Description of a new moray eel (Anguilliformes: Muraenidae) from the Philippines, with a preliminary assessment of genetic and morphological variations of the Uropterygius concolor species complex.

Uropterygius concolor Rüppell, the type species of the genus Uropterygius, is a small, uniformly brown moray considered to be widely distributed in the Indo-Pacific region. However, a recent study indicated that the real U. concolor is currently known only from the type locality in the Red Sea, and species recorded outside the Red Sea may represent a species complex that comprises several species. In this study, we assess the genetic and morphological variations of this species complex based on available data. Analyses of cytochrome c oxidase subunit I sequences revealed at least six distinct genetic lineages recognized under 'U. concolor'. After carefully comparing the morphologies, one of the lineages is described herein as a new species, Uropterygius mactanensis sp. nov., based on 21 specimens collected from Mactan Island, Cebu, Philippines. Another distinct lineage is considered to be a possibly undescribed species based on diagnostic morphological characters. Although the taxonomic status of junior synonyms of U. concolor and some lineages still remain unresolved, this study provides informative morphological characters (i.e., tail length, trunk length, vertebrae number, and arrangement of teeth) that can be used in future studies on this species complex.

Prioritization based on risk assessment to study the bioconcentration and biotransformation of pharmaceuticals in glass eels (Anguilla anguilla) from the Adour estuary (Basque Country, France).

The presence of contaminants of emerging concern in the aquatic environment directly impacts water-living organisms and can alter their living functions. These compounds are often metabolized and excreted, but they can also be accumulated and spread through the food chain. The metabolized contaminants can also lead to the formation of new compounds with unknown toxicity and bioaccumulation potential. In this work, we have studied the occurrence, bioconcentration, and biotransformation of CECs in glass eels (Anguilla anguilla) using UHPLC-HRMS. To select the target CECs, we first carried out an environmental risk assessment of the WWTP effluent that releases directly into the Adour estuary (Bayonne, Basque Country, France). The risk quotients of every detected contaminant were calculated and three ecotoxicologically relevant contaminants were chosen to perform the exposure experiment: propranolol, diazepam, and irbesartan. An experiment of 14 days consisting of 7 days of exposure and 7 days of depuration was carried out to measure the bioconcentration of the chosen compounds. The quantitative results of the concentrations in glass eel showed that diazepam and irbesartan reached BCF ≈10 on day 7, but both compounds were eliminated after 7 days of depuration. On the other hand, propranolol's concentration remains constant all along with the experiment, and its presence can be detected even in the non-exposed control group, which might suggest environmental contamination. Two additional suspect screening strategies were used to identify metabolization products of the target compounds and other xenobiotics already present in wild glass eels. Only one metabolite was identified, nordiazepam, a well-known diazepam metabolite, probably due to the low metabolic rate of glass eels at this stage. The xenobiotic screening confirmed the presence of more xenobiotics in wild glass eels, prominent among them, the pharmaceuticals exemestane, primidone, iloprost, and norethandrolone.

Evaluating the impact of hydropower on downstream migrating anguillid eels: Catchment-wide and fine-scale approaches to identify cost-effective solutions.

Hydropower is an increasingly popular source of renewable and 'green' (in terms of emissions) energy, but reduced longitudinal connectivity and diverting flow through turbines can have negative impacts on catadromous anguillid eel species that have declined globally. There is an urgent need for environmental managers to perform remediation actions, such as protecting flows for migratory fish and providing passage solutions at infrastructure, under increasing legislative pressure. To deliver this, a more comprehensive understanding of eel migration in catchments with hydropower is required. Here, we illustrate the importance of catchment-wide and fine-scale acoustic telemetry, coupled with the influence of eel maturation (i.e. sex steroid levels), to determine the impact of Wairua run-of-river Power Station (WPS) on downstream migrating shortfin eels (Anguilla australis; n = 25) in Wairua River, New Zealand. Migration speed through the unregulated reach upstream of WPS was positively correlated with flow, but not eel length or sex steroids. Three eels passed a diversion weir (DW) to follow the natural watercourse and eight entered the WPS canal. Eels predominantly entered (95.2%) and were last detected (85.7%) in WPS forebay during hours of darkness. Eleven (52%) of the 21 eels that entered WPS forebay were impinged or entrained, all when three or four turbines were in operation (power generation >3.04 MW). Ten (48%) passed WPS spillway during significantly higher spill than impinged or entrained eels, with four passing during no turbine operation, after experiencing high flows near the intake (multiple receivers in WPS forebay used to quantify fine-scale behaviour). On average, eels were impinged or entrained at WPS significantly quicker (6.40 ± 11.13 days) than eels that entered the spillway (25.17 ± 15.12 days), but eel length and sex steroids did not significantly influence fate. Of the eels that migrated through the entire 55 km study reach, passage time at DW and WPS equated to 0.01-0.02% and 47.62-92.17% of their migration, respectively. Mitigation for WPS (and similar power schemes) should focus on operational or physical changes at DW to minimise eels entering power station forebay(s). Turbine shutdowns, ensuring WPS spillway is available and the provision of a bypass channel in WPS forebay are also discussed as ways to conserve the species with the potential to save costs for water resource managers.

