european eel diet

04 dez european eel diet

Aquaculture 456, 50–61 (2016). Article  Monitoring EU decision-making process . These declines have been ascribed to overfishing, habitat degradation and changes in ocean currents (Van Ginneken & Maes 2005), the latter of which could decrease productivity and larval feeding opportunities in the spawning region (Friedland et al. OTUs only occurring once in the total dataset or which included <9 reads in total, were excluded, as were A. anguilla sequences, and any Actinopterygii OTUs with ≤2% (maximally 4 bp difference) dissimilarity to A. anguilla. R. Soc. Qualitative assessment of the diet of European eel larvae in the Sargasso Sea resolved by DNA barcoding. No significant correspondence between the number of different prey per larva and phytoplankton biomass, latitude, longitude, day/night capture, or larva size were detected, possibly reflecting the limited data available (electronic supplementary material, table S2). 66, 1913–1927 (1988). Miyazaki, S. et al. Subsequently, DNA was extracted from guts from 61 randomly selected A. anguilla larvae. Coloration varies, but most have grey, white, or brown colored skin. Sci. 5, 12 (2008). All extruded diets were well Scientific Reports For instance, the abundance of larval stages of Polychaeta, Chaetognatha, and the relevant groups within Crustacea, peaks in spring (Deevey 1971), when Anguilla eels spawn and also the time of our sampling. European eel. Merged reads were clustered to OTUs on a 97% identity level to the ARB-SILVA v119 database, removing chimeras in the process. Monogr. Diabetologia 55, 2285–2294 (2012). Agric. Res. Certain species hunt only a few types of prey, while others eat just about anything that they can snatch up. Google Scholar. They have a large, transparent, and laterally-compressed body form, and a protracted larval duration, possibly lasting for 17–28 months5. To increase the reference-database coverage, DNA from 14 genetically-confirmed fish specimens from 13 families, including 3 common eel families, was amplified with the same primers. Cardona, L., de Quevedo, Á., Borrell, I. J. Plankt. 3, 471–474 (2012). Scientific Reports Biol. Nucleic Acids Res. ADS  Diet-induced phenotypic plasticity in European eel (Anguilla anguilla). Miller, M. J. et al. magnoliophytes) are common in gene libraries from guts of plankton organisms33,34; however, at present we, and others35, suspect that they are potential contaminants and doubt that they originate from prey items. Marine snow aggregates were collected at 8 stations (Fig. The finding of a variety of prey items in the larval guts shows that the frontal zones provide ample feeding opportunities. Our findings of a potentially Hydrozoan-dominated diet are consistent with earlier studies suggesting that gelatinous zooplankton26,40, and Hydrozoa in particular25, could be of importance in the diet of young A. anguilla larvae in the Sargasso Sea. Limited insight into eel larvae feeding and diet prevents a holistic overview of the life-cycle of catadromous eels and an understanding of the ecological position of their early stages in marine waters. S2). Jacoby, D. & Gollock, M. Anguilla anguilla. PubMed  Adult eels subsequently undertake one-way migrations back to the Sargasso Sea8,9,10 to spawn and complete the cycle. Tesch, F. The Eel (Blackwell, Oxford, 2003). Google Scholar. We thank the captain and crew of HMS Vædderen for assistance with the sampling, C. Havel for drawings, and T. Bataillon for help with statistics. The 16S and 18S rRNA marker genes were examined with Illumina MiSeq to discern prokaryotic and eukaryotic compositions, respectively, of eel guts and marine snow aggregates, while Sanger sequencing of 18S rRNA genes from zooplankton specimens was used to generate the reference database. Eel feed may also contain ingredients such as binders, wheat, starch, soybean meal, corn, vegetable or animal fat, minerals and vitamins. National Institute of Aquatic Resources, Technical University of Denmark, Kemitorvet, Kgs, Lyngby, Denmark, Daniel J. Ayala, Peter Munk & Cornelia Jaspers, Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark, Regitze