Relationship between vegetation coverage and abundance, size, and diet of juvenile largemouth bass during winter

Juvenile largemouth bass Micropterus salmoides were collected by electrofishing during October through March 1992-1994 from coves (???25 ha) covered with aquatic macrophytes over 1-65% of their area. Mean total length of juvenile largemouth bass was highest in coves with the least vegetated cover, but increase in mean length between October and March was highest in coves having near 20% vegetation coverage. Catch per unit effort decreased between October and March; decreases were least at vegetation coverages near 10-20%, highest at coverages of 5% or less, and intermediate at coverages of 30-65%. By March, these disparate decreases contributed to the formation of a dome-like relationship between vegetation coverage and catch per unit effort. Consumption of fish foods was highest when vegetation coverage was low, but decreased asymptotically as coverage increased; consumption of invertebrate foods increased at low coverage, peaked near 20-30% coverage, and decreased at higher coverage. We suggest that greater length increases and greater abundance at 10-25% vegetation coverage were stimulated by a favorable blend of food availability and cover. Our results support reports that maximum recruitment of largemouth bass occurs at intermediate levels of vegetation coverage, and we further suggests that such increased production is reinforced during winter, when survival, invertebrate consumption, and length increases are highest at intermediate levels of vegetation coverage.