Large‐scale, seasonal habitat use and movements of yellow American eels in the St. Lawrence River revealed by acoustic telemetry

Abstract

Large‐scale habitat use and movements of yellow American eels (Anguilla rostrata) from the St. Lawrence River were examined using acoustic telemetry from early summer to late fall in 2010 and 2011. Sixty‐seven eels were tagged, and their passage or presence was recorded using fixed acoustic arrays covering a 400 km distance along the St. Lawrence River and Estuary. Sixty‐four per cent of the 67 tagged eels were detected. Most eels were detected at only one array; the closest to their release location and at several occasions during the tracking period, suggesting a high proportion of freshwater residency in the upstream part of the St. Lawrence River. Downstream movements towards the brackish estuary (63–418 km distance) were demonstrated for 16.4% of the eels, particularly for those caught at the most downstream site that is close to the brackish estuary. Our results strongly suggest a lower activity of freshwater resident yellow eels during summer, a behaviour that may be related to day length, which defines time available for their nocturnal foraging. Indeed, yellow eels were detected primarily at night; no effect of moon phase was revealed. Movements in the vicinity of arrays (up to 116 km in the fluvial estuary) were suggested and smaller‐scale movements within Lac St. Louis were demonstrated, highlighting a yellow‐eel home range far more extensive than previously reported in smaller systems. Evidence for within‐season homing and site fidelity is also reported.

Diel and seasonal movements of silver eels, Anguilla dieffenbachii, emigrating from a lake subject to hydro‐electric control

“…In the present study, early‐season migrating A. dieffenbachii frequently took several weeks to reach Tuatapere, whereas late‐season A. dieffenbachii achieved this in a day or less. This behaviour is similar to the seasonal reduction in transit time noted for A. rostrata (Béguer‐Pon et al, ) and A. anguilla (Aarestrup et al, ). Presumably late‐season eels are under some behavioural pressure to reach the estuarine area within the optimum time of seaward egress.…”

Using a multi-criteria approach to assess post-release recovery periods in behavioural studies: study of a fish telemetry project in the Seine Estuary

“…These authors also mentioned a post-release downstream movement of 4,300 m for an individual that returned 12 h later to establish a refuge 640 m downstream of the release site. This rhythmic pattern of activity was recently confirmed for the American eel Anguilla rostrata [38].…”

Site fidelity, diel and seasonal activities of yellow‐phase Japanese eels (Anguilla japonica) in a freshwater habitat as inferred from acoustic telemetry

“…Numerous telemetric studies have been carried out on the Atlantic eels A. anguilla and A. rostrata and the New Zealand eels Anguilla australis and Anguilla dieffenbachii. Furthermore, while most eels overwinter in the same habitat as the one they occupy at other times of the year (Ovidio et al, 2013), some move from brackish water estuaries to freshwater rivers to overwinter (Béguer-Pon et al, 2015;Hedger et al, 2010). These studies have shown that yellow eels are principally nocturnal (Hedger et al, 2010;Jellyman & Sykes, 2003;Walker et al, 2014) and have decreased activity during winter.…”

“…They have described the movements and time and space utilisation of eels in rivers (Jellyman & Sykes, 2003;Ovidio, Seredynski, Philippart, & Nzau Matondo, 2013) and estuarine habitats (Béguer-Pon et al, 2015;Hedger, Dodson, Hatin, Caron, & Fournier, 2010;Parker, 1995;Simpfendorfer, Olsen, Heupel, & Moland, 2012;Thibault, Dodson, & Caron, 2007;Walker, Godard, & Davison, 2014). Numerous telemetric studies have been carried out on the Atlantic eels A. anguilla and A. rostrata and the New Zealand eels Anguilla australis and Anguilla dieffenbachii.…”

“…Fixed-array acoustic telemetry has been shown to be an effective method for determining the movement patterns of anguillid eels (Béguer-Pon et al, 2015;Walker et al, 2014). However, this method only provides rough estimates of eel positions based on their proximity to receivers and cannot be used to detect movements unless the eels move several hundred metres or more; and even where the positions of eels could be estimated, their tracking durations were short.…”