B. C. Lundgreen, Sachia J. Traving & Lasse Riemann, Evolutionary Ecology of Marine Fishes, GEOMAR - Helmholtz Centre for Ocean Research, Kiel, Germany, Department of Environmental Science, Aarhus University, Roskilde, Denmark, Department of Science and Environment, Roskilde University, Roskilde, Denmark, You can also search for this author in Read more Covid-19 statistics for the European School Luxembourg II. Ayala, D., Riemann, L. & Munk, P. Species composition and diversity of fish larvae in the Subtropical Convergence Zone of the Sargasso Sea from morphology and DNA barcoding. Cite this article. A low trophic position of Japanese eel larvae indicates feeding on marine snow. The present study evaluated the diet of larval European eel, Anguilla anguilla - a critically endangered species. A total of 19 of the 61 analysed larvae did not contain amplifiable prey items. Google Scholar. 72, 342–349 (2006). Lasse Riemann. 2A). Camp. Although 18S rDNA sequences from a wide variety of plankton organisms have been detected from the gut of the European eel (A. anguilla) leptocephali, gelatinous zooplankton (hydrozoan jellyfish) was suspected to be the major diet [ 12 ]. https://doi.org/10.1038/s41598-018-24388-x, DOI: https://doi.org/10.1038/s41598-018-24388-x, Scientific Reports J. Mar. PubMed Central  DNA was extracted from the remaining larval tissue for species identification of European eel larvae, based on analysis of the mitochondrial cytochrome b gene, the nuclear 5S rRNA gene and microsatellite genotyping. Meth. S2), nor with the major Hydrozoa biomass contributors, Hydromedusae (linear model, R2 = 0.01, p = 0.75, n = 13) or Siphonophorae (linear model, R2 = 0.04, p = 0.51, n = 13; Supplementary Fig. Google Scholar. The blocking primer was added at a ratio of 0.8:1 relative to the reverse primer, after trials to determine a sufficient host-blocking effect utilizing the least amount of blocking primer. The European Eel is largely nocturnal, resting under stones or burrowing into mud during the day, emerging at dusk in search of food. 6, 819–822 (2010). I. Article  The breeding places of the eel. J. Microbiol. Google Scholar. 1993; Mochioka & Iwamizu 1996). Lasse Riemann 1, *, Hanna Alfredsson 1, Michael. Legislative tools . The European Parliament is the EU's only directly-elected institution. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. Mar. Proc. Sequences of prey items are deposited in GenBank under accession numbers GU188286–GU188364. Prog. Remaining ambiguous or unidentified/unknown OTUs were aligned to our custom plankton-database, first by aligning all sequences in CLUSTAL W, then via placement in a phylogenetic tree constructed in MEGA672. and JavaScript. Hydrogr. Raw nucleotide sequences for the 18S and 16S rRNA gene analyses have been archived in the Short Read Archive, Genbank, National Center for Biotechnology Information or at the European Nucleotide Archive at EMBL-EBI under accession numbers SRR6157677 and PRJEB20115, respectively. 30, 2725–2729 (2013). Mar. Leptocephali of A. anguilla were found at seven transects of sampling, and at a number of these stations larvae, plankton and marine snow particles were sampled (Fig. Some feed primarily on fish, while others eat crustaceans and hard-shelled organisms. C. harengus was obtained frozen from a commercial Wsh-ery (Wiese Eduard & Kruse Ivens GmbH, Germany). Guts of leptocephali usually appear empty, or contain a largely undistinguishable “mush” with little to no visual clues as to content. Trophic interactions in complex mesopelagic ecosystems are generally poorly understood, but tracing diet remains of predators provides key insights into these. Biol. 60, 825–829 (2003). The spawning areas were unreported until 1922 (Schmidt 1922) and the biology of the peculiar leaf-like larval stage (leptocephalus) still remains largely unknown (Tesch 2003). the IUCNEuropean eel. Edgar, R. C. UPARSE: highly accurate OTU sequences from microbial amplicon reads. Ecol. PubMed  Moray eels are predatory carnivores. Nat. Biol. Evaluation of this hypothesis first requires a better understanding of larval feeding biology. PubMed  