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Improving non-native fish larvae detection based on temporal habitat use.
Citation:
Peterson, Greg, J. Hoffman, A. Trebitz, C. Hatzenbuhler, H. Ramage, J. Barge, M. Pearson, W. Bartsch, AND J. Launspach. Improving non-native fish larvae detection based on temporal habitat use. IAGLR, Toronto, ON, CANADA, June 18 - 22, 2018.
Impact/Purpose:
The Great Lakes Water Quality Agreement, Annex 6 has resulted in the implementation of a U.S.-Canada, basin-wide aquatic invasive species early detection network. Monitoring efforts for fish have focused on adult fish surveys, but recent advances in DNA metabarcoding are making larval fish monitoring feasible as well. Larval fish monitoring is desirable, because, compared to adults, larvae are generally more abundant and more likely to be unintentionally transferred; however, the ecology of many non-native fish larvae is not well understood in the Great Lakes. This research will enhance our understanding of the factors the influence larval fish dispersion patterns and inform survey designs resulting in improved detection efficiencies.
Description:
As part of the development of an early detection monitoring strategy for non-native fishes, larval fish surveys have been conducted since 2012 in the St. Louis River estuary. Survey data demonstrates considerable variability in fish abundance and species assemblages across habitats and temporal scales. To optimize early detection monitoring we need to understand larval fish patterns of development and dispersion and the environmental factors that influence them. In 2016 we designed an experiment to assess the temporal variability in larval fish abundance and composition amongst habitats that differed in temperature, turbidity, and vegetation. We sampled larval fish bi-weekly at nine locations from mid-May to mid-July, including both upper and lower estuary to contrast river versus seiche influenced habitats. Temperature was logged every 15 minutes beginning in early April, and hydroacoustic surveys (Biosonics) were conducted in alternate weeks between fish sampling to quantify the development of vegetation. Temperature data show that shallow upper estuary habitats warm faster and have less among-site variability than similar habitats in the lower estuary. These and other habitat patterns are compared to larval fish abundance and assemblage data to assess temporal and spatial relationships that could be exploited for more efficient larval fish monitoring. [This abstract does not necessarily reflect U.S. EPA policy].