The effects of tournament fishing on dispersal, population characteristics, and mortaltiy of black bass in Lake Martin, Alabama
Type of DegreeThesis
Fisheries and Allied Aquacultures
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A great deal of black bass Micropterus spp. tournament activity occurs at Wind Creek State Park (WCSP), located at the north end of Lake Martin, Alabama. Because of the popularity of this location as a tournament processing site, displacement, dispersal, effects on body condition, and mortality of black bass due to tournament activities were examined. Tournament-caught black bass (N = 9,750) were coded wire tagged (CWT) and released at WCSP from fall 2003 to spring 2005. Electrofishing was used in fall 2004, spring 2005, and five times over a 42-day period in February - March 2005, to estimate dispersion, relative abundances, and relative weights of marked and unmarked fish over 300 mm total length. Initial mortalities were quantified by counting all dead fish at the release site. Radio telemetry was used to estimate delayed mortality, by lack of movement and mortality sensors, of largemouth bass M. salmoides and spotted bass M. punctulatus caught in tournaments from February to May 2005 and in September 2005. A high proportion (> 50%) of released tournament-caught largemouth bass remained within 3 km from the release site up to 3 months after release, and relative abundance of these fish tended to be higher near WCSP. However, after 3 months, the proportion of released tournament-caught largemouth bass declined near WCSP, which suggested that these fish dispersed from the release area. Tournament-caught spotted bass, tagged fall 2003 through spring 2004 and fall 2004, dispersed at a faster rate than largemouth bass, as proportions of tagged tournament-caught spotted bass within 6 km of the release site were low (3 - 5%) in 2004 and decreased to 0% in 2005. In addition, after forty-two days after release, very few tournament-caught spotted bass were collected within 4 km from the release site (< 10%). In Lake Martin, 7% of tagged largemouth bass and 3% of tagged spotted bass were recaptured by tournament anglers. Tournament recapture rates by anglers remained consistent over time for fish at large from 4 to 16 months. Previously caught fish at large for less than 4 months, expressed higher angler catch rates in spring 2005. Relative weights of tournament caught largemouth bass and spotted bass were either similar or lower than those for wild fish inhabiting Lake Martin. Thus, tournament activities at times likely affect the physiology of black bass even months after capture and release. Water temperature was positively related to initial mortality of largemouth bass and both initial and delayed mortality of spotted bass. Furthermore, tournament-caught spotted bass were more likely (62%) to experience delayed mortality within 10 days of release than largemouth bass (33%). I estimated that at water temperatures greater than 26°C, more than 50% of the tournament-caught black bass would die. In summary, over time black bass tended to disperse from tournament release sites in Lake Martin, although short-term accumulations did occur. At higher water temperatures, initial and delayed mortality rates were high and during these conditions, the use of the live-release boat should be discontinued. At times, angler capture and release of black bass were related to lower body condition which could adversely effected growth and reproductive output.