Monday, May 18, 2015
13:30 - 15:00

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13:30 - 13:45: / 101A EVALUATING THE INVASIVE HARRIS MUD CRAB AS A PREDATOR OF ZEBRA MUSSELS

5/18/2015  |   13:30 - 13:45   |  101A

EVALUATING THE INVASIVE HARRIS MUD CRAB AS A PREDATOR OF ZEBRA MUSSELS The trophic ecology of invasive species is integral to predicting their impacts, as release from predators can lead to explosive population growth outside their native range. Novel predators may act as a biological control, but quantifying their impact on invasive prey requires controlled manipulation. In the south-central United States, two invasive species, zebra mussels (Dreissena polymorpha) and Harris mud crabs (Rhithropanopeus harrisii), now coexist, with future range expansion likely. To identify factors key in regulating consumption of zebra mussels by Harris mud crabs, we conducted feeding trials to test how mussel size, crab body size, and claw morphology affected the rate and amount of mussels consumed. Larger crabs consumed more and larger mussels, but variation was high, with individual crabs consuming between 0 and 36 mussels over four days. All crabs preferred smaller mussels. Claw morphology was variable, but played a limited role in explaining variation in mussel selection. Our results suggest that Harris mud crabs may play an important role as a predator of zebra mussels, but we require an understanding of their consumption patterns to make accurate predictions.

Thayer Hallidayschult (Primary Presenter/Author), University of Oklahoma, thayer@ou.edu;


K. David Hambright (Co-Presenter/Co-Author), University of Oklahoma, dhambright@ou.edu;


13:45 - 14:00: / 101A MECHANISMS OF TOLERANCE AND DISTRIBUTION: COMPARING THE OXIDATIVE STRESS RESPONSE IN TWO INVASIVE DREISSENID MUSSELS UNDER DIFFERENT ENVIRONMENTAL STRESSORS

5/18/2015  |   13:45 - 14:00   |  101A

MECHANISMS OF TOLERANCE AND DISTRIBUTION: COMPARING THE OXIDATIVE STRESS RESPONSE IN TWO INVASIVE DREISSENID MUSSELS UNDER DIFFERENT ENVIRONMENTAL STRESSORS The invasive bivalves Dreissena polymorpha and D. bugensis have similar ecological niches and are significant pest species in North America and Europe. Dreissena bugensis has exhibited competitive advantages over D. polymorpha and is displacing D. polymorpha as the dominant dreissenid species in the North American Great Lakes. To understand this displacement, differences in tolerance to environmental stressors between the two species requires further study. Oxidative stress (OS) is a mechanism in which organisms mitigate environmental stressors, and monitoring OS biomarkers is useful to compare tolerance in dreissenid mussels. Mussels were evaluated for OS via lipid peroxidation and catalase activity following exposure to four stressors (e.g., high densities, temperature, hypoxia, and polychlorinated biphenyls). Dreissena bugensis had a stronger OS response than D. polymorpha indicated by higher levels of antioxidants (p < 0.05) or lower levels of lipid peroxidation (p < 0.05) in all the “stressed” conditions. This research demonstrates a correlation between tolerance to environmental stressors and antioxidant response. Higher tolerance to stress resulting from a stronger OS response may provide D. bugensis a competitive advantage over D. polymorpha.

Carly Nowicki (Primary Presenter/Author), Wayne State University, carlyjc21@gmail.com;


Donna Kashian (Co-Presenter/Co-Author), Wayne State University, dkashian@wayne.edu;


14:00 - 14:15: / 101A ARE QUAGGA MUSSELS SENSITIVE TO MICROCYSTIS AERUGINOSA BLOOMS? A COMPARISON WITH SENSITIVE DAPHNIA PULEX

5/18/2015  |   14:00 - 14:15   |  101A

ARE QUAGGA MUSSELS SENSITIVE TO MICROCYSTIS AERUGINOSA BLOOMS? A COMPARISON WITH SENSITIVE DAPHNIA PULEX Invasive dreissenid mussels inhabit waters that experience toxic cyanobacteria blooms of Microcystis aeruginosa. While these blooms might not cause widespread mortality, Microcystis may still impact dreissenids. We compared non-lethal endpoints of Microcystis exposure in quagga mussels, Dreissena rostriformis bugensis, to Daphnia pulex, a sensitive zooplankton routinely used in toxicity testing. Oxygen consumption, filtration rate, and two oxidative stress biomarkers were tested in mussels, and standard measurements of growth and fecundity were evaluated in Daphnia. Treatments included two strains of Microcystis (lab cultured and collected from Lake Erie), and the isolated toxin microcystin-LR (100 and 400 ug/L). Microcystis had no effect on oxygen consumption in Dreissena, but it decreased filtration rate (p<0.05). Oxidative stress response in mussels was elevated in the presence of microcystin-LR (p<0.05). Both Microcystis strains and microcystin-LR (400 ug/L) negatively affected Daphnia adult size (p<0.05). Only the Lake Erie Microcystis reduced fecundity in Daphnia (p>0.01). While Microcystis negatively impacted both species, Dreissena was more responsive to lower concentrations of microcystin-LR, suggesting that Dreissena populations may be particularly sensitive during bloom events where control measures may prove more effective.

