Search

Many anguillid eel species display facultative catadromy. Some eel spend their entire life cycle in marine coastal areas, but the geographical extent of this, especially at the extremes of their distributional ranges, is unknown. We analysed otolith Sr:Ca and Ba:Ca from yellow-stage European eel (Anguilla anguilla) sampled along the coast of Norway and in several freshwater lakes (58[degrees]N-63[degrees]N), to infer their initial settlement and later life movement patterns with regards to habitat salinity. Most eel (80%) sampled in marine habitats (n = 371) had settled and remained in marine water, but 20% had moved between marine and freshwater habitats and were hence classified as inter-habitat shifters. Among freshwater sampled eel (n = 99), 80% had settled and remained in fresh water, but 20% were classified as inter-habitat shifters. The average growth rates for marine water residents, inter-habitat shifters, and freshwater residents were 35, 27, and 17 mm * [year.sup.-1], respectively. Northern European shallow marine habitats may serve as important yellow eel growth habitats and may be critical to buffer the European eel population against the general decrease in continental recruitment. Key words: otolith microchemistry, anguillids, Anguilla anguilla, salinity, age, growth rate, 1. Introduction The decline of the panmictic European eel (Anguilla anguilla) population is well documented (Drouineau et al. 2018; ICES 2020). The data used to support this apparent decline have [...]

Societal Impact Statement: New sources of essential and other nutritionally and/or pharmacologically important fatty acids for human use can be discovered through bioprospecting. Demonstrating how fatty acids in plants and algae are distributed across a phylogeny is a critical first step in this process. Here, new sources of essential omega‐3 fatty acids that are critically important to human health were identified, such as green and Chromista algae, bryophytes and some angiosperm families. The identification of certain taxa that are high in critical fatty acids is important for developing new sources of these healthful compounds. Summary: Essential fatty acids (EFA) including long‐chain omega‐3 and omega‐6 EFA are key nutrients that broadly support the health of individuals and the ecosystems they inhabit. Production of these EFA is critical to global nutritional security, and therefore, it is imperative to assess the distribution patterns of FA in plants to bioprospect new resources that do not threaten biodiversity.We used a meta‐analytic approach (phylogenetic signal analysis), which incorporated a wide variety of taxa to map FA profiles including both presence and abundance of specific FA and EFA onto a plant phylogeny including algae, bryophytes, pteridophytes, gymnosperms and angiosperms.Our phylogenetic signal analysis revealed that presence/absence of most FA of interest were randomly or ubiquitously distributed, while FA content was significantly clustered in specific clades for most key FA (including eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and nervonic acid). Both green and Chromista algae displayed relatively high proportions of EPA and DHA, while green algae contained higher proportional amounts of stearidonic acid (SDA). Further, signal analysis revealed high proportional content of gamma‐linoleic acid (GLA) in bryophytes and some angiosperm families, suggesting potential sources for bioprospecting GLA.This analysis provides a crucial foundation for understanding the influence of phylogenetic relationships in the relative proportions of key FA in plants and algae across a diverse phylogeny. Furthermore, in demonstrating how fatty acids in plants and algae are distributed across a phylogeny, we provide a critical first step in bioprospecting for new sources of essential and other nutritionally‐ and/or pharmacologically important fatty acids for human use. [ABSTRACT FROM AUTHOR]

We combined fatty acid (FA) and stable isotope (SI) analyses to investigate the trophic ecology of different stages of European eels (Anguilla anguilla) across seawater (SW), brackish water (BW), and freshwater (FW) habitats. Salinity was the main driver of differences in the biochemical composition, and the greatest variation occurred between SW and FW eels. SW eels had a higher content of the FA indicator of carnivory, as well as the highest stable isotope ratios (C, N). In contrast, FW eels exhibited the highest lipid content and omega-6 polyunsaturated FA, but the lowest stable isotope ratios, suggesting major dietary differences between the eels in these two habitats. While the biochemical composition of BW eels was closer to those of SW eels, BW eels had the largest SI range, indicating higher dietary plasticity. FW individuals had better overall condition compared to SW eels. Independent of habitat, larger individuals were in the best condition, and had higher lipid content and monounsaturated FA. These findings suggest a biological advantage for eels to maintain a catadromous life history strategy. Nous avons combine des analyses d'acides gras (AG) et d'isotopes stables (IS) afin d'etudier l'ecologie trophique d'anguilles europeennes (Anguilla anguilla) a differentes etapes de leur cycle biologique dans des habitats d'eau de mer (EM), d'eau saumatre (ES) et d'eau douce (ED). La salinite s'avere la principale cause des variations de composition biochimique, et les plus grandes differences sont observees entre les anguilles d'EM et d'ED. Les anguilles d'EM presentent une plus grande concentration de l'AG indicateur de la carnivorie, ainsi que les rapports d'isotopes stables (C, N) les plus eleves. En comparaison, les anguilles d'ED presentent la plus forte teneur en lipides et en AG polyinsature omega-6, mais les rapports d'isotopes stables les plus faibles, ce qui indiquerait des differences majeures des regimes alimentaires des anguilles vivant dans ces deux habitats. Si la composition biochimique des anguilles d'ES est plus proche de celle des anguilles d'EM, les anguilles d'ES presentent la plus grande fourchette d'IS, ce qui indique une plus grande plasticite de leur regime alimentaire. Les specimens d'ED presentent un meilleur embonpoint global que les anguilles d'EM. Independamment de l'habitat, les specimens plus grands presentent le meilleur embonpoint et ont les plus hautes teneurs en lipides et en AG monoinsatures. Ces constatations donnent a penser que le maintien d'une strategie de cycle biologique catadrome offre un avantage biologique aux anguilles. [Traduit par la Redaction], Introduction The European eel (Anguilla anguilla) is a facultatively catadromous species (Tzeng et al. 2000; Daverat et al. 2006). Adult eels reproduce and spawn in the Sargasso Sea. From there, [...]

