Use of Molecular Markers to Study the Effects of Environmental Impacts on Genetic Diversity in Brown Bullhead (Ameirus Nebulosus) Populations

Abstract

Conservation biology needs sound biological information in order to maintain biological diversity in the face of the current rate of loss. An important component of the information needed is the level of genetic diversity within and between populations, especially for those species faced with exposure to environmental stressors. We applied multilocus DNA profile analysis (highly variable number tandem repeats [HVNTR] and randomly amplified polymorphic DNA [RAPD] techniques) and allozyme analysis to test whether individuals from historically degraded sites display levels of genetic diversity different from individuals taken from reference sites. Four Lake Erie tributaries, two impacted and two reference sites, were the sources of brown bullhead (Ameiurus nebulosus) samples. Pairwise comparison of the sampled populations demonstrated an association of decreased genetic diversity with exposure of brown bullhead to stressors using both RAPD and HVNTR analysis.

A historical perspective on the “fish tumors or other deformities” beneficial use impairment at Great Lakes Areas of Concern

“…The susceptibility of fish to carcinogens is profoundly affected by genetic strain (Spitsbergen and Wolfe 1995). Murdoch and Hebert (1994) and Silbiger et al (2001) demonstrated a significant (p b 0.05) association of decreased genetic diversity, using multilocus DNA profile analysis, with exposure of brown bullhead to pollutants at impacted sites. Species differences certainly appear to play a role in neoplasia.…”

The relative roles of contemporary and ancient processes in shaping genetic variation of a generalist fish in a catchment dominated by agriculture

“…Creek chub are among the most common fishes in headwater streams throughout North America. Although fish populations may be abundant in ecological surveys, a history of periodic reductions in numbers could potentially reduce effective population size as detected using genetic markers in spatial comparisons with reference sites (Murdoch & Hebert, 1994;Silbiger et al, 2001). This hypothesis is further justified by the observation from an agriculturally dominated catchment that creek chub populations have been shown to exhibit several factors that contribute to population decline including reduced growth rates, delayed sexual maturity and reduced fecundity (Fitzgerald et al, 1999).…”

“…Species that rely on freshwater habitats may be particularly vulnerable to population declines due to the disproportionate human use of catchment resources (Dudgeon et al, 2006). Human alteration of habitat, water quality and hydrology are interrelated factors that have been demonstrated to contribute to reduced genetic diversity in freshwater systems (Pringle, 1997;Silbiger et al, 2001;Geist & Kuehn, 2005;Blum et al, 2012) either through genetic drift or through natural selection. For these reasons, genetic variation has become a key assay of population status in studies of disturbed aquatic systems (Gillespie & Guttmann, 1999;Belfiore & Anderson, 2001;Bagley et al, 2002;Blum et al, 2012).…”

Assessment of the “fish tumors or other deformities” beneficial use impairment in brown bullhead (Ameiurus nebulosus): I. Orocutaneous tumors

“…Old Woman Creek, located in north central Ohio, drains a primarily agricultural watershed (Matisoff et al, 2002). This site has been used extensively as a reference site for studies of environmental impacts on brown bullhead (Baumann et al, 1990;McFarland et al, 1999;Lin et al, 2001;Silbiger et al, 2001;Yang et al, 2003). However, metals and agricultural runoff (Klarer, 1988) as well as low PAH contaminants near bridges with creosote-treated wood (Johnston and Baumann, 1989;Lin et al, 1994) have been reported.…”