Exploratory Analysis of the Cloadophora Dreissenid Relationship

Session: Connecting Management Needs and Science Information (2)

Seth Benson, US Geological Survey, sbenson@contractor.usgs.gov
Danielle Sopovski, US Geological Survey, dsopovski@contractor.usgs.gov
Kasia Przybyla-Kell, U.S. Geological Survey, kprzybyla-kelly@usgs.gov
Dawn Shively, USGS-Lake Michigan Ecological Research Station, dshively@usgs.gov
Mary Anne Evans, USGS, Great Lakes Science Center, maevans@usgs.gov
Meredith Nevers, U.S. Geological Survey - Great Lakes Science Center, mnevers@usgs.gov

Abstract

The introduction of dreissenid mussels to the Laurentian Great Lakes has had cascading ecological and economic impacts, including making possible a nuisance resurgence of the native alga Cladophora.  The proliferation of these two species has caused significant harm to fisheries, shipping, and industry.  While a great deal of study has been directed at both species, the comprehensive interactive effect of this altered ecosystem on Great Lakes ecology has not been established. In this study, live samples of Cladophora and driessenid mussels were collected in 2018 from several depths and locations by SCUBA divers across four of the Great Lakes most heavily impacted by Cladophora: Michigan, Huron, Erie, and Ontario. Cladophora samples were analyzed for three metrics: height, biomass, and percent coverage. Dreissenid mussels were analyzed for four metrics: biomass, total count, size, and percent coverage. Exploratory analysis was done with PCA, and multiple regression was used to establish relationships between the two. Early results indicate that 2018 was a low year for Cladophora growth and was high for Quagga mussel production. Understanding the interactive relationship of these two will help guide future management efforts to eradicate or limit multi-species invasions by exploiting characteristics of co-occurrence.