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

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.

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.

Anaerobic energy metabolism of the European eel,Anguilla anguilla L.

1983 ◽  
Vol 149 (4) ◽  
pp. 469-475 ◽  
Author(s):  
Aren van Waarde ◽  
Guido van den Thillart ◽  
Fanja Kesbeke
Keyword(s):  
Energy Metabolism ◽  
Anguilla Anguilla ◽  
European Eel ◽  
Anaerobic Energy

scholarly journals Behavioral diversity is maintained by a conditional strategy in a freshwater zooplankton

2019 ◽  
Vol 30 (4) ◽  
pp. 1001-1011
Author(s):  
G Adam Meyer ◽  
William A Nelson
Keyword(s):  
Population Growth ◽  
Intraspecific Diversity ◽  
Migration Behavior ◽  
Ecological Strategy ◽  
Conditional Strategy ◽  
Freshwater Zooplankton ◽  
Behavioral Diversity ◽  
Behavioral Switching ◽  
Alternative Behaviors ◽  
Multiple Behaviors

Abstract Many populations have intraspecific diversity in phenotype and ecological strategy, but the mechanisms maintaining such diversity are not fully understood. Multiple behaviors can be maintained either as a conditional strategy, where fitness depends on an individual’s phenotype, or as a mixed strategy, where alternative behaviors have similar fitness independent of phenotype. Using high-resolution depth and time sampling, we characterize 2 distinct diel vertical migration behaviors in a population of freshwater zooplankton (Daphnia pulicaria). Individuals in this population differ in their color phenotype and migratory behavior with red morphs upregulating hemoglobin and undergoing a deep migration and pale morphs not producing hemoglobin and undergoing a shallow migration. We experimentally manipulated the behavior of each phenotype in the field and measured population growth in their natural migration behavior as well as population growth in their alternative behaviors. Experimental populations of pale and red morphs under their natural migrations had roughly equal fitness, despite vast differences in environmental conditions. When forced to switch behaviors, pale morphs suffered reduced fitness, whereas red morphs had similar fitness compared with their natural migration. Our results suggest that although behavioral diversity may be promoted by the opportunity for alternative behaviors of equal fitness, the distinct physiological conditions required for survival in alternative behaviors limit the capacity for individual behavioral switching and likely maintain behavioral diversity as a conditional strategy.

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