Habitat Suitability Modeling for the Reintroduction of Freshwater Mussels to the Cuyahoga River

Trimbath, Ryan; Schwartz, Celia

Freshwater Mussels (Unionidae) were historically present in the Cuyahoga River but have become nearly extirpated and “functionally extinct” from the lower portion of the river over the past centuries due to human activity (Tevesz et al. 2012, Haag and Williams, 2014). Cuyahoga Valley National Park (CUVA) aims to reintroduce freshwater mussels to the Cuyahoga River with the goal of establishing 2-4 diverse and healthy mussel beds within the park boundary. The first step in this process confirmed the readiness of the Cuyahoga River through growth and survivorship studies in 2021-2022. Here, we take the next step in this process by identifying target species for reintroduction and suitable sites for mussel bed formation. Historical analysis and consultation with local mussel experts resulted in a list of target species for reintroduction and identification of the top five species for initial efforts which includes Lampsilis siliquoidea (Fatmucket), Lampsilis cardium (Plain Pocketbook), Actinonaias ligamentina (Mucket), Potamilis alatus (Pink Heelsplitter), and Quadrula quadrula (Mapleleaf). Identification of suitable sites was done by creating a habitat suitability model for 15 river miles of the Cuyahoga River at CUVA using ArcGIS Pro. The model was informed by water depth, current velocity, and shear stress data generated by a HEC-RAS (Hydrologic Engineering Center River Analysis System) model provided by the US Army Corps of Engineers (USACE), as well as substrate data provided by a side-scan sonar survey of the river conducted by the US Fish and Wildlife Service (USFWS). Each variable was scaled according to mussel preference informed by a thorough literature review, and all the layers were synthesized into a habitat suitability model which identified the 11 best habitat patches for bed formation in the Cuyahoga River at CUVA. From these 11 patches a consultation call was organized with area experts during which additional information was incorporated (growth and survivorship, personal experience, access, etc.) and two sites (Rockside and Red Lock Meanders) including three patches were selected as the recommended locations for initial mussel reintroductions.