Alewife (Alosa pseudoharengus) and Blueback Herring (Alosa aestivalis) are anadromous fish species that are collectively referred to as river herring. Blueback Herring are known to range from the southern Gulf of St. Lawrence (Canada) southward to the St. Johns River, Florida (Greene et al. 2009). The range of Alewife is reported from the southern Gulf of St. Lawrence, including portions of Newfoundland southward to South Carolina (ICUN 2017). A recent range contraction to the north has been observed for Alewife with the current southern extent of range for this species more accurately assigned to river basins north of Cape Fear, North Carolina (North Carolina Division of Marine Fisheries and South Carolina Department of Natural Resources unpublished data). Both species are iteroperous (may spawn repeatedly), returning to freshwater systems in the spring when sexually mature to spawn. Alewife are known to more commonly utilize lentic sites (i.e., pond) for spawning and nursery habitat and spawn in temperatures beginning to range from 5-10°C (Loesch 1987). Blueback Herring are known to more commonly utilize lotic or riverine habitat for reproduction, but in the absence of co-occurring Alewife may use a wider range of habitats for spawning beginning in water temperatures ranging from 10-15°C (Loesch 1987; Greene et al. 2009).
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