The Anadromous Hickory Shad (Clupeiformes: Clupeidae, Alosa mediocris [Mitchill 1814]): Morphometric and Meristic Variation

Abstract

10 The anadromous Hickory Shad Alosa mediocris (Mitchill, 1814) (Clupeiformes: 11 Clupeidae) is reviewed, specifically regarding morphometric and meristic variation. Despite its 12 long history as recognized species, few descriptions of Hickory Shad morphometric and meristic 13 characters exist in the literature. Most authors of the historic literature have failed to provide 14 capture location for specimens, analyze large numbers of Hickory Shad, or document how 15 morphometric and meristic characters of the species vary spatially. To address this information 16 gap, a total of 717 mature Hickory Shad were collected from 23 different locations in Maryland, and Florida using electroshocking, 18 gill net, or rod and reel. All specimens were frozen, thawed, and 17 morphometric characters and 19 four meristic characters were examined; a random subset (n = 463) were analyzed for an 20 additional four meristic counts of gill rakers. Overall specimens ranged from 206-389 mm SL 21 with a mean + SD of 278.41 + 27.69 mm, 232-435 mm FL with a mean of 310.98 + 30.35 mm, 22 and 272-508 mm TL with a mean of 365.62 + 35.52 mm. The linear relationships between FL 23and TL, and FL and SL, were investigated and found to be: TL = 1.169*FL + 1.660 (n=705, 24 r 2 =0.995) and SL = 0.909*FL -4.274 (n=717, r 2 =0.992). Substantial differences in character 25 means for many morphometric measurements were found between male and female specimens, 26suggesting strong sexual dimorphisms relating to shape. However, meristic characters did not 27show differences in character means by sex.