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Hg dynamics in fish around New York State following the invasion of round goby

Suresh Sethi, Lisa Cleckner, Roxanne Razavi, Randy Jackson, Lars Rudstam (Funded by NY Water Resources Institute)

The invasive fish round goby (Neogobious melanostomus) is rapidly expanding across New York inland waterbodies and is rapidly moving towards the densely populated Hudson River system.  After being recorded in Lake Erie and Lake Ontario in the early 1990s, they have since spread through the Erie Canal to Cross Lake, Onondaga Lake, Oneida Lake, Cayuga Lake, and possibly Seneca Lake (anecdotal evidence).  Where introduced, round goby quickly reach high biomass with densities of up to 70 fish/m2 observed in Cayuga Lake by 2016.  As an abundant new ecosystem component, round goby enter the foodweb and their impact on contaminant cycling is a management concern.  As predators, round goby foraging behavior potentially exposes them to high contaminant loads, consuming benthic invertebrates and filter feeding invasive mussels.  As prey, goby have been recorded in stomachs of almost all resident gamefish in invaded waterbodies.  Presently, the potential for goby to impact predatory gamefish contaminant loads, either through bio magnification or through growth dilution, is not known.  Here, we seek to fill that knowledge gap by providing information on both round goby and top predator contaminant loads pre- and post-goby invasions.  Building from existing contaminants data hosted by the NY State which provide a pre-goby baseline, our objectives are to test round goby and predatory gamefish for mercury across a range of invaded systems at the invasion front.  By examining goby and predator contaminants pre and post invasion across a range of lakes with varying environmental contaminant loads, we will be able to inform lake managers about anticipated contaminant responses in gamefish, providing data needed to inform NY fish consumption advisories as the invader moves across the landscape. In 2019, we completed the analysis of Hg in gobies and their predators, and completed a first analyses and report. More in depth analysis using bioenergetics models is planned for 2020.