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Comparison of early detection survey approaches during two new fish introductions
Citation:
Peterson, G., J. Hoffman, A. Trebitz, C. Hatzenbuhler, J. Myers, E. Pilgrim, AND S. Okum. Comparison of early detection survey approaches during two new fish introductions. Upper Midwest Invasive Species Virtual Conference, Duluth, MN, November 02 - 06, 2020. https://doi.org/10.23645/epacomptox.13146284
Impact/Purpose:
Under the Great Lakes Water Quality Agreement, there is a commitment for a bi-national program for aquatic invasive species early detection surveillance Great Lakes-wide. This work builds on invasive species early detection work conducted by EPA/ORD and other agencies. In this study we evaluate and compare differences in the effectiveness of different early detection approaches for non-indigenous fishes using data collected during actual introductions. Outcomes from this research will help improve early detection monitoring strategies in Great Lakes coastal systems.
Description:
A major component and challenge of aquatic non-indigenous species (NIS) prevention and management efforts is implementation of early detection monitoring (EDM) surveys. Assessing the performance of EDM surveys typically relies on surrogate performance metrics to estimate survey effectiveness absent any actual new NIS presence. However, models based on established or indigenous species may not be appropriate for evaluating detection effectiveness for new NIS. Recently, two newly introduced fishes, white bass (Morone chrysops) and gizzard shad (Dorosoma cepedianum), were detected in the St. Louis River estuary (SLRE) which includes the Great Lakes port of Duluth-Superior. Three different EDM survey approaches focusing on different biological targets (adult-juvenile, ichthyoplankton and eDNA) were ongoing during these introductions providing a rare opportunity to use actual NIS introduction data to compare and evaluate their effectiveness. Calculations of effort required to achieve 95% probability of detection (based on detection years) differed by survey approach but suggest that overall annual effort throughout the study provided 90-95% probability of detection for both species. Detection rates differed by EDM approach for both species. For example, eDNA appeared to be a more sensitive survey approach for gizzard shad while ichthyoplankton and adult-juvenile approaches appeared more sensitive for white bass. Relative detection in DNA-based (ichthyoplankton and eDNA) surveys versus morphological (adult-juvenile) surveys is discussed. Cohort calculations of captured fish suggest that white bass were present up to 5 years prior to initial detection while gizzard shad may have been detected in the first year of introduction.
URLs/Downloads:
DOI: Comparison of early detection survey approaches during two new fish introductions