Assessing Seasonal Occupancy of Winter Flounder (Pseudopleuronectes americanus) in Massachusetts Embayments Using eDNA.

McCall, Carly¹, Amanda Davis², Steve Voss², John Logan², Tim O’Donnell ¹Gloucester Marine Genomics Institute, Gloucester, MA, ²Massachusetts Division of Marine Fisheries, New Bedford, MA

Dredging projects are necessary to maintain and improve the navigational waterways that support the economic growth and sustainability of coastal communities. However, dredging can disturb wildlife habitats and result in detrimental consequences for economically important fish species like winter flounder (Pseudopleuronectes americanus) that use coastal embayments as spawning habitat. Turbidity and burial caused by dredging can lead to mortality of demersal eggs, which has prompted conservative dredging restrictions to protect winter flounder spawning success for up to six months of the year due to a lack of detailed information regarding the timing and location of winter flounder spawning within embayments. We have initiated an eDNA study by collecting and filtering (0.2µm pore size) 10-13 1L bottom water samples across six embayments monthly for a year, extracting DNA with the Qiagen DNeasy PowerSoil Pro kit, and applying a species-specific qPCR assay to detect winter flounder and better understand occupancy patterns in coastal Massachusetts. Preliminary results indicate seasonal and embayment-specific trends in winter flounder occupancy likely driven by benthic habitat and differences in behaviors among adult and young-of-year life stages. Completed data will be used to build a spatiotemporal occupancy model to inform dredging regulations that protect the winter flounder fishery while potentially identifying times and/or regions where restrictions can be relaxed.