title: Evidence of natural reproduction of Atlantic sturgeon in the Connecticut River from unlikely sources.
abstract: Atlantic Sturgeon is listed under the U.S. Endangered Species Act as five Distinct Population Segments (DPS). The "endangered" New York Bight (NYB) DPS is thought to only harbor two populations; one in the Hudson River and a second smaller one in the Delaware River. Historically, the Connecticut River probably supported a spawning population of Atlantic Sturgeon that was believed extirpated many decades ago. In 2014, we successfully collected pre-migratory juvenile specimens from the lower Connecticut River which were subjected to mitochondrial DNA (mtDNA) control region sequence and microsatellite analyses to determine their genetic relatedness to other populations coastwide. Haplotype and allelic frequencies differed significantly between the Connecticut River collection and all other populations coastwide. Sibship analyses of the microsatellite data indicated that the Connecticut River collection was comprised of a small number of families that were likely the offspring of a limited number of breeders. This was supported by analysis of effective population size (Ne) and number of breeders (Nb). STRUCTURE analysis suggested that there were 11 genetic clusters among the coastwide collections and that from the Connecticut River was distinct from those in all other rivers. This was supported by UPGMA analyses of the microsatellite data. In AMOVA analyses, among region variation was maximized, and among population within regions variation minimized when the Connecticut River collection was separate from the other two populations in the NYB DPS indicating the dissimilarity between the Connecticut River collection and the other two populations in the NYB DPS. Use of mixed stock analysis indicated that the Connecticut River juvenile collection was comprised of specimens primarily of South Atlantic and Chesapeake Bay DPS origins. The most parsimonious explanation for these results is that the Connecticut River hosted successful natural reproduction in 2013 and that its offspring were descendants of a small number of colonizers from populations south of the NYB DPS, most notably the South Atlantic DPS. Our results run contrary to the belief that re-colonizers of extirpated populations primarily originate in proximal populations.
authors.affiliation: Marine Fisheries Division, Connecticut Department of Energy and Environmental Protection, Old Lyme, Connecticut, United States of America.
authors.forename: Tom
authors.initials: T
authors.lastname: Savoy
authors.affiliation: Department of Environmental Medicine, New York University School of Medicine, Tuxedo, New York, United States of America.
authors.forename: Lorraine
authors.initials: L
authors.lastname: Maceda
authors.affiliation: Department of Environmental Medicine, New York University School of Medicine, Tuxedo, New York, United States of America.
authors.forename: Nirmal K
authors.initials: NK
authors.lastname: Roy
authors.affiliation: Warnell School of Forestry and Natural Resources, University of Georgia, Athens, Georgia, United States of America.
authors.forename: Doug
authors.initials: D
authors.lastname: Peterson
authors.affiliation: Department of Environmental Medicine, New York University School of Medicine, Tuxedo, New York, United States of America.
authors.forename: Isaac
authors.identifier: http://orcid.org/0000-0002-9652-513X
authors.initials: I
authors.lastname: Wirgin
mesh_terms: D000818:Animals; D003237:Connecticut; D056727:Endangered Species; D005399:Fishes / Q000502:physiology*; D012098:Reproduction; D045483:Rivers; D014481:United States