Near dam spatio-temporal distribution of migrating elver and juvenile American eel (Anguilla rostrata) in the downstream reach of the Mactaquac Generating Station, Wolastoq | Saint John River, New Brunswick

Abstract

American eel (Anguilla rostrata) is a catadromous species native to the Wolastoq | Saint John River (WSJR), New Brunswick. In 1980, a complete absence of juvenile eels (elvers) was reported near the Mactaquac Generating Station (MQGS), possibly reflecting a velocity barrier. From 2015-2017, various surveying and trapping techniques were implemented within 20 km downstream of MQGS. It was determined that juvenile eels (of average length 116.5 mm ± 14.2 mm and median age 1 year) are present at MQGS throughout the summer months, with abundance peaking in mid- to late July. Spatial distribution at the MQGS was not random, with the northern bank seeing higher relative abundances, particularly close to the Accelerated Rearing Facility. Highest relative abundance occurred within the spillway structures. The majority of elver recaptures occurred within the spillway gate of their original capture, with low movement between the two separate spillways. An ideal future upstream passage structure would consider collection at both spillways and within all gates.