Shortnose sturgeon, Acipenser brevirostrum, is a small, endangered species which occurs in 19 estuary systems along the east coast of North America. These populations are considered as separate entities by the U.S. National Marine Fisheries Service although evidence of morphologic or genetic differentiation among populations has not been documented. The purpose of this study was to compare morphological and genetic attributes among shortnose sturgeon collected from the Kennebec and Androscoggin Rivers, Maine, and the Hudson River, New York. Six morphometric and five meristic characteristics were quantified, Multivariate and univariate analyses of covariance and variance were used to assess differences among populations. Our analyses provided evidence for distinct populations in the Androscoggin and Kennebec Rivers, but character differentiation was greater between fish from these two locations and the Hudson River. Analysis of morphometric characters indicated significant differences in fish shape among the three rivers, with Hudson River sturgeon differing from the Maine rivers for the characters of head length, snout length, and mouth width. Significant differences were observed for meristic characters, but pairwise comparisons did not reflect a clear pattern of variability. Sequencing of a portion of the mitochondrial DNA control region revealed 15 haplotypes among 73 total specimens from the three rivers. Shortnose sturgeon from the Kennebec and Androscoggin Rivers were different from each other (p = 0.0260); both differed significantly (p < 0.0001) from the Hudson River collection. Gene flow was estimated at approximately 7 female migrants per generation between the two Maine populations and about 1 per generation between each of the Maine populations and the Hudson River population. Such strong stock structuring among presumably recently established post-Pleistocene ( 10,000 yr) populations suggests that this species occurs in highly discrete units. Morphological and genetic variation observed in this study combined with current knowledge of life history attributes of shortnose sturgeon indicate that conservative management decisions are necessary until the patterns and extent of differentiation among populations species-wide can be investigated further.

EXPLOR_STEP=$WICRI_ROOT/Wicri/Eau/explor/EsturgeonV1/Data/Main/Merge

HfdSelect -h $EXPLOR_STEP/biblio.hfd -nk 001564 | SxmlIndent | more

HfdSelect -h $EXPLOR_AREA/Data/Main/Merge/biblio.hfd -nk 001564 | SxmlIndent | more

{{Explor lien
   |wiki=    Wicri/Eau
   |area=    EsturgeonV1
   |flux=    Main
   |étape=   Merge
   |type=    RBID
   |clé=     Pascal:01-0389151
   |texte=   Morphological and genetic variation among Shortnose sturgeon Acipenser brevirostrum from adjacent and distant Rivers
}}