Assessment of the quality of European silver eels and tentative approach to trace the origin of contaminants - A European overview.

The European eel is critically endangered. Although the quality of silver eels is essential for their reproduction, little is known about the effects of multiple contaminants on the spawning migration and the European eel management plan does not take this into account. To address this knowledge gap, we sampled 482 silver eels from 12 catchments across Europe and developed methods to assess three aspects of eel quality: muscular lipid content (N = 169 eels), infection with Anguillicola crassus (N = 482), and contamination by persistent organic pollutants (POPs, N = 169) and trace elements (TEs, N = 75). We developed a standardized eel quality risks index (EQR) using these aspects for the subsample of 75 female eels. Among 169 eels, 33% seem to have enough muscular lipids content to reach the Sargasso Sea to reproduce. Among 482 silver eels, 93% were infected by A. crassus at least once during their lifetime. All contaminants were above the limit of quantification, except the 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), Ag and V. The contamination by POPs was heterogeneous between catchments while TEs were relatively homogeneous, suggesting a multi-scale adaptation of management plans. The EQR revealed that eels from Warwickshire were most impacted by brominated flame-retardants and agricultural contaminants, those from Scheldt were most impacted by agricultural and construction activities, PCBs, coal burning, and land use, while Frémur eels were best characterized by lower lipid contents and high parasitic and BTBPE levels. There was a positive correlation between EQR and a human footprint index highlighting the capacity of silver eels for biomonitoring human activities and the potential impact on the suitability of the aquatic environment for eel population health. EQR therefore represents a step forward in the standardization and mapping of eel quality risks, which will help identify priorities and strategies for restocking freshwater ecosystems.

An inspection-based assessment of obstacles to salmon, trout, eel and lamprey migration and river channel connectivity in Ireland.

Knowledge of the location, physical attributes and impacts of obstacles on river connectivity is a requirement for any mitigating action aimed at restoring the connectivity of a river system. Here, we present a study that recorded the numbers and physical diversity of obstacles in 10 river catchments in Ireland, together with the impact these structures had on overall river connectivity. A total of 372 obstacles were recorded, 3 of these were dams, and the remainder were low-head weirs/sluices, obstacles associated with road or rail crossings of rivers and natural structures. The degree of fragmentation was estimated in each catchment by calculating obstacle density and the Dendritic Connectivity Index (DCI). DCI scores were calculated for 4 native Irish fish species with different life-histories, namely diadromous (Atlantic salmon, sea trout, European eel, sea lamprey) and potamodromous (brown trout). Obstacle density ranged between 1.2 and 0.02 obstacles/km of river. Six of the 10 catchments had at least one obstacle located on the mainstem river at least 5 km from its mouth/confluence. These 6 catchments typically had the lowest connectivity scores for diadromous species and ranged between 0.6 and 44.1 (a fully connected river would receive a maximum score of 100). While there was no significant correlation between obstacle density and the DCI score for diadromous fish, a significant negative correlation was detected between obstacle density and the DCI score for potamodromous brown trout. Here, we highlight the merit of these obstacle assessments and associated challenges for decision-making relating to prioritisation of obstacles for removal or modification.

Faces, Voices and Places in Anguilla / Rostros, Voces y Lugares en Anguila

Anguilla is a small, picturesque island in the Eastern Caribbean, the most northerly of the Leeward Islands. Its capital is The Valley. Although it is a British Overseas Territory, the island is home to approximately fifteen thousand people, each with its own unique culture and way of living. Anguilla has become a high-end tourist destination because of its breathtaking beaches and scenery, Anguilla has become a high-end tourist destination. In fact, tourism and tourism-related construction have become the main contributors to the country’s Gross Domestic Product (GDP). Thus, Anguilla enjoys relatively high levels of health and well-being. Demonstrating this is the island’s increasing life expectancy and decreasing death rate. However, a rise in chronic, non-communicable diseases is a cause for concern; this increase is primarily due to drastic lifestyle changes. Vulnerable groups identified by the government include children, the elderly, the disabled, adolescent boys (particularly those who do not complete secondary school) and young single mothers.