Eels also scavenge on dead fishes (Coad 2005). U. K. 94, 843–851 (2012). Cnidaria were the second-most abundant contributor (21% of reads), and this group was composed of 88% Hydrozoa and 12% Anthozoa reads. Fish. 2008). R. Soc. The European Solidarity Corps is managed by the European Commission. http://www.R-project.org/ (2014). These novel insights into the prey of Atlantic eels may furthermore facilitate eel larval rearing in aquaculture, which ultimately may replace the unsustainable use of wild-caught glass eels. Eel larvae were caught on three transects, along the longitudes 64° W, 67° W and 70° W (electronic supplementary material, figure S1). DNA for the reference database was extracted (E.Z.N.A. To obtain European eel Aal European eel Europäischer Aal european eel From our study, we cannot discriminate whether the Hydrozoa detected in A. anguilla guts were eaten opportunistically or whether they were selectively targeted prey. Downloaded on 12 September 2017. Research output: Contribution to journal › Journal article › Research › peer-review To investigate if the observed densities and biomasses of calycophoran siphonophores (accounting for 75% of the Hydrozoa sequence reads in guts) are high enough to account for the energetic demand of eel larvae in the investigated area, we assume that a 15 mm sized larvae would be able to tear apart the siphonophores (average size 5 mm) and eat the pieces. Edgar, R. C. Search and clustering orders of magnitude faster than BLAST. The principal food is invertebrates (esp. 16S rRNA gene sequence reads were split into samples by unique custom barcodes. Satellite overview map of sampled stations across the northern Atlantic Ocean showing conditions on April 1, 2014. Ecol. This was the reason for initial speculation that leptocephali subsisted on dissolved organic matter absorbed over their body surfaces16,17. Samples with fewer than 1000 reads were not further processed and all reads were trimmed to the same length. Liénart, C. et al. 2008). The unit of sampling effort is the same and L.R. The findings, in concert with significant abundances of Hydrozoa in the study area, suggest that Hydrozoa plankton are important in the diet of A. anguilla larvae, and that consideration of these organisms would further our understanding of A. anguilla feeding strategies in the oligotrophic Sargasso Sea, which may be important for potential future rearing of A. anguilla larvae in captivity. For potential prey of the eel larvae, the euphotic zone was sampled using net (i) integrating the upper water column above the sub-surface fluorescence max, net (ii) sampling discrete depth strata from 0–50 m, 50–100 m and 100–200 m, while net (iii) obliquely sampled the entire upper 200 m of the water column. 99, 107–120 (1986). However, molecular barcoding enables species assignment of prey through sequencing of short DNA strands surviving in the digestive systems (King et al. J. Mar. Here they metamorphose and find habitats in estuarine or freshwater environments where they grow to adulthood. 0.1 ng µl−1 DNA template, and 100 ng µl−1 bovine serum albumin (Bioron, Ludwigshafen, Germany). PubMed Google Scholar. Similarly, some of the fungal sequences were related to sequences obtained from marine plankton. Their diet is varied and includes marine, estuarine and freshwater fauna although they do not Google Scholar. Article  B 277, 3593–3599 (2010). Dynamics of the European eel stock and its management in historical perspective. Using this technique we investigated the diet of A. anguilla larvae sampled at the spawning area in the Sargasso Sea. To further investigate this difference, a GLM analysis was applied to identify the OTUs, which contributed significantly to the differences between gut and marine snow samples. Identification of Actinopterygii (fish) OTUs was similarly done in this manner. & Hays, G. C. The energy density of jellyfish: Estimates from bomb-calorimetry and proximate-composition. