Evidence of a Genetically Distinct Population of Striped Bass within the Saint John River, New Brunswick, Canada

Abstract

Sound management of a species requires, among other things, careful consideration of their distribution and genetic structure throughout their range. Historically, there were three spawning populations of Striped Bass Morone saxatilis occurring within the Bay of Fundy, Canada (Shubenacadie River, Annapolis River, and Saint John River), but today the only known spawning population is found in the Shubenacadie River, Nova Scotia. The last spawning event recorded (albeit unsuccessful) in the Saint John River was in 1975 shortly after the completion of the Mactaquac Dam in 1968. Adult Striped Bass from other rivers frequent the Saint John River during much of the year, making the presence of adults uninformative about the status of spawning. In the absence of direct indicators of spawning, such as eggs and larvae, genomic tools can provide insight into the genetic origin of the juvenile Striped Bass in the Saint John River. Tissue samples were taken from Striped Bass (ages 1-3; 12.2-35.0 cm TL) captured in the Saint John River and compared with samples from the Shubenacadie River, Hudson River, and Chesapeake Bay. A doubledigest RAD-seq technique was used to identify 4,700 single nucleotide polymorphisms, and population structure was assessed using population differentiation statistics (F ST ) and genetic clustering algorithms. The F ST analysis found significant differences among all sample sites, albeit weak differences between Hudson River and Chesapeake Bay samples, and a global F ST of 0.101. Genetic clustering analyses and discriminant analysis of principle components both grouped samples into three clusters: the Shubenacadie River, the U.S. populations, and the Saint John River juveniles. Based on these findings and the current understanding of Striped Bass juvenile dispersal, there is strong evidence of a genetically distinct population of Striped Bass within the Saint John River. 1340 LEBLANC ET AL.

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

“…We present the most complete examination of Striped Bass genetic structure across their native range using SNP loci. Previous genetic studies of Striped Bass have used genetic markers such as RFLPs (e.g., Wirgin, Maceda, Stabile, & Mesing, 1997; Wirgin, Maceda, et al, 1993), VNTRs (Laughlin & Turner, 1996), mitochondrial sequences (e.g., Wirgin, Maceda, et al, 1997), microsatellites (Bentzen & Paterson, 2008; Brown et al., 2005; Gauthier et al., 2013; Wirgin et al., 2020), and SNP loci (LeBlanc et al., 2018) to assess the genetic structure of Striped Bass across portions of its range. Only two studies have included a thorough coverage of all major migratory populations (Hudson River to Roanoke River), and of those only Wirgin et al.…”

“…(2012) and modified as described in LeBlanc et al. (2018). Samples were randomized so that each lane contained individuals from multiple locations and sequenced using Illumina ® HiSeq™ 2,500 or Illumina ® HiSeq™ 4000 (San Diego) at Génome Québec Innovation Centre.…”

“…The Striped Bass, Morone saxatilis (Walbaum, 1792), is a facultative anadromous and economically important fish with a native range extending along the Atlantic coast of North America from the St. Lawrence River, Quebec, to the St John's River, Florida, as well as a native population in the Apalachicola–Chattahoochee–Flint river system in the Gulf of Mexico (Setzler et al., 1980; Wirgin, Currie, Roy, Maceda, & Waldman, 2005; Figure 1). Individuals from the Hudson River to the Roanoke River can move long distances, some moving 400–1000 km along the Atlantic Coast (Callihan, Harris, & Hightower, 2015; Kneebone, Hoffman, Dean, Fox, & Armstrong, 2014; Mather et al., 2010), and along with some Canadian populations are known to enter non‐natal rivers (Grothues, Able, Carter, & Arienti, 2009; Kneebone et al., 2014; LeBlanc et al., 2018). Migratory populations within the United States are currently managed as two separate stocks: the Roanoke River, and all US populations north of the Roanoke River (Atlantic States Marine Fisheries Commission (ASMFC, 2019)).…”

Consumption of Atlantic Salmon Smolt by Striped Bass: A Review of the Predator-Prey Encounter Literature and Implications for the Design of Effective Sampling Strategies

“…6 Dunning et al [38] conducted all sampling during winter-no smolt observed. 7 Gardinier and Hoff [40] sampled 13 striped bass >20 cm but reported stomach fullness collectively with samples from smaller striped bass-no smolts observed. * Southern Gulf of Saint Lawrence (SGSL).…”

“…The overlapping native range of striped bass (Morone saxatilis) and Atlantic salmon (Salmon salar) extends nearly 1500 km from the southern extreme of the Atlantic salmon range in the Hudson River, USA [1] to the northern extreme of the striped bass range in the Saint Lawrence River, Canada [2] ( Figure 1). Within this area,~300 rivers currently support Atlantic salmon populations (either native or re-introduced by stocking) [3,4] and six rivers (Hudson, Kennebec, Saint John, Shubenacadie, Miramichi, and Saint Lawrence) are recognized to support reproducing populations of striped bass [5][6][7].…”