scholarly journals Changes in Cadmium Concentration in Muscles, Ovaries, and Eggs of Silver European Eel (Anguilla anguilla) during Maturation under Controlled Conditions

Animals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 1027
Author(s):  
Joanna Nowosad ◽  
Dariusz Kucharczyk ◽  
Mariusz Szmyt ◽  
Joanna Łuczynska ◽  
Müller Tamás ◽  
...  
Keyword(s):  
Muscle Tissue ◽  
Cadmium Concentration ◽  
Anguilla Anguilla ◽  
Atomic Spectrometry ◽  
Commercial Fishing ◽  
European Eel ◽  
Cadmium Content ◽  
Controlled Conditions ◽  
Wet Weight ◽  
Artificial Maturation

This study determined the contents of cadmium (Cd) in the muscles, ovaries, and eggs of silver female European eels. The analysis of cadmium content was performed on female European eels caught during commercial fishing in freshwater in Warmia and Mazury (Poland), and then subjected to artificial maturation and ovulation processing under controlled conditions. The content of cadmium (Cd) in the tissues was determined by flameless atomic spectrometry using an electrothermal atomizer. The analysis showed statistically significant differences between the cadmium content in the muscles, ovaries, and eggs (p < 0.05) of female European eels. The lowest cadmium content was found in the muscle tissue (0.0012 ± 0.0001 mg kg−1 wet weight) and the highest in eggs (after ovulation) (0.0038 ± 0.0007 mg kg−1 wet weight). Moreover, a relationship was found between the cadmium content in the muscle tissue and the ovaries (R = 0.673; p = 0.0117) in the same fish. The movement of cadmium from tissues to oocytes may indicate a significant problem concerning this heavy metal content in the reproduction of European eel.

Challenges to quantifying glass eel abundance from large and dynamic estuaries

2017 ◽  
Vol 75 (2) ◽  
pp. 727-737 ◽  
Author(s):  
Sarah Walmsley ◽  
Julie Bremner ◽  
Alan Walker ◽  
Jon Barry ◽  
David Maxwell
Keyword(s):  
Large Scale ◽  
Anguilla Anguilla ◽  
Commercial Fishing ◽  
European Eel ◽  
Estuarine System ◽  
Glass Eel ◽  
The North ◽  
Adequate Sampling ◽  
South Shore ◽  
Glass Eels

Abstract European eel Anguilla anguilla recruitment into the rivers of the northeastern Atlantic has declined substantially since the 1980s. Monitoring of recruiting juveniles, or glass eels, is usually undertaken in small estuaries and rivers. Sampling of large-scale estuaries is rare, due to the size of the sampling area and the resources needed to provide adequate sampling levels. Here we describe surveys for glass eels in the UK’s largest estuarine system, the Severn Estuary/Bristol Channel. We sampled across a 20 km-wide stretch of the estuary in 2012 and 2013, using a small-meshed net deployed from a commercial fishing trawler, and the surveys yielded over 2500 glass eels. Eels were more abundant in the surface layer (0–1.4 m depth) than at depth (down to 8.4 m depth), were more abundant close to the south shore than along the north shore or middle of the estuary, and were more abundant in lower salinity water. Numbers were higher in the second year than in the first and eels were more abundant in February than April. The difficulties and logistics of sampling in such a large estuary are discussed, along with the level of resources required to provide robust estimates of glass eel abundance.

scholarly journals Bacterial and parasitic factors diagnosed in eel farmed in Poland in the years 2010-2014

2016 ◽  
Vol 72 (10) ◽  
pp. 647-651
Author(s):  
Elżbieta Terech-Majewska ◽  
Alicja Bernad ◽  
Stanisław Robak ◽  
Joanna Pajdak ◽  
Patrycja Schulz ◽  
...  
Keyword(s):  
Health Assessment ◽  
Anguilla Anguilla ◽  
Good Health ◽  
European Eel ◽  
Test Results ◽  
Aeromonas Sobria ◽  
Controlled Conditions ◽  
Etiologic Agents ◽  
Controlled Rearing ◽  
Glass Eels

European eel Anguilla anguilla L. is a fish species highly valued in European fisheries, currently reared under controlled conditions (Aquatic Recirculation System - RAS). In order to protect the health of fish, regular check-ups are carried out in specialized veterinary laboratories. Health hazards are recognized on the basis of clinical, pathological, microbiological, and parasitological surveys. The aim of the study was to analyze the results of health assessment of eels reared under controlled conditions, which was performed in the Diagnostics Laboratory of Fish and Crayfish Diseases, Department of Veterinary Hygiene, Voivodeship Veterinary Inspectorate in Olsztyn, in the period from 2010 to 2014. The results are presented according to the etiologic agents, divided into bacterial and parasitic diseases. In this period, 73 samples (100%) were examined, including 5 samples (6.85%) from glass eels and 68 (93.15%) from elvers. Microorganisms isolated from the collected material were mainly conditionally pathogenic, such as Pseudomonas fluorescens, Aeromonas hydrophila, Shewanella putrefaciens, Aeromonas sobria, Flavobacterium spp., and Chryseobacterium indologenes. The parasitological examination revealed infection with Trichodina spp., Ichthyophtirius multiphilliis, and Pseudodactylogyrus spp. The most frequently diagnosed were gill monogeneans, detected in 34 cases (75.55% of all positive parasitological test results). In 21 cases (61.8%) the infestation manifested itself as a disease. The remaining 13 cases were asymptomatic carriers (38.2%). The analysis shows that the main problem in the controlled rearing of eel are parasitic infestations, which may be endemic and pose a constant threat. Systematic monitoring and preventive measures are necessary throughout the rearing and fattening of fry to maintain a good health status of eels.

