations. This analysis of animal metabolism and growth explained metabolic properties of yellow and silver A. anguilla, including the bioenergetic aspect of life history. Moreover, we compared thermodynamic properties of A. anguilla with those of its main macromolecular components and other organisms. The thermodynamic properties were explained by the structural properties of organisms. This research extends the bioenergetic and biothermodynamic approaches to zoology, which should allow analysis of the energetic aspect of animal metabolic processes, interactions with their environment and interactions with other organisms. Furthermore, it connects the macroscopic perspective of zoology with the microscopic perspectives of biochemistry, bioenergetics and biothermodynamics. This will provide a basis for development of mechanistic models of animal growth and metabolism.

The inadequacies of estimating silver eel escapement by studying yellow eels caught in the coastal sea far away from the river mouth. A comment on Rohtla et al. (2021)

Abstract For the conservation and management of the critically endangered European eel, it is crucial to maintain an overview on the biomass of the eels moving from freshwater feeding areas to the sea for spawning. Rohtla et al. suggested an assessment of the escapement of eels from the Narva River to the Baltic Sea based on their study of origin of yellow eels from Estonian coastal areas and eels from Finnish coastal areas. Silver eels from the Estonian coast have not been included in the study. The number of descending eels in the Narva River has not been investigated. The sampling areas in the sea were located far from the river mouth, ranging from 100 to 500 km away. The article does not include an analysis of how to calculate the number of eels descending from the river based on the samples used. Thus, estimates can be significantly biased. We demonstrate that the approach used to estimate escapement is methodologically incorrect and needs further development before applying in eel management. This comment recommends methodological improvements for estimating eel escapement using the indirect method.

Reply to: Tuvikene et al. The inadequacies of estimating silver eel escapement by studying yellow eels caught in the coastal sea far away from the river mouth. A comment on Rohtla et al. (2021)

Abstract Restocking European eel (Anguilla anguilla) is generally considered as a conservation action, but its true conservation value remains unknown and is currently debated over. Estimation of the biomass of escaping silver eels is one way to partially measure the success of restocking. Tuvikene et al. in a comment to Rohtla et al. criticize the data that were used to reach the conclusion that eel conservation goals in a fully restocked eel management unit in Estonia are not being met. While acknowledging some potential and unavoidable sampling biases in our study that need to be addressed in the future, we stand by our general conclusions.

Glass eel migration in an urbanized catchment: an integral bottleneck assessment using mark-recapture

Diadromous fish such as the European eel (Anguilla anguilla L.) are hampered by a high density of barriers in estuaries and freshwater systems. Modified and fragmented waterbodies lack tidal flows, and habitat may be less accessible and underutilized compared to free-flowing rivers and estuaries. With rising sea levels and increased occurrence of droughts, the number of barriers may further increase, implying that the need to study migration in such areas may even become more urgent worldwide. To study glass eel migration and behaviour in such highly modified water systems, a mark-recapture study was carried out in the North Sea Canal (NSC) basin, which drains into the North Sea via a large sluice complex. In total, eight uniquely tagged groups (3,797 glass eels) were released near the sluice complex, and 11 groups (2,663 glass eels) were released at inland barriers upstream over a 28 km long stretch in the NSC in spring 2018. The sluice complex attracted 10.3 million glass eel and did not block or delay their immigration. The large and diurnally intensively used coastal ship locks and allowings some saltwater intrusion, efficiently facilitated glass eel migration. Once in the NSC, water outlets from adjacent polders attracted glass eels relative proportional to the discharge of pumping stations. In the NSC, average migration speeds of 0.7 km/day (max. 1.8 km/day) were measured, and this increased with higher temperatures. Redistribution of glass eel from accumulations at inland barriers to other outlet locations was observed in both upstream and downstream directions in the NSC. Passage success and residence time (‘delays’ of 4.1–13.7 days) varied between the different inland barriers. Most of the glass eel, however, appears to settle in the easily accessible habitats within the brackish NSC catchment. This study combined an integral assessment of successive bottlenecks in a modified inland water system.

Silvering process of female European eel in the north Adriatic: Who is really ready to migrate?

