The Warmwater Fish Community of Loomis Lake, Pacific County, Before and After Aquatic Vegetation Removal

Loomis Lake was surveyed in June of 2001 and June of 2005 by three-person teams using multiple gear types (electrofishing, gillnetting, and fyke-netting). These surveys bracketed a total-lake herbicide treatment conducted in 2002. Largemouth bass Micropterus salmoides, pumpkinseed Lepomis gibbosus, and yellow perch Perca flavescens, were the predominant species in both surveys, accounting for 97% of the fish sampled in 2001 and 94% of the sample in 2005. Growth rates for young pumpkinseed and yellow perch (age-1 and age-2) and largemouth bass (age-1) spawned post-treatment were significantly higher than pre-treatment growth rates. Post treatment, the size structures of all three species shifted toward larger fish, and the mean lengths of all three species increased. Post-treatment changes in relative abundance data were mixed and a proper comparison of pre- and post-treatment data may have been compromised by changes in gear efficiency due to vegetation removal. Consistent with published reports, the total-lake herbicide treatment of Loomis Lake appears to have provided a short-term benefit to fish growth and size-structure.