Harvest and Mercury Levels of Striped Bass in Miramichi River, New Brunswick, Canada

Abstract The Striped Bass Morone saxatilis is an apex predator that supports recreational, commercial, and First Nations traditional fisheries in the Miramichi River, New Brunswick, Canada. Historic exploitation resulted in steep population declines, forcing a complete fisheries moratorium in 2000. After 13 years of recovery, a recreational fishery was reopened (May 2013) followed by a commercial fishery in 2018. These new opportunities for harvesting raised concerns about mercury levels in fish for human consumption as past levels have exceeded Health Canada guidelines of 0.5 mg/kg. We collected Striped Bass from the northwest Miramichi River in spring during the main recreational and commercial fishing seasons. Fish in the legal harvest slot for the recreational (50–65 cm TL) and commercial (50–80 cm TL) fisheries had total mercury in muscle tissue ranging from 0.08 to 0.43 mg/kg and from 0.08 to 0.63 mg/kg wet weight, respectively. Mercury levels in Striped Bass have decreased since the 1990s, but some individuals were close to or exceeded consumption guidelines. In addition, a preliminary angler creel survey revealed that only 8% of anglers retained their legal, three-fish limit (average harvest = 0.7 fish/angler/day). However, harvest of oversized fish was observed (11%), and a removal of ˜100,000 adults in the first month of the fishery by the recreational, commercial, and Indigenous fisheries is possible and represents a significant portion of the estimated adult population. We conclude that effective management of the Striped Bass fishery in the Miramichi River will require continued and more detailed angler surveys and population size and structure assessments accompanied by communication of current mercury levels in this species.