Ecology of Freshwater Fish 2008

"Fish feeding in changing habitats: effects of invasive macrophyte control and habitat complexity"
 

K. Kovalenko, E. D. Dibble, R. Fugi

Abstract – Many freshwater lakes have been invaded by non-native
aquatic plants. Although managing the invasions is necessary to restore
native macrophytes, little is known about the effects of invasive
macrophyte eradication on fish foraging. This study was designed to
determine whether fish feeding was affected by large-scale changes in plant
composition after selective control of invasive Eurasian watermilfoil,
Myriophyllum spicatum, and whether feeding was correlated with habitat
complexity or abundance of invasive plants on a smaller scale. Popnets
were used to collect plants, invertebrates and fishes in the littoral zone of
four Minnesota lakes twice a year for 4 years. The degree of stomach
fullness in fishes was not correlated with the proportion of invasive plants
or habitat complexity. Bluegills, the most abundant fish species, exhibited
high selectivity for Diptera and their preferences varied little in different
plant habitats. Changes in niche width of bluegills were not consistent with
invasive plant control. Overall, invasive macrophyte control with timely
restoration of the native plant community did not affect the characteristics
of fish feeding we investigated. This study also contributes to our
understanding of fish–macroinvertebrate interactions as a function of
habitat complexity.