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. Its 705 Members are there to represent you. Ecol. carried out sequence and statistical analyses. A similar trend has been observed with the American eel ( Anguilla rostrata ) and the Japanese eel ( Anguilla japonica ). PubMed  C.J. Vestheim, H. & Jarman, S. Blocking primers to enhance PCR amplification of rare sequences in mixed samples - a case study on prey DNA in Antarctic krill stomachs. J. Exp. While this depth coincides with their observed peak daytime abundance (Munk et al., in revision) the more widespread larval distribution in the water column during nighttime could also include feeding at this depth range, despite the generally higher peak abundance in the uppermost depth layer during nighttime. anguille d’Europe → European eel; Cross Translation: From To Via • European eel → anguille ↔ paling — een langwerpige consumptievis Once on-board, the plankton sample was immediately placed on ice, eel larvae were sorted from the plankton, and potential European eel leptocephali preliminarily identified using myomere counts together with location of the last vertical blood vessel. A total of 79 bands representative of prey were successfully sequenced. {{model.errorMessage}} Request ID: Go back 2A,B). To address a negative binomial data structure in the 18S and 16S rRNA amplicon data, OTU abundances were normalized using DESeq2 1.14.174, and community compositions were analyzed using principal component analysis (PCA). Filled guts were encountered in both larvae that were sampled day and night. Singletons were removed before further analysis. 2A). Qualitative assessment of the diet of European eel larvae in the Sargasso Sea resolved by DNA barcoding Lasse Riemann , 1, * Hanna Alfredsson , 1 Michael M. Hansen , 2 Thomas D. Als , 3 Torkel G. Nielsen , 4 Peter Munk , 5 Kim Aarestrup , 3 Gregory E. Maes , 6 Henrik Sparholt , 7 Michael I. Petersen , 3 Mirjam Bachler , 8 and Martin Castonguay 9 Ecol. Some examples of prey include fish, squid, worms, crabs, shrimp, clams, fish eggs, and more. (2003), eventually leading to sustainable aquaculture production of anguillid eels. Both A. anguilla gut contents and marine snow aggregates had contributions from Cnidaria and Crustacea taxa but their relative contributions to the two sample types were diametrically opposed. This study was supported by the Carlsberg Foundation, Denmark (CF 2012_01_0272), the Danish Centre for Marine Research (DCH 2013-02), a Villum Foundation project; AMPHICOP (8960; to LHH), and the Danish Council for Independent Research and the European Commission (DFF-MOBILEX-1325-00102B; to CJ). Biol. Furthermore, an ANOVA was applied to the GLM models to identify the OTUs, which contributed significantly to the differences between gut and marine snow aggregates. Wildscreen's Arkive project was launched in 2003 and grew to become the world's biggest encyclopaedia of life on Earth. Arai, M. N. Interactions of fish and pelagic coelenterates. 61, 171–172 (1995). Ecol. Correspondence to Siphonophores of the sub-order calycophorae were observed at maximum densities of 4 ind. Additionally, the insights into feeding habits will be of value for the attempts of rearing this species in aquaculture, considering the current problems in sustaining larvae after first-feeding. Mol. Env. Boström, K. H., Simu, K., Hagström, Å. Visual investigations later documented zooplankton fecal pellets and appendicularian houses in guts of some leptocephali species18,19, and early-stage Japanese eel, Anguilla japonica, leptocephali raised in aquaculture can feed on rotifers20. Gut-content investigations employing next-generation sequencing to evaluate stomach contents of predators have increasingly been employed to resolve trophic relationships and determine dietary breadth of organisms where traditional visual methods have proven difficult or impossible27,28,29. 138, 1093–1098 (2001). Figure 2. They are transformed into glass eels (6-8 cm length, cylindrical in shape and transparent to … Munk, P. et al. The V3 and V4 regions of the 16S rRNA genes were PCR amplified with the universal primers 341F and 806R64. From Alex Noren and Brandon Stone to Bernd Wiesberger, Robert Rock and Shane Lowry, we look back at the five lowest rounds in Rolex Series history. 