Movements of juvenile and sub-adult striped bass Morone saxatilis in the Saint John River, New Brunswick, Canada

Sn Andrews,Ra Curry,Nm Leblanc,Sa Pavey,T Linnansaari

doi:10.3354/esr01074

Abstract

Juvenile striped bass (age-1) of distinct genetic ancestry were re-discovered in the Saint John River, New Brunswick in 2014 after a 35 yr hiatus of recognition. These juveniles were determined to be highly genetically divergent from all possible source populations, hypothesized to be of Saint John River ancestry, and thus considered evidence of the continued existence of the native stock. Successful recruitment of strong year classes of striped bass within the Saint John River, however, appears to be infrequent. We acoustically tagged and tracked juvenile and sub-adult striped bass (n = 37; age 2-4) in the Saint John River in both 2015 and 2016, and identified summer feeding and overwintering habitats that established an in-river residency. Following decades of poor or no recruitment of the native striped bass stock, it is now imperative that managers quickly include monitoring of juvenile and sub-adult striped bass and protection of their habitats in the conservation and recovery efforts for Saint John River striped bass.

Highlights

In 2012, the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) listed the Saint John River (SJR) striped bass as endangered as part of the Bay of Fundy Designatable Unit (COSEWIC 2012)
Genetic characterization of juvenile and sub-adult striped bass collected within the SJR was unable to match 36 of the 37 sampled the individuals monitored in this study to any adjacent stock (i.e. Shubenacadie River, Miramichi River, Kennebec River, Hudson River, Chesapeake Bay; Leblanc et al 2018, 2020) and they were determined to be of SJR ancestry
All 3 of these groups, including both pure and admixed individuals demonstrating SJR ancestry, were considered to have originated from spawning events occurring within the SJR as adult striped bass sharing the presumed SJR ancestry have yet to be detected departing from the SJR (Andrews et al 2020a,b; 7 yr of continuous acoustic tracking)

Summary

Introduction

In 2012, the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) listed the Saint John River (SJR) striped bass as endangered as part of the Bay of Fundy Designatable Unit (COSEWIC 2012). Environmental Protection Service; reviewed in Andrews et al 2017); age-1 striped bass were again captured in the river in 2014 and that year class was monitored annually thereafter (Andrews et al 2020a) These juveniles could not be genetically matched to any known spawning stock and it was concluded that they originated from historic SJR stock (Leblanc et al 2018, 2020, Andrews et al 2020a). Juvenile striped bass typically remain in Publisher: Inter-Research · www.int-res.com

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