Date of Award

1-1-2011

Document Type

Campus Access Thesis

Department

Earth and Ocean Sciences

Sub-Department

Earth and Environmental Resources Management

First Advisor

Virginia Shervette

Abstract

Longnose gar (Lepisosteus osseus) were collected opportunistically during the South Carolina Department of Natural Resources (SCDNR) Anadromous Fish Group monitoring program for shad (Alosa sapidissima) and sturgeon (Acipenser brevirostrum and Acipenser oxyrinchus) during Jan-Jul 2007 and May-Sep 2008 (n=444). The aim of this study was to assess basic ecological aspects (reproduction, diet, and population characteristics) of longnose gar (Lepisosteus osseus) in estuarine waters of South Carolina. There are very few studies examining longnose gar populations inhabiting esturaine environments and none in estuaries of South Carolina. Dietary data were pooled from all stomachs and analysis included; percent numeric abundance (% N), percent total weight (% W), and percent frequency of occurrence (% F) were calculated for prey items along with an index of relative importance (IRI). Of the 308 gar stomachs sampled; in winter months 76% of stomachs examined were empty. In spring the percent empty decreased to 54%, and in summer the percent empty decreased further to 33%. Overall, fish were an important component of the diet, occurring in 56% of stomachs containing food. Of identifiable prey items, Atlantic menhaden held the highest %N, %W, %F, and %IRI. Gonads were examined for reproductive analysis, the total gonad weight (TGW) was used to determine the gonadosomatic index (GSI) for each fish. GSI varied significantly across months in females (ANOVA: F = 33.1, p < 0.001, df = 8); in January GSI was significantly lower than April, but significantly higher than mean GSI values from May. GSI also varied significantly across months in males (ANOVA: F = 17.1, p < 0.001, df = 8). More research illustrating similar ecological characteristics of longnose gar from adequate reference populations would be of tremendous value and add to the overall understanding of this species' role in estuarine waters of North America.

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