Abstract: Polyunsaturated fatty acids (PUFA), especially long-chain (i.e., [greater than or equal to]20 carbons) polyunsaturated fatty acids (LC-PUFA), are fundamental to the health and survival of marine and terrestrial organisms. [...]

Long-chain polyunsaturated fatty acids (LC-PUFA) are critical for the health of aquatic and terrestrial organisms; therefore, understanding the production, distribution, and abundance of these compounds is imperative. Although the dynamics of LC-PUFA production and distribution in aquatic environments has been well documented, a systematic and comprehensive comparison to LC-PUFA in terrestrial environments has not been rigorously investigated. Here we use a data synthesis approach to compare and contrast fatty acid profiles of 369 aquatic and terrestrial organisms. Habitat and trophic level were interacting factors that determined the proportion of individual omega-3 (n-3) or omega-6 (n-6) PUFA in aquatic and terrestrial organisms. Higher total n-3 content compared with n-6 PUFA and a strong prevalence of the n-3 PUFA eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) characterized aquatic versus terrestrial organisms. Conversely, terrestrial organisms had higher linoleic acid (LNA) and alpha-linolenic acid (ALA) contents than aquatic organisms; however, the ratio of ALA:LNA was higher in aquatic organisms. The EPA + DHA content was higher in aquatic animals than terrestrial organisms, and increased from algae to invertebrates to vertebrates in the aquatic environment. An analysis of covariance (ANCOVA) revealed that fatty acid composition was highly dependent on the interaction between habitat and trophic level. We conclude that freshwater ecosystems provide an essential service through the production of n-3 LC-PUFA that are required to maintain the health of terrestrial organisms including humans. Key words: aquatic ecosystems, conservation, eicosapentaenoic acid, docosahexaenoic acid, food webs. Les acides gras polyinsatures a longues chaines (LC-PUFA) sont critiques pour la sante des organismes aquatiques et terrestres, consequemment, la comprehension de la production, de la distribution et de l'abondance de ces composes merite une grande attention. Bien que la dynamique de la production et de la distribution des LC-PUFA dans les milieux aquatiques ait ete bien documentee, on n'a pas effectue rigoureusement et de facon systematique et integree une comparaison avec les LC- PUFA dans les milieux terrestres. Les auteurs utilisent ici une synthese de donnees pour comparer et contraster les profils des acides gras chez 369 organismes aquatiques et terrestres. L'habitat et le niveau trophique ressortent comme facteurs interactifs determinant la proportion des omegas-3 (n-3) ou des omegas-6 (n-6) individuels, entre les organismes aquatiques et terrestres. Une teneur totale plus elevee des PUFA n-3 comparativement aux n-6, et une forte prevalence des PUFA n-3 en acide eicosapentaenoique (EPA) et docosahexaeonique (DHA) caracterisent les organismes aquatiques contre terrestres. Reciproquement, les organismes terrestres montrent une plus forte teneur en acide linoleique (LNA) et alpha-linolenique (ALA) que les organismes aquatiques; cependant, le rapport ALA:LNA est plus eleve chez les organismes aquatiques. La teneur en EPA+DHA est plus elevee chez les animaux aquatiques que les animaux terrestres et augmente en passant des algues, aux invertebres et aux vertebres, en milieu aquatique. Une analyse en covariance revele que la composition en acides gras depend fortement de l'interaction entre l'habitat et le niveau trophique. On conclut que les ecosystemes d'eau douce fournissent un service essentiel par la production des LC-PUFA n-3 necessaires pour maintenir la sante les organismes terrestres incluant l'homme. [Traduit par la Redaction] Mots-cles: ecosystemes aquatiques, conservation, acide eicosapentaenoique, acide docosahexaeonique, chaine alimentaire., Introduction Long-chain (i.e., ≥ 20 carbons long) polyunsaturated fatty acids (LC-PUFA) are critically involved with key physiological functions of aquatic and terrestrial vertebrates, including humans, in supporting brain function, cardiovascular [...]