Biofilter treatment of aquaculture water for reuse applications.

Biotreatment of aquaculture water for recirculation purposes is a sensible mean to support the further growth of aquaculture industry without excessive water demands that are environmentally unsustainable. This study evaluates the efficacy of biofilter treatment of an eel (Anguilla japonica) culture pond water using different filter media and flow scheme arrangements. The experimental results demonstrate that biofilter systems packed with suitable filter media are capable of improving the quality of effluents for recirculation applications. The characteristics of the filter media appear to be more critical than biofilter flow scheme arrangements in affecting the efficacy of the biofilter treatment. Filter media with surface and structural characteristics are conducive to the development of biofilms and the capture of organic suspended matter are desirable to ensure good and consistent biofilter performance. Under such circumstances the bacterial "consortia" in the biofilter are capable of utilizing the captured organic suspended matter as an alternative substrate to support their metabolic activities when the concentration of the primary substrate (i.e., BOD) is low. For the eel pond water, a biofilter packed with filter media having cross-link structures and a high bed porosity, followed by another biofilter packed with a type of filter media having rough surfaces, produced the best results under the conditions tested. Moreover, a preliminary cost-benefit analysis confirms its cost advantages.

Meeting energy budgets by modulation of behaviour and physiology in the eel (Anguilla anguilla L.).

Availability of energy for feeding, and the scope to accommodate the associated increase in oxygen demand (SDA: specific dynamic action) can, to a large degree, regulate the future feeding and energy availability of an animal. There is a fundamental conflict between locomotion and SDA within the physiological capacity of a mobile organism to respire sufficiently in order to simultaneously meet both requirements. This paper is a first attempt to integrate the costs of behaviour and physiology and produce a testable model of energy allocation in the eel. Total oxygen consumption (metabolic rate MO2) of the eel (Anguilla anguilla L.) was 109 micromol O2 x g(-1) x day(-1) with a cost of measured protein synthesis representing 49% of this value, and measured routine swimming (locomotor) activity representing approximately 34%. By allocating periods of reduced activity, the eel is able to develop a strategy to prudently meet the costs of feeding and temporally balance energy budgets (in terms of oxygen) by modulation of the behaviour and demands of physiology.

Assessment of inner dynein arm structure and possible function in ciliary and flagellar axonemes.

The construction and assessment of a three-dimensional computer-generated model of inner dynein arms on a 96-nm repeat unit of an axonemal doublet is described. The model is based on published electron micrographs of axonemes from Tetrahymena cilia and eel sperm, which were prepared using several different techniques: negative stain, freeze etch, and thin section. The inner arm structure is represented as three inner dynein arm complexes containing four inner dynein arms (IDAs), three dyads, and one single-headed arm, each capable of bridging the interdoublet gap. The IDA structures in the model have been correlated with the domains containing dynein heavy-chain isoforms mapped by several authors using genetic analyses of Chlamydomonas mutants. The model is consistent with micrographic evidence from axonemes of cilia and flagella from other organisms that led previously to conflicting structural interpretations. In this reconciling interpretation, the different alignments of the IDAs relative to the corresponding outer dynein arms observed in micrographs of differently prepared samples, result from the IDAs being arrested at different stages of their cycles of activity in each preparation. By interpolating between these positions of arrest, cycles of activity are proposed for each of the IDAs during which the arms attach to the neighbouring doublet microtubule and drive it tipwards.

Cognitive antecedents of consumers' willingness to purchase fish rich in polyunsaturated fatty acids (PUFA).

A sample of UK consumers (N = 311) was interviewed in order to identify the attitudinal, cognitive and involvement characteristics of probable early adopters of polyunsaturated fatty acid (PUFA) fed fish. Attitude to fish significantly influenced PUFA fish, premium price PUFA fish, PUFA salmon, PUFA eel and PUFA sturgeon purchase. Involvement in healthy eating influenced PUFA fish, premium price PUFA fish and PUFA salmon purchase. Cognitive style did not influence PUFA fish and premium price PUFA fish purchase; nor, contrary to earlier research, did cognitive style and involvement interact to influence intended PUFA fish purchases.