A five-year summary of water quality, zooplankton, and fishes in the open waters of Lake Erie’s Presque Isle Bay

Abstract

Long-term monitoring of freshwater ecosystems is critical to understanding how these systems change over time. Our efforts have focused on the open waters of Lake Erie’s Presque Isle Bay (PIB) in Erie, Pennsylvania. The bay serves as an important economic and recreational body of water to the Erie region. Over the last several decades, the bay has undergone numerous water-quality changes and has been well studied, but no researchers have monitored PIB on a continuous basis. In the summer of 2017, a monthly monitoring program was started that focuses on detecting changes in water-quality as well as zooplankton and fish communities. Monitoring is focused from June through November each year. Sampling occurs each month in the same location aboard the RV Environaut. Here, data collected from 2017 through 2021 are presented to document changes in water quality, zooplankton, and fishes in the open waters of PIB. Analyses of variance (ANOVA) revealed a strong seasonal pattern and among-year variation in many water quality and fish parameters. Across the five-year period, linear regression revealed significant decreases in pH, Z_1% (the depth at which 1% of the light from the surface remains), and juvenile copepod abundance that we link to changes in water level. Our data contribute to the growing body of literature that highlights the importance of studying the near-shore embayments and coastal wetlands in Lake Erie. These shallow areas often respond to environmental perturbations faster or differently than the open waters of the lake.