Estimation of glass eel ( Anguilla anguilla ) exploitation in the Severn Estuary, England

2020 ◽  
Vol 28 (1) ◽  
pp. 65-75
Author(s):  
Miran Aprahamian ◽  
Peter Wood
Keyword(s):  
Anguilla Anguilla ◽  
Glass Eel ◽  
Severn Estuary

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 Yield per recruit from stocking two different sizes of eel (Anguilla anguilla) in the brackish Roskilde Fjord

2015 ◽  
Vol 73 (1) ◽  
pp. 158-164 ◽  
Author(s):  
Michael I. Pedersen ◽  
Gorm H. Rasmussen
Keyword(s):  
Growth Rate ◽  
Scientific Information ◽  
Anguilla Anguilla ◽  
Silver Eel ◽  
Glass Eel ◽  
Recovery Plan ◽  
Yellow Eel ◽  
Roskilde Fjord ◽  
Yield Per Recruit ◽  
The Eu

Abstract Stocking of young eel is widely practised, as a measure, to meet the management target of the EU eel recovery plan. The target of the recovery plan is to increase the escapement to 40% silver eel biomass, relative to pristine conditions. The scientific information to predict the outcome in silver eel biomass from stocking is limited and may depend on whether translocation of wild glass eel or yellow eel is used, or if the stocked eels used are yellow eel from aquaculture. We evaluated the yield from stocking two different sizes, 3 and 9 g eels from aquaculture. A professional fishery recaptured 12.7% of the 3 g and 9.4% of the 9 g eels, originally stocked. Growth rate and mortality rate were different for the two stocked sizes, favouring the small eels. Brutto yield per recruit (YPR) was 13 and 9.2 g and netto YPR was 9.8 and 0.31 g for 3 and 9 g eel, respectively. We conclude that there seems to be no advantage in using larger 9 g eels compared with small 3 g eels for stocking.

scholarly journals Looking at the complex relationships between migration behavior and conditional strategy based on energy metabolism in the European glass eel (Anguilla anguilla)

2019 ◽  
Vol 696 ◽  
pp. 134039 ◽  
Author(s):  
Hengtong Liu ◽  
Jacques Labonne ◽  
Pascale Coste ◽  
Emmanuel Huchet ◽  
Elisabeth Plagnes-Juan ◽  
...  
Keyword(s):  
Energy Metabolism ◽  
Anguilla Anguilla ◽  
Migration Behavior ◽  
Conditional Strategy ◽  
Glass Eel ◽  
Complex Relationships

scholarly journals A stage-structured model to predict the effect of temperature and salinity on glass eel Anguilla anguilla pigmentation development

2005 ◽  
Vol 67 (4) ◽  
pp. 993-1009 ◽  
Author(s):  
C. Briand ◽  
D. Fatin ◽  
E. Ciccotti ◽  
P. Lambert
Keyword(s):  
Anguilla Anguilla ◽  
Effect Of Temperature ◽  
Structured Model ◽  
Glass Eel

Addressing the impact of mercury estuarine contamination in the European eel (Anguilla anguilla L., 1758) – An early diagnosis in glass eel stage based on erythrocytic nuclear morphology

2018 ◽  
Vol 127 ◽  
pp. 733-742 ◽  
Author(s):  
D. Castro ◽  
C.L. Mieiro ◽  
J.P. Coelho ◽  
S. Guilherme ◽  
A. Marques ◽  
...  
Keyword(s):  
Early Diagnosis ◽  
Anguilla Anguilla ◽  
Nuclear Morphology ◽  
European Eel ◽  
Glass Eel ◽  
The Impact

Selective pressure of fishways upon morphological and muscle enzymatic traits of migrating glass eels

2017 ◽  
Vol 74 (4) ◽  
pp. 445-451 ◽  
Author(s):  
T. Podgorniak ◽  
M. Angelini ◽  
E. De Oliveira ◽  
F. Daverat ◽  
F. Pierron
Keyword(s):  
Energy Metabolism ◽  
Selective Pressure ◽  
Condition Factor ◽  
Anguilla Anguilla ◽  
Aquatic Habitats ◽  
Size Selectivity ◽  
Glass Eel ◽  
Glass Eels ◽  
Species Specific

Fishways are built on obstacles to restore the connectivity between aquatic habitats. Our study investigated how species-specific fishways interact with interindividual trait differences among fish. We compared several groups of glass eels (Anguilla anguilla) climbing two types of fishways with those remaining below the water impoundments. We analyzed relative body condition factor, body length, mass, and in vitro activities and gene transcription levels of several enzymes involved in the energy metabolism (LDH, CS, CCO, PK). Differences among groups indicated that glass eel fish ladders can be size-specific, according to the type of substrate covering the surface of apparatus. Moreover, we found that climbing specific glass eel ladders can require higher endurance-related metabolic traits, triggering increased aerobic capacities. Increased aerobic efforts together with potential size selectivity of fishways should be taken into account when designing such devices and choosing appropriate location on eel migratory pathways.

scholarly journals Does tagging transparent fish increase predation risk? A laboratory study with glass eel (Anguilla anguilla) and sea bass (Dicentrarchus labrax)

2021 ◽  
Author(s):  
Arie Benjamin Griffioen ◽  
Woody Janssen ◽  
Timon Menke ◽  
Tony Wilkes ◽  
Hendrik Volken Winter
Keyword(s):  
Predation Risk ◽  
Laboratory Study ◽  
Dicentrarchus Labrax ◽  
Anguilla Anguilla ◽  
Sea Bass ◽  
Glass Eel

scholarly journals Rethinking swimming performance tests for bottom-dwelling fish: the case of European glass eel (Anguilla anguilla)

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
P. Vezza ◽  
F. Libardoni ◽  
C. Manes ◽  
T. Tsuzaki ◽  
W. Bertoldi ◽  
...  
Keyword(s):  
Water Temperature ◽  
Swimming Performance ◽  
Life Stage ◽  
Anguilla Anguilla ◽  
European Eel ◽  
Fish Swimming ◽  
Glass Eel ◽  
Swimming Time ◽  
Swimming Mode ◽  
Active Swimming

Abstract Systematic experiments on European eel (Anguilla anguilla) in their juvenile, early life stage (glass eel), were conducted to provide new insights on the fish swimming performance and propose a framework of analysis to design swimming-performance experiments for bottom-dwelling fish. In particular, we coupled experimental and computational fluid dynamics techniques to: (i) accommodate glass eel burst-and-coast swimming mode and estimate the active swimming time (tac), not considering coast and drift periods, (ii) estimate near-bottom velocities (Ub) experienced by the fish, rather than using bulk averages (U), (iii) investigate water temperature (T) influence on swimming ability, and (iv) identify a functional relation between Ub, tac and T. Results showed that burst-and-coast swimming mode was increasingly adopted by glass eel, especially when U was higher than 0.3 ms-1. Using U rather than Ub led to an overestimation of the fish swimming performance from 18 to 32%, on average. Under the range of temperatures analyzed (from 8 to 18 °C), tac was strongly influenced and positively related to T. As a final result, we propose a general formula to link near-bottom velocity, water temperature and active swimming time which can be useful in ecological engineering applications and reads as $${\rm{U}}_{\rm{b}}=0.174\cdot \left({{\rm{t}}_{\rm{ac}}}^{-0.36}\cdot {\rm{T}}^{0.77}\right)$$ U b = 0.174 · t ac - 0.36 · T 0.77 .

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