Empirical observations of the spawning migration of European eels: The long and dangerous road to the Sargasso Sea

Righton, David; Westerberg, Håkan; Feunteun, Éric; Økland, Finn; Gargan, Patrick; Amilhat, Elsa; Metcalfe, Julian D.; Lobón‐Cerviá, Javier; Sjöberg, Niklas; Simon, Janek; Acou, Anthony; Vedor, Marisa; Walker, Alan; Trancart, Thomas; Brämick, Uwe; Aarestrup, Kim

doi:10.1126/sciadv.1501694

Cited by 166 publications

(224 citation statements)

References 94 publications

Supporting

Mentioning

199

Contrasting

Order By: Relevance

“…It should be noted that the measured speeds were calculated over ground and do not take into account current speed and time spent at the seabed; the actual swimming speeds would therefore vary with these factors. The mean migration speed of the eels was similar to the mean migration speed of silver eels released at the Swedish coast of the Baltic Sea (mean 21.6 km/day range: 12.2–51.0 km/day; Westerberg et al., ), and also the rates reported for eels released in the Atlantic and Mediterranean (Righton et al., ).…”

Section: Discussionsupporting

confidence: 79%

Diving activity of migrating silver eel with and withoutAnguillicola crassusinfection

et al. 2018

View full text Add to dashboard Cite

Summary Infection with the swim bladder nematode Anguillicola crassus has been hypothesised to threaten the spawning migration success of the endangered European eel (Anguilla anguilla). To examine this assumption, we compared the swimming behaviour of one Anguillicola crassus infested eel in the North Sea and three parasite‐free eels in the Baltic using data recovered from data storage tags attached to migrating silver eels. In both areas, eel activity was characterized by frequent diving behaviour throughout the water column during the night, with reduced activity during the day. Despite substantial damage of the swim bladder, the behaviour of the infested eel from the North Sea was within the same range of migrating and diving activity parameters as the three parasite‐free eels from the Baltic Sea. All eels had a similar frequency distribution of descent or ascent speeds and a similar average horizontal migration speed. The diving speeds and dive ranges exclude the possibility that the eels were in continuous hydrostatic equilibrium during their migrations and suggests therefore that the role of the swim bladder in vertical migration is likely to be more complex than currently thought. Our results suggest that eels infested by Anguillicola crassus are capable of diving in a similar manner to uninfested eels during the first stretch of their spawning migration.

show abstract

Section: Discussionsupporting

confidence: 79%

Diving activity of migrating silver eel with and withoutAnguillicola crassusinfection

et al. 2018

View full text Add to dashboard Cite

show abstract

“…14]. For fishes, depth use is controlled by multiple ecological and physiological functions [15,16]. For pelagic species performing long-distant oceanic feeding migrations, vertical movements are often interpreted as searching and foraging behaviour with shifts in depth use often associated with alternation between these behavioural modes [17] or changes in prey fields [5,18].…”

Section: Introductionmentioning

confidence: 99%

Revealing the full ocean migration of individual Atlantic salmon

et al. 2018

View full text Add to dashboard Cite

Background: Knowledge of the complete horizontal migration and vertical movements of Atlantic salmon (Salmo salar L.) during the marine phase is important for understanding the link between individual processes and population recruitment. We studied the detailed migration behaviour of six post-spawned adult Atlantic salmon from a North Norwegian river, during the entire ocean migration, by using high-resolution light-based geolocation archival tags. Results:The fish performed long-distance migrations and utilized Arctic areas from the eastern Barents Sea, to areas of Jan Mayen Island, and north to Svalbard. Four of six individuals exhibited a strong fidelity towards Jan Mayen Island, particularly during winter, which may suggest that the ecological conditions in these waters may be important for overwintering. One fish displayed exclusive utilization of the Barents Sea, indicating that growth and survival of some individuals are entirely dependent on these waters. The fish displayed a pelagic behaviour and all individuals spent more than 83% of the time in the uppermost 10 m of the water column. There was a strong seasonal trend in diving intensity, with the number of dives increasing with day length, independent of individuals' spatial distribution. Diving depth was positively correlated with the depth of the mixed layer. Conclusions:The Atlantic salmon displayed large individual variation in horizontal migrations, utilizing different ocean areas north of the Arctic Circle. This means that, despite the overall fidelity towards northern latitudes, individuals from the same population may experience highly different ecological conditions, potentially contributing to within-population variation in growth and survival. The seasonal correlation between diving intensity and day length, and spatial correlation between diving depth and depth of the mixed layer, indicate that the overall depth use of the Atlantic salmon depends on both spatially independent seasonal factors, and dynamic oceanographic conditions that facilitate food aggregations. This is the first study of Atlantic salmon to present detailed information about individuals' continuous horizontal migration and simultaneous vertical movements during the entire ocean migration, thus providing novel information on how habitat use change throughout the ocean residency.

show abstract

“…to undertake a long (5-10,000 km) and slow (6-18 months) migration back to the spawning grounds (Feunteun, 2002;Righton et al, 2016).…”

mentioning

confidence: 99%

Migration behaviour and escapement of European silver eels from a large lake and wetland system subject to water level management (Grand‐Lieu Lake, France): New insights from regulated acoustic telemetry data

Trancart

Feunteun

Danet

et al. 2017

Ecology of Freshwater Fish

Self Cite

View full text Add to dashboard Cite

Current knowledge about the downstream migration of sexually mature European eels (Anguilla anguilla) remains incomplete, particularly in still water habitats such as lakes and wetlands subject to water level management. However, for the management of this endangered species, it is important to understand migration dynamics, and contribution to the breeding stock. This study aimed to assess the parameters that trigger and guide the migration of silver eels in the largest floodplain lake and associated wetlands in France (the sluice regulated Grand-Lieu Lake). A telemetry survey of 50 acoustic and PIT-tagged female silver eels was performed during the 2015-2016 migration period. We deployed a novel telemetric approach, using receivers to delimit several restricted virtual boxes to determine the instantaneous location of individuals and to transform simple discrete telemetric data into presence/absence data. The low numbers leaving the lake centre are probably explained by the lack of orienting water flows or other environmental clues, but whilst the fate of 34% (17/50) of the tagged eels is unknown, 18% (9/50) were caught by commercial fishermen. Modelling showed that detections were not clearly associated with environmental factors typically involved in riverine migrations (e.g. current velocity, atmospheric pressure and temperature) but they were particularly associated with higher and increasing water levels and, for eels exiting the lake, a sharp increase when sluice gates were opened to an effective gap of >75 cm. It is concluded that management of water levels and sluice gate opening during the migration period might aid escapement of silver eels.

show abstract

Empirical observations of the spawning migration of European eels: The long and dangerous road to the Sargasso Sea

Abstract: Fresh data on the timing and speed of the oceanic spawning migration of European eels suggest a new paradigm for spawning ecology.

Cited by 166 publications

References 94 publications

Diving activity of migrating silver eel with and withoutAnguillicola crassusinfection

Diving activity of migrating silver eel with and withoutAnguillicola crassusinfection

Revealing the full ocean migration of individual Atlantic salmon

Migration behaviour and escapement of European silver eels from a large lake and wetland system subject to water level management (Grand‐Lieu Lake, France): New insights from regulated acoustic telemetry data

Contact Info

Product

Resources

About