During the 1970s and 2010, the population of Anguilla anguilla declined significantly, and the species is now classified as a critically endangered species by the International Union for Conservation of Nature (IUCN). Considering its social, economic, and ecological importance, it is necessary to understand the biological mechanism that controls population dynamics, in particular the passage from the resident phase to the migratory phase. During this phase of their life cycle, the environment plays a key role in the maturation of the spawners which will eventually undertake a long spawning migration to the Sargasso Sea.An assessment of the morphological characteristics of eels during their silvering process and reproductive activity was conducted by collecting 1513 female eels from seven lagoons in the North Adriatic Sea.Morphometric analyses show that eels classified as pre-migratory according to the Silver Index are histologically (65% of eels with oocytes in the most advanced stage of development) and morphologically ready to migrate. Accordingly, pre-migrant eels treated with hormone induction performed similarly to migrant eels. They mated and spawned spontaneously in the tank with a percentage of 81.0%, and 88.2% of them produced viable eggs. The results showed how the North Adriatic lagoons could present favourable conditions that permit the fast development of females with high reproductive potential. This data can be used to develop successful strategies to conserve and manage eel populations.

Effect of Food Amounts on Larval Performance, Bacteriome and Molecular Immunologic Development during First-Feeding Culture of European Eel.

Production of European eel offspring has become a reality, but liquid diets during larval culture hold new challenges. This study focused on increasing food amounts without compromising well-being or healthy larvae-bacteria interactions. First-feeding larvae were fed two food amounts (Low = 0.5 mL food/L water vs. High = 1.5 mL food/L water) until 30 days post-hatch (dph). Results indicated that ~75% of larvae ingested the diet in both treatments, but upregulation of a stress/repair-related gene (hsp90) on 25 and 30 dph indicated nutritional inadequacy. Larvae fed a High amount of food were 3.68% bigger, while larvae in the Low-food group showed 45.2% lower gut fullness and upregulated expression of the gene encoding the "hunger hormone" ghrelin (ghrl), indicating signs of starvation. The High-food group larvae exhibited a healthier bacteriome with a higher abundance of potentially beneficial orders (Lactobacillales and Bacillales), whereas the Low-food group showed more potentially harmful orders (Vibrionales, Rhodobacterales, and Alteromonadales). While survival was initially lower in the High-food group, both treatments had comparable survival by the end of the experiment. In conclusion, feeding European eel larvae with High food amounts seemed beneficial, supported by increased gut fullness, reduced ghrl expression (no starvation), enhanced growth, and the presence of a healthier bacteriome.

Effect of seawater temperature and pH on the sperm motility of the European eel.

The current climate change situation could bring critical effects for marine species, especially those already considered endangered. Although some species can adapt fast to the environmental changes, it is necessary to get into the worst scenario and develop tools to anticipatedly assess the physiological effects of such environmental change. With this purpose, our study aims to determine the effect of a range of seawater temperatures and pHs on sperm motility in the European eel (Anguilla anguilla). Low seawater pH (6.5-7.4) decreased the eel sperm motility in comparison to the control (pH = 8.2). We also studied the combined effect of the pH of the artificial seminal plasma (the plasma where the sperm cells are suspended) with the pH of Artificial Sea Water (ASW, pH 7.8 or and 8.2). We did not find statistical differences in sperm motility and kinetic parameters caused by the artificial seminal plasma pH. However, seawater pH induced significantly higher values of total sperm motility, and the percentage of fast spermatozoa with a pH of 8.2 in comparison with a pH of 7.8. In contrast, the seawater temperature did not affect sperm motility parameters or sperm longevity. To study the effect of the interaction between seawater temperature and pH on sperm motility, two temperatures: 4 and 24°C, and two pHs 7.8 and 8.2, were tested. There were significant differences between temperature and pH in several kinetic parameters and, in general, the lowest values were observed in the samples activated at low temperature and low pH (4°C, pH 7.8). This work suggest that eel sperm motility and kinetics will not be affected by the expected changes in pH or temperature due to the climate change.

Searching for the critically endangered European eel in oceanic islands: A pioneer study in the freshwater systems of Madeira, Macaronesia