Calanus finmarchicus were reared from eggs to adults at 12°C and 16°C with non‐limiting food in combination with ambient (600 μatm) and high (1100 μatm) pCO2. These conditions are likely to be encountered by the species at the southern margins of its biogeographical range by the end of the century. Dry weight (DW), carbon (C) and nitrogen (N) mass, oil‐sac volume (OSV), fatty acid composition (FA), and oxygen consumption rates (OCR) were measured on newly molted stage CV copepodites and recently molted adult females. By focusing our measurements on these precise events in the life cycle, we were able to obtain a more accurate comparison of growth and respiration across treatments. Copepods raised at 12°C had a significantly greater DW, OSV, and C and N mass than those raised at 16°C High pCO2, independent of temperature, was associated with a further increase in the DW and C content of the copepods. Interactive effects of temperature and pCO2 resulted in a larger OSV at low temperature and high pCO2. Mass‐specific respiration rates were significantly lower at lower temperatures and elevated pCO2 suggesting that the increase in mass (DW, C, and OSV) resulted from reduced metabolic cost. The composition of fatty acids in the copepods varied mainly with temperature. Two fatty acids varied with pCO2: 16:0 tended to decrease with higher pCO2 and 18:3n−3 tended to increase with higher pCO2. These observations suggest that elevated pCO2/lower pH in future oceans may have a beneficial effect on C. finmarchicus. [ABSTRACT FROM AUTHOR]

Recent food-web changes in the Laurentian Great Lakes are affecting energy and nutrient allocation to lake whitefish (Coregonus clupeaformis) with potential downstream effects on egg condition and recruitment. We tested whether egg condition was conserved or varied with maternal condition in eight stocks from Lakes Erie, Michigan, and Superior. Egg condition was conserved across stocks based on (i) a lack of correlation between females and eggs for total lipid, DHA, and other essential fatty acids; (ii) higher levels of energy and long-chain polyunsaturated fatty acids (LC-PUFA) in eggs compared with females; and (iii) no among-stock differences for those same variables in eggs. Females from northern Lake Michigan generally made the greatest trade-offs between egg size and fecundity. Highly fecund females provisioned less lipid, but more n-3 LC-PUFA to their eggs. A lack of stock-level patterns in energy and nutrient allocation suggests that trade-offs occur at the level of individual females and that females in poor condition make greater trade-offs among egg size and fecundity, total lipids, and n-3 LC-PUFA than females in good condition. Resume: Des modifications recentes des reseaux trophiques dans les Grands Lacs laurentiens ont une incidence sur l'allocation d'energie et de nutriments chez les grands coregones (Coregonus clupeaformis), incluant des effets en aval potentiels sur l'etat des reufs et le recrutement. Nous avons tente d'etablir si l'etat des reufs etait conserve ou variait selon l'etat d'embonpoint maternel au sein de huit stocks des lacs Erie, Michigan et Superieur. L'etat des reufs etait conserve dans tous les stocks a la lumiere (i) de l'absence de correlation entre les femelles et les reufs sur le plan des lipides totaux, de l'ADH et d'autres acides gras essentiels, (ii) de niveaux plus eleves d'energie et d'acides gras polyinsatures a longue chaine (AGPLC) dans les reufs que chez les femelles et (iii) de l'absence de variation au sein des stocks en ce qui concerne ces memes variables dans les reufs. Les femelles de la partie nord du lac Michigan sont celles qui presentaient les compromis les plus importants entre la taille des reufs et la fecondite. Les femelles tres fecondes transferaient moins de lipides, mais plus d'AGPLC n-3 a leurs reufs. L'absence de tendance en matiere d'allocation d'energie et de nutriments a l'echelle des stocks donne a penser que les compromis s'exercent a l'echelle individuelle chez les femelles et que les femelles en mauvais etat d'embonpoint font de plus grands compromis entre la taille des reufs et la fecondite, les lipides totaux et les AGPLC n-3 que les femelles en bon etat. [Traduit par la Redaction], Introduction Lake whitefish (Coregonus clupeaformis) support important commercial, recreational, and aboriginal subsistence fisheries throughout the Laurentian Great Lakes. From 1995 to 2005, lake whitefish growth and body condition declined precipitously [...]