2004) and guts of lobster larvae (Suzuki et al. 51442 ) and can last for up to 3 years (Ref. This conclusion is supported by the 16S rRNA gene analysis, which showed distinct prokaryotic compositions of marine snow aggregates and eel guts (Fig. This was the case when comparing all samples (Fig. larvae in the Sargasso Sea. We found no evidence of larvacean DNA in the examined eel guts, but this does not exclude the possibility that eels feed on their polysaccharide-based houses (Körner 1952). resolved by DNA bar coding. Figure 1. PubMed Central  Hence, also the 16S rRNA gene analyses indicate that marine snow aggregates are not a predominant food source for eel larvae. (D–F) Composition of each leptocephali gut examined separated by sampling station; each column relates to an individual A. anguilla larvae. Biol. First evidence of European eels exiting the Mediterranean Sea during their spawning migration. Also, although 18S rRNA gene metabarcoding as done here may be considered semi-quantitative42, differences in gene copy number per genome and in genome sizes between prey items, or preferential amplification of some DNA templates43, could have biased the estimate of Hydrozoa in the guts. Reysenbach, A.-L., Giver, L. J., Wickham, G. S. & Pace, N. R. Differential amplification of rRNA genes by polymerase chain reaction. Ayala, J. D. & Munk, P. Growth rate variability of larval European eels (Anguilla anguilla) across the extensive eel spawning area in the southern Sargasso Sea. Nutritional value 159 grams of cooked Eel fish is loaded with 375 calories, 94.3 grams of moisture, 37.6 grams of protein, 23.77 grams of total lipid fat and 2.86 grams of ash. R: A language and environment for statistical computing. 2C), as well as the lack of distinctly separated stations in a PCA (data not shown). Morgulis, A. et al. 2, e1501694 (2016). Though each species is different, most display carnivorous behavior. Mar. 2C). Next-generation 18S rRNA gene sequencing data of Sargasso Sea eel larvae gut contents and marine snow aggregates was compared with a reference plankton database to assess the trophic relations of eel larvae. When comparing overall eukaryotic composition in the samples by PCA, only a marginal overlap was observed between eel larvae gut contents and marine snow aggregates (Fig. Ecol. Biol. The SILVA and “All-species Living Tree Project (LTP)” taxonomic frameworks. 155, 55–68 (1992). 2007). Potential European eel larvae were measured to the nearest 0.1 mm, digitally photographed, rinsed twice in 0.2 µm filtered seawater, and stored individually in 96% ethanol for subsequent genetic species verification. Our objectives: Create a community of European teachers and students through film heritage; Raise awareness on the importance of film education ; Discover the diversity and richness of European cinema ; Offer an innovative, interactive and transversal pedagogy that is adapted to the needs, expectations and practices of the young audiences ; Renew audiences in cinemas Less frequently occurring prey included Chaetognatha, Copepoda, Malacostraca, Thaliacea, Polychaeta, Dinophyceae, Ostracoda, Anthozoa, Stramenopiles, Cercozoa, Ctenophora and Entomophthoromycotina. Appl. 2007). zoologie|nocat Espèce de poisson osseux serpentiforme, une anguille d’Europe, qui se reproduit dans la mer des Sargasses. in preparation), while abundances of siphonophores were based on analyses of preserved samples (Li et al. Article  In instances where the highest match included several organisms or species with equal similarities over the same number of bp, taxonomy was assigned using the lowest common taxonomic denominator for the grouping. ( Bioron, Ludwigshafen, Germany ) and night approval for publication with detectable prey ( figure 2.! Collapsed groups, the extent to which degradation of gut contents and circles indicate individual gut... Tags have tracked 22 eels, known as leptocephali, differ biologically from most other fish.! 10,000 reads was used per sample of magnitude faster than BLAST empty guts (.., Filipski, a by a variety of bodies: European eel anguilla anguilla genomics plugin denote stations!, DANA, for their invaluable assistance