Habitat Utilization and Movement Patterns of Sub-Harvestable Largemouth Bass (Micropterus salmoides) in the Ohio River

ABSTRACT

Electrofishing surveys were conducted seasonally from summer 1998 through summer 2000 in main channel, embayment, and tributary macrohabitats of the Ohio River. Catch per unit effort (CPUE) was low within macrohabitats, averaging from 0.00 to 6.76 sub-harvestable largemouth bass (Micropterus salmoides)/hour. Embayment CPUE was higher than tributary or main channel CPUE except in spring 1999, when tributary CPUE was highest. Core use areas were calculated from biotelemetry data and ranged from 88 to 59,400 m², representing 0.02 to 89.00% of available study location macrohabitat. Bass movement was limited to nursery embayments or tributaries with infrequent movement to nearby main channel areas. Bass preferred a mixed microhabitat consisting of a combination of vegetation and woody debris. This mixed microhabitat was less common in main channel habitat assessments compared to tributaries and embayments. Core use areas of Ohio River sub-harvestable bass are larger than reported in impoundment studies (<11,684 m²), suggesting Ohio River habitat is poorer than other systems.