Theses and Dissertations


Title: Population Assessment of White Bass in Four Alabama Reservoirs

Name: Lovell, Richard Graves

Degree: MS

Chair: Michael J. Maceina

Resides:

University: Auburn University

Location: Auburn, Alabama

Date: 2000

Pages: 74

Keywords: white bass,reservoir management,population dynamics

Abstract:

Population characteristics including age, growth, mortality, relative weight, year-class formation, fillet weight, and fecundity of white bass Morone chrysops in four Alabama reservoirs were documented to describe population dynamics and the effects of different minimum length limits on these fisheries. Fish were collected in March and April 1999 and 2000 with DC electrofishing in Jordan, Mitchell, Martin, and Eufaula reservoirs. In addition, larval white bass were sampled in Martin and Eufaula Reservoirs in spring 1999 and 2000 to document larval abundance, spawning time, and identify factors related to larval appearance. Minimum length limits (229, 254, 305, and 356 mm) were simulated for white bass populations in Jordan, Eufaula, and Martin Reservoirs with respect to yield and numbers harvested. White bass from Jordan Reservoir grew faster, had higher fillet weights and expressed higher relative weights compared to the other reservoirs. Relative weight positively associated to fillet weight of white bass from Jordan, Mitchell, and Eufaula Reservoirs. Female white bass typically grew faster than males. Females expressed higher relative weight than males in Jordan Reservoir: however, males expressed higher relative weight than females from Martin Reservoir. Year-class formation was relatively stable in Lake Martin, where annual survival rates ranged from 43 to 58%. White bass year class strength was more variable in the Coosa River impoundments, where large year-classes were related to higher discharge from January to March. However, the formation of strong and weak year classes was generally synchronous among reservoirs. Female white bass from Jordan Reservoir produced more and slightly smaller eggs than fish from Martin Reservoir. Larval white bass densities were higher in Lake Eufaula than Lake Martin both years. First appearance of larval white bass ranged from the last week of March to the second week of April in both systems with water temperatures from 15.5 to 26.0° C. Appearance of larval white bass did not appear related to flow conditions in Lake Eufaula, but higher discharges in late March - early April were associated with larval appearance in Lake Martin. At a conditional natural mortality rate of 30% and exploitation greater than 30%, predicted yield in weight of white bass was slightly higher with the 305 mm minimum length limit in Jordan Reservoir. Minimum length limits greater than 229 mm did not increase yield in weight at conditional natural mortalities of 30 to 50% in Eufaula and Martin Reservoirs, regardless of exploitation. Higher minimum length limits dramatically reduced the number of fish available for harvest. White bass typically grow fast, but they are short-lived, thus in most cases, harvesting as many as possible would probably maximize yield.

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