Diet overlap of common and at-risk riverine benthic fishes before and after Round Goby ( Neogobius melanostomus ) invasi
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ORIGINAL PAPER
Diet overlap of common and at-risk riverine benthic fishes before and after Round Goby (Neogobius melanostomus) invasion B. L. Firth
. M. S. Poesch . M. A. Koops . D. A. R. Drake . M. Power
Received: 23 January 2020 / Accepted: 19 September 2020 Crown 2020
Abstract Round Goby (Neogobius melanostomus) has invaded high diversity tributaries of the Laurentian Great Lakes, including those supporting multiple species of conservation concern. The extent and magnitude of ecological impacts on benthic riverine fishes is poorly understood, especially changes in diet overlap and feeding strategy. We used a before-after study design to examine the impact of Round Goby on native benthic riverine fishes, including the Threatened Eastern Sand Darter (Ammocrypta pellucida) in the Sydenham River, Ontario, Canada. To evaluate shifts in diet overlap and feeding strategy, fishes were collected with multiple gears and the direct (diet overlap with Round Goby) and indirect (diet overlap among native benthic fishes) impacts of Round Goby
were assessed. Prior to the arrival of Round Goby, six ecologically significant diet overlaps occurred among the studied native benthic fishes; whereas, following arrival, 20 ecologically significant diet overlaps occurred, with 6 out of 8 species, including Eastern Sand Darter, showing significant, direct diet overlap with Round Goby. Fishes exhibiting significant diet overlap with Round Goby shifted feeding strategies to become more specialized, a change in feeding consistent with potential competitive effects. Although the long-term consequences of invasion-induced diet and feeding shifts remain poorly understood, increased competitive interactions suggested by diet overlap may be occurring between Round Goby and native benthic riverine fishes and may exacerbate the observed decline of native species.
Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10530-020-02366-7) contains supplementary material, which is available to authorized users.
Keywords Round Goby Eastern Sand Darter Invasive species Diet overlap Trophic ecology
B. L. Firth (&) M. Power Department of Biology, University of Waterloo, Waterloo, ON, Canada e-mail: [email protected] M. S. Poesch Department of Renewable Resources, University of Alberta, Edmonton, AB, Canada M. A. Koops D. A. R. Drake Great Lakes Laboratory for Fisheries and Aquatic Sciences, Fisheries and Oceans Canada, Burlington, ON, Canada
Introduction Numerous studies have documented the decline of native fishes following the establishment of aquatic invasive species (AIS) (e.g., Ogutu-Ohwayo 1990; Baxter et al. 2004; Canonico et al. 2005; Cucherousset and Olden 2011; Gallardo et al. 2016). However, fewer studies have identified the causal mechanisms or
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factors implicated in species’ declines, whether acting directly on a focal species or indirectly within a community (Simon and Townsend 2003). Competition has been
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