Growth of largemouth bass in low-salinity environments

Document Type

Article

Publication Date

1-1-1990

Abstract

We evaluated age and growth data for largemouth bass Micropterus salmoides inhabiting either a brackish marsh or a freshwater oxbow lake in south-central Louisiana. Marsh fish exhibited small size and reduced length at age. However, growth rates of older marsh fish equaled or exceeded those of freshwater largemouth bass. Relative weights of marsh fish indicated excellent condition during all seasons, whereas freshwater fish exhibited reduced condition in early spring and fall. Laboratory trials consisting of 120-d exposure of marsh and freshwater largemouth bass to four salinity levels (0, 4, 8, and 12‰) indicated a significant decrease in growth rate of freshwater largemouth bass with increasing salinity level up to 8‰. No such decrease was observed for marsh largemouth bass. All fish held at 12‰ stopped feeding within I week after the experiment began and died before the experiment ended. Sheared principal components analysis indicated differences in body shape between marsh and freshwater largemouth bass. We make the case that a complex interaction of several factors, including salinity, prey availability, habitat complexity, and predation risk, influences growth patterns among marsh largemouth bass. Characteristic body morphology and length at age of marsh fish suggest that largemouth bass adapt to biotic conditions in low-salinity marshes through an alternative growth strategy. © 1990 by the American fisheries society.

Publication Source (Journal or Book title)

Transactions of the American Fisheries Society

First Page

545

Last Page

552

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