Interannual variation in spawning success of striped bass (Morone saxatilis) in the Saint John River, New Brunswick

Abstract

Barriers such as dams have been cited as a serious threat to striped bass survival, especially when they affect or impede migration and access to spawning grounds. On the Saint John River, New Brunswick, the installation of the large Mactaquac Dam in the immediate vicinity of a historic striped bass spawning location was suspected to have caused the arrest of striped bass reproduction and the collapse of the native striped bass population. In 2014, juvenile striped bass of confirmed Saint John River origin were documented in the river for the first time since 1979. In the current study, we examined juveniles from 6 years of sampling to determine corresponding years of successful recruitment. We also tracked adult striped bass matching the ancestry of native Saint John River juveniles to determine the timing and location of spawning. Over 5 years, we observed an annual upstream migration by adult striped bass to historic spawning areas near Fredericton, identified a dominant year class of Saint John River origin juveniles reproduced in 2013, and linked the apparent successful production of year classes to definable discharge conditions, that is, extended periods of sustained flow >36 hr downstream from the Mactaquac Dam. The results of this study suggest important first management actions towards recovering and sustaining the re‐discovered striped bass population in the Saint John River, New Brunswick.

Genomic population structure of Striped Bass (Morone saxatilis) from the Gulf of St. Lawrence to Cape Fear River

“…Multistate emergency management measures implemented by the ASMFC in the United States resulted in the recovery of most US populations during the 1990s and 2000s (ASMFC, 2019; Richards & Rago, 1999), although abundance estimates have since declined in the 2010s (ASMFC, 2019). In Canada, the closure of commercial fisheries and restrictions on recreational fishing led to the recovery of some populations (Miramichi River and Shubenacadie River) and not others (Saint John River, Annapolis River, and St. Lawrence River; Andrews, Linnansaari, Leblanc, Pavey, & Curry, 2019).…”

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

“…This listing was a result of the apparent loss of recruitment in 2 of the 3 known striped bass spawning rivers within the Bay of Fundy: the SJR (New Brunswick) and the Annapolis River (Nova Scotia). The Shubenacadie River in Nova Scotia currently remains as the region's sole recognized spawning location (but see Andrews et al 2020a).…”

“…Stock declines in the SJR attributed to unregulated commercial harvest occurring until 1978 (Andrews et al 2017) likely compounded upon the impact to spawning habitats observed in the downstream vicinity of the large Mactaquac Dam following its completion in 1968 (Bradford et al 2015, Andrews et al 2017, 2020a. Concomitantly, there has been no evidence of spawning or recruitment through infrequent searches since the mid-1970s (Dadswell 1975, DFO 2007, Andrews et al 2017.…”

“…Juvenile striped bass were last reported in the SJR in 1979 (M. J. Dadswell, 1982 memorandum to R. Wilson, Environmental Protection Service;reviewed in Andrews et al 2017); however, 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, Andrews et al 2020a.…”

“…Dadswell, 1982 memorandum to R. Wilson, Environmental Protection Service;reviewed in Andrews et al 2017); however, 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, Andrews et al 2020a. Juvenile striped bass typically remain in their natal rivers for the first 2 yr of life (Fay et al 1983, Greene et al 2009 but can also disperse along coastal regions and among adjacent rivers as youngof-the-year (Douglas et al 2001, Robinson et al 2004.…”