Effects of Macrophyte Bed Architecture on Largemouth Bass Foraging: Implications of Exotic Macrophyte Invasions

Abstract

Invasive, canopy‐forming macrophyte species such as Eurasian watermilfoil Myriophyllum spicatum and hydrilla Hydrilla verticillata are now widespread throughout North American lakes and reservoirs. However, their effects on economically and ecologically important species such as largemouth bass Micropterus salmoides are insufficiently understood. Canopy‐forming exotic macrophytes typically displace structurally diverse native macrophytes. In aquaria, we tested whether exotic macrophyte canopies negatively affect age‐0 largemouth bass foraging success compared with diverse macrophyte assemblages. In addition, we explored the relative effects of macrophyte density, and prey density of bluegills Lepomis macrochirus on largemouth bass foraging success. Bluegill prey density did not significantly affect largemouth bass foraging success. However, largemouth bass experienced shorter search times and greater attack and consumption rates in moderate plant density treatments (compared with dense) and diverse plant treatments (compared with canopy monocultures). Effects of macrophyte density and architecture (diverse versus canopy monoculture) on largemouth bass foraging success were similar in magnitude. Our results indicate that among lakes, the relative importance of macrophyte density and architecture to largemouth bass foraging will depend upon the extent to which each factor influences structural complexity.

Simple relationships to predict attributes of fish assemblages in patches of submerged macrophytes

“…In our study, macrophyte biomass, volume and proportional volume were strongly correlated with fish density and species richness, a pattern also observed in other studies (Valley & Bremigan, 2002;Crawley et al, 2006). The recurrence of these relationships in three independent sites of the reservoir supports the pattern, suggesting that macrophytes play an important role influencing fish distribution in littoral areas.…”

Monitoring freshwater fish in Florida lakes using electrofishing: Lessons learned

“…Monitoring freshwater fish in Florida lakes abundance of aquatic vegetation can have impacts on fish populations, both by food web effects (Crowder and Cooper 1982) and structural habitat effects (Valley andBremigan 2002, Pratt andSmokorowski 2003). Plant communities and their associated epiphytic algae support macroinvertebrates, which in turn provide a food resource for forage fish consumed by piscivores.…”

Largemouth bass consumption demand on hatchery rainbow trout in two Washington lakes

“…Macrophyte architecture and littoral habitat complexity have been studied extensively and found to influence largemouth bass predation on prey such as bluegill (Lepomis macrochirus), fathead minnows (Pimephales promelas) and crayfish (Savino and Stein 1982, 1989, Bettoli et al 1992, Dibble and Harrel 1997, Trebitz et al 1997, Ward and Neumann 1998, Valley and Bremigan 2002. However, little is known how littoral habitat complexity influences largemouth bass predation on salmonids.…”