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A field observation of rotational feeding by Neogobius melanostomus
Citation:
Angradi, T. A field observation of rotational feeding by Neogobius melanostomus. Fishes. MDPI, Basel, Switzerland, 3(1):1-6, (2018).
Impact/Purpose:
The aggregated cost of aquatic invasive species to the Great Lakes Regions is over $100 million annually. Among the most damaging species are dreissenid mussels (Dreissena spp.) and the Round Goby (Neogobius melanostomus). Information about the life histories and ecology of these species is critical to understanding their impact on the Great Lakes. There is evidence of ecological links between species in the Great Lakes. During an underwater survey of benthic habitats in Lake Huron designed to assess the distribution of these species and to provide data for mapping substrates, a heretofore poorly documented interaction between these two species was observed. The purpose of this paper was to describe this interaction for the benefit of invasive species fish behavior specialists and scientists interested in the impacts of invasive species on the Great Lakes ecosystem.
Description:
Video documentation was obtained of the invasive benthic fish, Neogobius melanostomus, the round goby, feeding on crushed dreissenid mussels at a depth of 12 m in Georgian Bay of Lake Huron, Canada. Gobies used rotational or twist feeding to tear away particles from crushed mussels. At least 43 examples of this feeding maneuver occur in the video. Up to 120 round gobies/m2 were visible at a time in the video. Mean standard length of gobies was 37 mm. Mean standard length of fish exhibiting twist feeding was larger, 48 mm. Mean size of intact mussels in visible clusters was about 10x20 mm, a size which exceeds the gape width of the largest gobies observed in the video. Gobies are known to use twisting to wrest small attached mussels from the substrates which can be crushed by their pharyngeal teeth. We surmise the behavior observed in the video is an opportunistic manifestation of this inherent behavioral adaptation to exploit a temporary windfall of food.