scholarly journals Size-related variation in fecundity of European eel (Anguilla anguilla)

2012 ◽  
Vol 69 (8) ◽  
pp. 1333-1337 ◽  
Author(s):  
Ruairí MacNamara ◽  
T. Kieran McCarthy
Keyword(s):  
Future Development ◽  
Anguilla Anguilla ◽  
Reliable Information ◽  
Focused Attention ◽  
European Eel ◽  
Marine Science ◽  
Related Variation ◽  
Management Policies ◽  
Artificial Maturation

Abstract MacNamara, R., and McCarthy, T. K. 2012. Size-related variation in fecundity of European eel (Anguilla anguilla). – ICES Journal of Marine Science, 69: . Declining European eel (Anguilla anguilla) recruitment has focused attention on conservation of potential spawners leaving continental waters. Fecundity of wild, seaward-migrating silver-phase eels was shown to be size-related and higher than previously reported from artificial maturation experiments. Reliable information on fecundity is essential for stock modelling and future development of eel management policies.

scholarly journals Methylmercury bioconcentration in muscle tissue of the European eel (Anguilla anguilla) from the Adour estuary (Bay of Biscay, France)

2007 ◽  
Vol 54 (7) ◽  
pp. 1031-1036 ◽  
Author(s):  
Ina Arleny ◽  
Hélène Tabouret ◽  
Pablo Rodriguez-Gonzalez ◽  
Gilles Bareille ◽  
Olivier F.X. Donard ◽  
...  
Keyword(s):  
Muscle Tissue ◽  
Anguilla Anguilla ◽  
European Eel ◽  
Bay Of Biscay

scholarly journals Estimates of escapement, exploitation rate, and number of downstream migrating European eels Anguilla anguilla in Ichkeul Lake (northern Tunisia)

2015 ◽  
Vol 73 (1) ◽  
pp. 142-149 ◽  
Author(s):  
Emna Derouiche ◽  
Besma Hizem Habbechi ◽  
Med. Mejdeddine Kraïem ◽  
Pierre Elie
Keyword(s):  
Size Range ◽  
Anguilla Anguilla ◽  
Distribution Area ◽  
Commercial Fishing ◽  
European Eel ◽  
Mark Recapture ◽  
Northern Tunisia ◽  
Silver Eels ◽  
Exploitation Rate ◽  
Ichkeul Lake

Abstract The European eel (Anguilla anguilla) stock has been declining for the last three decades and today, it is currently listed as endangered. The objective of this study was to quantify the escapement rate of silver eels to obtain an estimate of the future spawners migrating from the southern part of its distribution area in Tunisia. A mark–recapture experiment was conducted in Ichkeul Lake (Tunisia) between December 2013 and February 2014, covering the winter downstream run of eels. The size range of the downstream migrating eels was between 33 and 79 cm with 585.3 ± 156.77 g mean weight. The number of migrating silver eels was estimated to 342 221 (297 956–386 486), corresponding to a biomass of 200.2 (174.3–226.1) t, with a density of 23.55 (20.51–26.6) kg ha−1. The commercial fishing rate was estimated to be 18.8% (16.6–21.5%), which translates into an escapement rate of 81.2% (78.5–83.4%). The ratio current/pristine escapement was 0.69 for the entire migration period.

Metazoan Parasites and Health State of European Eel, Anguilla Anguilla (Anguilliformes, Anguillidae), From Tonga Lake and El Mellah Lagoon in the Northeast of Algeria

2018 ◽  
Vol 52 (4) ◽  
pp. 279-288 ◽  
Author(s):  
F. Bakaria ◽  
S. Belhaoues ◽  
N. Djebbari ◽  
M. Tahri ◽  
I. Ladjama ◽  
...  
Keyword(s):  
Brackish Water ◽  
Parasite Species ◽  
Anguilla Anguilla ◽  
European Eel ◽  
Health State ◽  
Component Community ◽  
Metazoan Parasites ◽  
Parasite Communities ◽  
High Dominance ◽  
Argulus Foliaceus

Abstract The aim of the study was to examine metazoans parasite communities of European eels (Anguilla anguilla) in freshwater (Tonga Lake) and brackish water (El Mellah lagoon) in the northeast of Algeria. Six parasite taxa were collected: one monogenean, Pseudodactylogyrus sp.; two crustaceans, Ergasilus sp. and Argulus foliaceus; two nematodes, Cucullanus sp. and Anguillicola crassus; one cestode, Bothriocephalus claviceps. Th e most prevalent parasite taxa in freshwater were Pseudodactylogyrus sp., A. crassus and Bothriocephalus claviceps; whereas in the brackish water, eels were infected mainly with A. crassus. Th e characteristics of the parasite component community structure revealed low parasite species diversity and high dominance values in eels from the two localities. Both communities were dominated by a single parasite species: Tonga eels by the monogenean Pseudodactylogyrus sp. and El Mellah lagoon eels by the nematode A. crassus, verified by high Berger-Parker dominance values of 0.76 and 0.87 respectively.

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