Migration, Gamete Biology and Spawning

Belpaire, Claude; Pujolar, José Martín; Geeraerts, Caroline; Maes, Gregory

doi:10.1201/b19925-13

Cited by 13 publications

(14 citation statements)

References 74 publications

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“…The eel population declines possibly result from oceanic changes (Castonguay, Hodson, Moriarty, Drinkwater, & Jessop, ), overfishing (Dekker, ; Haro et al., ; Tsukamoto, Aoyama, & Miller, ), contamination (Belpaire, Geeraerts, Evans, Ciccotti, & Poole, ; Belpaire, Pujolar, Geeraerts, & Maes, ), parasitism (Feunteun, ; Kirk, ) and blockage due to dams (Kettle, Asbjørn Vøllestad, & Wibig, ; Moriarty & Dekker, ). These suspected causes match the above‐mentioned components of global change: oceanic modifications resulting from global warming, overfishing corresponds to overharvesting of natural resources, the eel swimbladder parasite is an alien species, blockage due to dams is an example of habitat loss due to land use, and contamination is the direct result of the increased pollutant load.…”

Section: Introductionmentioning

confidence: 99%

Freshwater eels: A symbol of the effects of global change

Drouineau

Durif

Castonguay³

et al. 2018

Fish and Fisheries

117

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Temperate eels Anguilla anguilla (European eel), A. rostrata (American eel) and A. japonica (Japanese eel) are three catadromous species which have been declining since the 1970s/1980s despite their remarkable adaptive capacity. Because of their specific life cycles, which share distant oceanic spawning grounds and continental growth stage, eels are affected by five components of the global change: (a) climate change affecting larval survival and drift, (b) an increase in pollution leading to high levels of contamination exacerbated by their high lipid levels, (c) increasing fragmentation and habitat loss that reduce dramatically the amount of available habitats and induce increased spawner mortality, (d) the appearance of Anguillicola crassus a parasitic alien nematode that impairs spawning success, and (e) the impact of commercial and recreational fisheries for all life stages of eel. In this context, the rapid increases of pressures during the “Great Acceleration” have surpassed the adaptive capacity of eels. This illustrates that cumulative effects of global change can lead to the collapse of species, even in species that have amazingly high adaptive capacities.

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Section: Introductionmentioning

confidence: 99%

Freshwater eels: A symbol of the effects of global change

Drouineau

Durif

Castonguay³

et al. 2018

Fish and Fisheries

117

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“…The threat of diseases on wildlife animal conservation has been recorded in other animal species such as the Tasmanian devil ( Sarcophilus harrisii ) (Hamede, McCallum, & Jones, ) and huemul ( hippocamelus bisulcus ) (Vila et al, ). Furthermore, due to the characteristic of accumulating toxic compounds in the body and their ability to live in highly polluted habitats, eels are also considered a good sentinel candidate for assessing aquatic environmental chemical pollution (Belpaire, Pujolar, Geeraerts, & Maes, ) and considered as a chemical bio‐indicator for the water framework directive (Belpaire & Goemans, ).…”

Section: Introductionmentioning

confidence: 99%

First isolation of Flavobacterium psychrophilum associated with reports of moribund wild European eel (Anguilla anguilla) in Scotland

Soares

Walker

Elwenn

et al. 2019

Journal of Fish Diseases

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In late April 2015, the River Dee Trust informed Marine Scotland Science, Fish Health Inspectorate (FHI), that there had been observations of dead and moribund European eels on the River Dee. Later in May, the Spey Fishery Board also reported a number of moribund European eels in a rotary screw smolt trap on the River Spey. In total, 10 cases involving moribund eels were investigated in 2015 and one case in 2016. In addition, a health screen was conducted to investigate the potential presence of Flavobacterium psychrophilum in healthy eels and Atlantic salmon from the River Dee in 2015. Externally, the diseased eels demonstrated white patches in different locations of the body. In all cases, F. psychrophilum was detected by bacterial isolation and/or molecular methods. Three isolates were further characterized by whole‐genome sequencing (WGS) as belonging to sequence type 15 (ST15). Histological examination of diseased European eels revealed lesions at the level of the integument. The pathogen screen for F. psychrophilum in wild healthy fish tested negative by PCR. Further investigation is required to understand the pathogenicity of this bacterium on the health of eels and the potential impact on the wild salmonid population.

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“…This issue of adaptation to environmental variability is presently crucial because temperate eels have suffered dramatic collapses (Dekker, 2009;Dekker and Casselman, 2014;Jacoby et al, 2015), and A. anguilla is classified as critically endangered by the IUCN (Jacoby and Gollock, 2014a), while A. rostrata and A. japonica are classified as endangered Jacoby and Gollock, 2014b). Several factors have been proposed to explain these declines (Jacoby et al, 2015), including changes in oceanic conditions (Castonguay et al, 1994), contamination and habitat degradation (Belpaire et al, 2016;Byer et al, 2015), parasitism (Feunteun, 2002;Kirk, 2003), fishing pressure (Dekker, 2003a), fragmentation including massive habitat loss (Kettle et al, 2011), and hydroelectricity-induced mortality (Castonguay et al, 1994). In view of this situation, the European Commission introduced European Regulation N° 1100/2007, imposing a new set of measures designed to reverse the decline.…”

Section: Introductionmentioning

confidence: 99%

Impacts that cause the highest direct mortality of individuals do not necessarily have the greatest influence on temperate eel escapement

Mateo

Lambert

Tétard³

et al. 2017

Fisheries Research

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Temperate eels are three panmictic catadromous species with a long period of oceanic passive larval drift and large distribution areas in contrasting environments. Spatial patterns of life history traits have been observed, and are correlated with environmental gradients, and may arise from both adaptive phenotypic plasticity and genetic polymorphism. This raises the question of the effect of spatially heterogeneous anthropogenic pressures on these populations. In this context, we used Geneveel, an individual-based optimization model that includes both phenotypic plasticity and genetic polymorphism, to explore the effects of different kinds of anthropogenic pressures: glass eel and silver eel fisheries, obstacles to upstream migration, and turbine mortality. More specifically, we analyzed the effects of these pressures on five output variables: the number of escapees, the proportion of females, the proportion of slow growers, the mean length-at-silvering and the resulting egg production. Our results suggest that phenotypic plasticity could act as a compensatory mechanism that mitigates the effects of some pressures (glass eel fishery and obstacles to upstream migration) and could be a source of resilience for the population, while other pressures did not show any compensatory effect (silver eel fishery and turbine mortality). Therefore, global impacts are very hard to assess, and the pressure that kills the most individuals does not necessarily have the biggest impact on the spawning biomass.

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Migration, Gamete Biology and Spawning

Cited by 13 publications

References 74 publications

Freshwater eels: A symbol of the effects of global change

Freshwater eels: A symbol of the effects of global change

First isolation of Flavobacterium psychrophilum associated with reports of moribund wild European eel (Anguilla anguilla) in Scotland

Impacts that cause the highest direct mortality of individuals do not necessarily have the greatest influence on temperate eel escapement

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