Abstract The globally threatened European eel (Anguilla anguilla) is the only freshwater fish native to Macaronesia. Despite being a keystone species to freshwater habitats, little is known about its population, environmental associations and conservation requirements in oceanic islands. The density and geographical‐related factors influencing the distribution of A. anguilla in the subtropical Archipelago of Madeira (Portugal) were examined. Data on the species occurrence was initially collected using an online survey addressed to citizens. Eels were then sampled through electrofishing in 31 sampling sites along 11 streams on Madeira Island, and eel‐habitat associations were investigated using LMMs and GLMMs. One stream was also sampled in Porto Santo Island. The presence of A. anguilla was confirmed in the two islands of the archipelago with streams (Madeira and Porto Santo). Eels are distributed throughout Madeira Island, being more abundant – particularly small size individual– at lower altitudes (mostly below 150 m). The number of weirs was an important predictor of eel density, suggesting that these flood‐control structures limit their upstream migration. This study represents a pioneer sampling effort of the European eel in Madeira and results provide much‐needed baseline information on the species distribution and related environmental factors in oceanic islands. While most eel research has historically focused on mainland habitats where dams pose a significant threat to eel habitats, our study underscores the critical importance of addressing smaller, often overlooked barriers that may also cause habitat fragmentation. The European eel is a panmictic species, thus, the conservation of the Macaronesian subpopulations can have substantial benefits for its global recovery. A comprehensive investigation of the impact of man‐made obstacles on eel habitat is still needed. Similarly, other common threats such as interactions with non‐indigenous species and infection by Anguillicola crassus should be a research priority in future studies.

Glass eels at the continental edge of Europe: revisiting catchment recruitment at the international River Minho/Miño

The glass eel catch from the international River Minho, western Iberian Peninsula, forms the southernmost Atlantic series in the composite index outside the North Sea assessing European eel recruitment. Here, new experimental yield data from the lower estuary (1981–2022) and fishers´ daily records (1990–2022) were modelled to describe and compare seasonal and interannual trends. Seasonality matched river discharge climatology, possibly a more general feature in the southern range of the species distribution, with the difference between high and low season becoming less marked in recent periods of lower abundance. Glass eel yield showed a sharp decline during the 1980s, in line with the recruitment index outside the North Sea and with total Minho catch, but not with recent local estimates of catch per unit effort. This decline is corroborated by trends in fishers´ daily records, suggesting that the reduction in effort in the Minho was the consequence of a gradual adjustment to recruitment in the catchment mediated by progressively tighter local management measures. The inefficiency of fisheries regulatory measures to guarantee stock recovery alone calls for more comprehensive measures to reverse anthropogenic impacts on continental eel populations, but the task seems Herculean.

Social network analysis as a tool to inform anguillid eel conservation and management

Abstract Eel Management Plans demand European silver eel (Anguilla anguilla) escapement to the sea of at least 40% of that expected historically in the absence of human impacts. Landlocked lentic waterbodies, such as drinking water reservoirs, host substantial numbers of eel, which could represent a significant contribution to catchment-based conservation targets. To optimize netting strategies for eel management policies, information on their aggregation behaviour is currently needed but lacking. We performed a fine-scale acoustic tracking study to monitor the movements of 86 European eel in a UK reservoir. Social network sampling and sensitivity analyses were used to assess whether eel aggregate at scales relevant for current capture techniques. European eel were found to aggregate at spatial and temporal scales of 50 m and 2 days, respectively, which complements current capture methodologies and recommendations. Aggregations were not driven by fixed resources, indicating that other factors, such as sociality, may drive aggregation behaviour. Results also show that current netting practices could be optimized by increasing netting lengths from 50 to 80 m. In addition to aiding conservation and management protocols, these results provide an ecological foundation for exploring the role of social behaviour in this Critically Endangered species.

The Influence of Natural and Anthropogenic Environmental Pressures on European Eel Abundances in French Estuaries

The aim of this study was to investigate the influence of environmental characteristics and anthropogenic pressures on the abundance of estuarine European eels (Anguilla anguilla L.) during their continental growth phase. European eels were collected with fyke nets from spring to autumn in twenty-nine estuaries along the French English Channel and the Atlantic coast. Eel abundance (catch per unit effort, CPUE) was assessed for all eels and by size class for small (total length &lt; 300 mm), intermediate (≥300 to &lt;450 mm), and large (≥450 mm) eels. The environmental characteristics of the French estuaries were described by twelve descriptor variables, mainly related to hydro-morphological and sedimentary factors. Based on principal component analysis and hierarchical clustering analysis, estuary size was identified as the main explanatory variable and used to compare eel abundance. Eel abundance differed significantly according to estuary size, with higher abundances observed in small estuaries (7.22 to 13.00 ind. fyke nets 24 h−1) compared to large estuaries (0.13 to 0.71 ind. fyke nets 24 h−1). Spatial variation in eel abundance was correlated with differences in estuary size for all eel size classes. The influence of anthropogenic pressures on eel abundance was assessed by nine anthropogenic estuarine pressure indicators. The results indicate that high values of the anthropogenic pressure indicators were correlated with low eel abundance. This study highlights that large French estuaries subject to stronger anthropogenic pressures were less favourable habitats than small estuaries with less anthropogenic pressure.

