Identifier

etd-07072010-110814

Degree

Master of Science (MS)

Department

Renewable Natural Resources

Document Type

Thesis

Abstract

Since 1982, the Louisiana Department of Wildlife and Fisheries (LDWF) has stocked Florida-strain largemouth bass (FLMB; Micropterus salmoides floridanus) to incorporate Florida alleles into native populations (NLMB; M. s. salmoides) and enhance recreational fishing opportunities. I collected habitat data and largemouth bass samples from 12 LDWF stocked reservoirs and disconnected oxbow lakes to examine the relationships between reservoir characteristics, genetic identity, relative weight (Wr), liver somatic index (LSI), parasite loads, and back-calculated length-at-age. I examined the relationships between water body and genetic identity with Wr, LSI, and back-calculated length-at-age by ANOVA. Parasite loads were analyzed with ordinal regression. Principle component analysis was used to reduce the dataset into a smaller number of principal components and group the study lakes as habitat types. I then used ANOVA to assess whether Wr, LSI, or length-at-age were influenced by genetic strain or habitat type as represented by the principal components and logistic regression to determine whether principal component influenced the abundance of NLMB or non-native largemouth bass. Although similar across bass strains, Wr, LSI, and length-at-age varied by lake (all P<0.0001). Parasite loads were not significantly different between years or among water bodies or genetic strain. Based on the ANOVA results, shallow, nutrient rich lakes with high chlorophyll a concentrations and large littoral zones appeared to promote high Wr and non-native largemouth bass. Conversely, northern largemouth bass were more prevalent, and Wr was lower, in lakes with dense vegetation. Aquatic macrophytes may reduce foraging efficiency of larger, piscivorous fish while increasing survival of young-of-the-year largemouth bass. Reservoirs with little vegetative cover may reduce natural recruitment of resident largemouth bass allowing rapid genetic introgression. These findings may improve our understanding of the effects of FLMB stocking activities and provide the opportunity to modify stocking protocols to better achieve the management goals of the largemouth bass program.

Date

2010

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Kelso, William E.

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