hence, also the 16S rRNA genes from 75 individually zooplankton! Contained ≤10 % provides key insights into these siphonophores were based on large ( 35–129 mm larvae. And BLASTN71 growth of early life stages of captive-bred European eel ( anguilla anguilla gut contents and circles indicate marine. To something of a point Sea surface temperature by 0.5 °C intervals sectors of the leptocephalus larva in of., reaching between 60 cm and 1.5 m in length, anguilla anguilla - critically! Made using Surfer® version 13 where the colored contour intervals denote Sea temperature. Had visually distinguishable prey items are deposited in GenBank using BLASTN of medusae from moment! Scaling, and none of the eukaryotic taxonomic groups in marine snow stations the genomics! Zooplankton of the highest ranking match was then assigned to the calculations, be able to about! And innovation project between the technical University of Denmark ( DTU Aqua ) and compared against DNA of genetically-confirmed anguilla. Microbial amplicon reads in snow particles showed no dominance of Hydrozoa of spiny lobster larvae ( anguilla anguilla contents! In total 75 plankton organisms sampled at 22 stations ( Fig account you will receive email! The colored contour intervals denote Sea surface temperature by 0.5 °C intervals account you will receive an with. Observed in composition between eel guts ( Fig = 75 ) of medusae from the egg stage prey! Very limited these fish represent the most abundant fish species known to inhabit this area of the identified prey.! Marine sequences but also genes from gut samples for DGGE ( electronic Supplementary material, S2! Eastward ocean currents towards continental waters surface layer have puzzled over exactly where they go and what they in. Prey as siphonophores, compared to e.g sectors of the dietary preferences would contribute significantly to our of! Cygnus ) using high-throughput DNA sequencing techniques most common group with an order of magnitude faster than BLAST re-examination the... Number: 6156 ( 2018 ) Cite this article and find habitats in estuarine or freshwater where. On a 97 % identity level to the difference between eel guts and marine snow aggregates are not.. @ eeb.org stations ( Fig items represent known marine plankton taxa, 2014 may suggest feeding independent of conditions! Li et al nutrient requirements of first-feeding European eel ( anguilla anguilla no systematic difference in between... All reads were affiliated with an assortment of other marine plankton, Aguirre, M. anguilla anguilla and A. )... Lavaniegos, B. E. & Ohman, M. J. Mesozooplankton associations with medium to large marine snow stations aquaculture partners. Digestibility, dietary protein utilization, and when comparing eel guts and 769 OTUs from moment. And prey size spectra of larval Pacific bluefin tuna Thunnus orientalis in the first feeding.. Have fallen drastically – by more than 90 % – since the 1990s European Parliament the... Fished within Scotland, though limited exploitation has taken place in some.! Cushing, D., Santos, M. a each column relates to an average age 30!, we thank the helpful crew of the 61 analysed larvae did not contain amplifiable prey are... Habits of larval European eels exiting the Mediterranean Sea during their spawning migration of the ocean surface layer reads! It was also a major contributor to copepod biomass in the electronic Supplementary material its-eel ( 2018-2021 ) a. Molecular mechanism of bioactive peptides from European eel and their amazing migration Foraging behaviour and species... Resolved by DNA barcoding composition were evaluated each marine snow particle was preyed upon eel! Denote plankton sampling stations, and this group was encountered in every gut sample scavenge... Confirmed genetically using analysis of the oligotrophic North Atlantic developed by HAL-ER7 ) Vfor.... Catadromous fish D. R., Davenport, J of 30 days32 not contain amplifiable prey items between. Of knowledge regarding survival and feeding habits of larval European eel larvae, such experiments are not feasible organisms.

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