Reaching the steady state: 30 years of Anguillicola crassus infection of European eel, Anguilla anguilla L., in Northern Germany.

A 30 years long data series on the infection dynamics of European eel (Anguilla anguilla L.) with the non-native invasive nematode Anguillicola crassus Kuwahara, Niimi & Hagaki, 1974 is presented. Parasite burden was evaluated for 30 years in inland and coastal waters in Mecklenburg-Western Pomerania from 1991 to 2020. The total prevalence, mean intensity and damage status of the swim bladders were very high during the first decade (1991–2000), and significantly decreased in both marine and freshwater eel populations in the following decades (2001–2010, 2011–2020). The parasite intensity of eels in coastal waters was significantly lower compared with the freshwater systems (61.3% vs 79.5% in the first decade), indicating the vulnerability of the parasites to brackish water conditions and the fact that the life cycle of A. crassus cannot be completed under high saline conditions. Eel caught in the western part of the Baltic Sea (west of Darss sill) had the lowest mean infection (51.8% in first decade) compared to the eastern part with 63.8%. Thus, besides different infection patterns caused by the environmental conditions, a temporal trend towards a reduced parasite intensity and a more balanced parasite–host relationship developed in the 30 years of interaction after the first invasion. Possible reasons and mechanisms for the observed trends in parasite–host interactions are discussed.

Optimizing the mass marking of fish with alizarin red S: an example with glass eels.

Fish marking is an essential tool for fisheries management, especially for evaluating the stocking of endangered fish species to support conservation and sustainable use of fish stocks. Batch marking of young European eels Anguilla anguilla (L.) prior to stocking is recommended as the benefits of stocking for the spawning stock can be evaluated by recapturing marked fish over time, therefore mass marking of young eels with substances such as alizarin red S (ARS) is becoming increasingly important. To improve the marking method and reduce marking costs when immersing glass eels in an ARS solution, eight laboratory experiments under varying conditions (e.g., temperature, ARS concentration, immersion time, osmotic induction, fish density) and with ARS from different suppliers were carried out. The results show that optimal marking of glass eels can be carried out in the field or during transport by putting approximately 50 g of glass eels per liter in 150 mg L-1 ARS solution for 3 h at 10-15°C. Lower concentrations did not result in reliable marking. Water temperatures of 5°C and below can have a stunning effect on the eels and increase mortality significantly, regardless of the concentration of ARS. Glass eel densities below 50 g L-1 in the marking bath increase marking costs unnecessarily, while a higher density of 100 g L-1 resulted in significantly higher mortality and lower marking success. A somewhat more difficult but less expensive alternative is to bathe the fish in a saline solution of 1% (10 PSU) of 80 mg L-1 ARS for 3 h at 10°C. Costs can also be significantly reduced by choice of supplier for ARS, but care should be taken as the quality of the powder appears to vary (mean percentage of sufficiently marked eels ranged from 59% to 91% among suppliers in the present study) and can lead to marking failure. The optimal marking conditions can help ensure that stocked glass eels can be reliably identified in future studies to assess stocking benefits while reducing costs.

First data on morphometric parameters of the European conger eel (Conger conger, Linnaeus, 1758) in Béni-saf Bay (Western Algerian coasts)

A biometric study was conducted on a benthic fish of the family Congridae, the European conger eel (Conger conger Linnaeus, 1758), from the western coasts of Algeria, from Béni-Saf. This study was carried out due to the total absence of reliable and exploitable information concerning the morphometric characteristics of this fish along the Algerian coast. It was based on statistical processing of 18 morphometric variables measured on each sampled fish. the comparison between months using univariate ANOVA and multivariate MANOVA statistical tests showed significant differences in morphometric variables measured on the European conger eel (Conger conger). However, regarding the sex factor, no significant differences were observed between males and females.

Immune Defenses in European Eels (Anguilla anguilla) Post Exposure to Formalized Killed Bacterin of Vibrio vulnificus

Immune Defenses in European Eels (Anguilla anguilla) Post Exposure to Formalized Killed Bacterin of Vibrio vulnificus