Abstract
Environmental effects monitoring investigations in marine ecosystems are challenging, particularly in dynamic ecosystems like the Bay of Fundy. We applied new environmental deoxyribonucleic acid (eDNA) tools in an effort to augment the conventional scientific approaches used in monitoring programs gained from monitoring programs specific to tidal turbine projects. Our ultimate goal is to address regional regulatory concerns and increase stakeholder confidence related to monitoring efforts conducted to-date. eDNA is defined as short fragments of genetic material that have detached from an organism into non-living components of an ecosystem (e.g., air, water, sediment) and provides a useful tool for determining species presence in challenging places to access and sample, such as macrotidal environments in the Bay of Fundy. Moreover, recent studies showing a link between eDNA concentration and fish density/biomass reveal the great promise for eDNA tools to improve biodiversity assessments in the marine environments.
Our project objectives were to develop and refine species-specific primers for eDNA detection of striped bass, derive estimates of eDNA signal persistence in saline water, and assess whether relationships exist between striped bass densities and eDNA concentration. To accomplish this, we assessed the accuracy and precision of a hand-held point-of-need (PoN) tool which can analyze eDNA in-situ to confirm species identification in real-time versus conventional laboratory-based eDNA techniques. These objectives were achieved through a series of manipulative laboratory experiments conducted at Dalhousie University’s Aquatron facility.
The first of these experiments determined that striped bass eDNA was reliably detected using either of the laboratory-based or PoN platforms, with some variation observed in the estimates of eDNA concentrations derived from each. Next, a time series experiment established that eDNA in water samples collected within a 24-hour period of exposure to striped bass was reliably and consistently detectable with either platform. Our final experiment found that the linear relationship between eDNA concentrations and manipulated striped bass stocking densities was significant and positive based on results from each of the laboratory-based or PoN platforms.
Our results validate and advance eDNA approaches towards complementing previous and ongoing marine tidal energy monitoring efforts and demonstrate the potential for eDNA tools to quantify and identify the spatial and temporal distribution of fish species-at-risk in an open ocean environment. Future research priorities are discussed related to further laboratory-based validation, field study trials, and augmentation with existing marine tidal monitoring data to leverage regulatory and stakeholder confidence in effects monitoring results.