Anna Boegehold (Primary Presenter/Author), Wayne State University, az1079@wayne.edu;


Donna Kashian (Co-Presenter/Co-Author), Wayne State University, dkashian@wayne.edu;


Karim Alame (Co-Presenter/Co-Author), Wayne State University, ea4852@wayne.edu;


Nicholas Johnson (Co-Presenter/Co-Author), USGS Great Lakes Science Center, njohnson@usgs.gov;


14:15 - 14:30: / 101A DIET PREFERENCES OF ROUND GOBY (NEOGOBIUS MELANOSTOMUS) NEAR SLEEPING BEAR DUNES NATIONAL LAKESHORE

5/18/2015  |   14:15 - 14:30   |  101A

DIET PREFERENCES OF ROUND GOBY (NEOGOBIUS MELANOSTOMUS) NEAR SLEEPING BEAR DUNES NATIONAL LAKESHORE The invasive round goby (Neogobius melanostomous)has been hypothesized as a possible vector for Type-E botulism along with the nuisance alga Cladophora glomerata. The objective of this study was to identify interannual patterns in goby diets in areas with and without Cladophora. Samples were collected in Lake Michigan near Sleeping Bear Dunes National Lakeshore from 2012-2013. A total of 745 fish were captured using minnow traps, categorized into three size classes (<59mm; 60-99mm; >100mm), and processed for stomach content analysis. Microcrustacea (copepods, cladocerans, and ostracods) were important diet items for all size classes, comprising 43-90% of total gut contents. There was a trend towards higher taxonomic richness in all size classes in 2012 than in 2013. Schoener’s index revealed that there was high diet overlap (R0>0.77) between fish living in both habitat types. Preliminary results suggest that presence of Cladophora mats may not play a major role in goby feeding preferences.

Erica Johnson (POC,Primary Presenter), U.S. Geological Survey, Great Lakes Science Center, 1451 Green Road, Ann Arbor, Michigan 48105 United States, eljohnson@usgs.gov;


Taaja Tucker (Co-Presenter/Co-Author), CSS-Dynamac, 10301 Democracy Lane, Suite 300, Fairfax, Virginia 22030, United States, trtucker@usgs.gov;


Steven Farha (Co-Presenter/Co-Author), USGS - Great Lakes Science Center Hammond Bay Biological Station 11188 Ray Rd. Millersburg, MI 49759, sfarha@usgs.gov;


Paige Wigren (Co-Presenter/Co-Author), U.S. Geological Survey, Great Lakes Science Center, 1451 Green Road, Ann Arbor, Michigan 48105 United States, pwigren@usgs.gov;


Stephen Riley (Co-Presenter/Co-Author), U.S. Geological Survey, Great Lakes Science Center, 1451 Green Road, Ann Arbor, Michigan 48105 United States, sriley@usgs.gov;


14:30 - 14:45: / 101A HAS THE BENTHIC MACROINVERTEBRATE COMMUNITY OF SOUTHWESTERN LAKE ONTARIO CHANGED SINCE THE ROUND GOBY INVASION?-1983 TO 2014

5/18/2015  |   14:30 - 14:45   |  101A

HAS THE BENTHIC MACROINVERTEBRATE COMMUNITY OF SOUTHWESTERN LAKE ONTARIO CHANGED SINCE THE ROUND GOBY INVASION?-1983 TO 2014 In Lake Ontario, the establishment of dreissenid mussels (Dreissena spp.) in the late 1980s, the amphipod Echinogammarus ischnus in the mid-1990s, and the round goby (Neogobius melanostomus) in the mid-2000s has engendered mixed responses, long- and short-term, in benthic macroinvertebrate communities. We sampled and quantified benthic macroinvertebrate abundances at a natural cobble site and artificial reef located in southwestern Lake Ontario near Olcott, New York, where benthic macroinvertebrate abundances were documented in 1983, 1991-1992, and 1999-2000. We found a significant difference in benthic community composition among year groups (Analysis of Similarities, R = 0.854, p= 0.01). We observed a shift in dominant taxa at both study sites, as oligochaetes and chironomids increased by more than 50% from 2000 to 2014, gastropods decreased by >50%, and E. ischnus became the dominant amphipod for the first time in 2014. Our findings suggest that the combined presence of round gobies and dreissenids has shifted the macroinvertebrate community structure from one dominated by gastropods and crustaceans, particularly the amphipod, E. ischnus, to one dominated by small, soft-bodied taxa (e.g, oligochaetes and chironomids).

Katherine Bailey (Primary Presenter/Author), The College at Brockport, State University of New York, kbail3@u.brockport.edu;


James Haynes (Co-Presenter/Co-Author), The College at Brockport, State University of New York, jhaynes@brockport.edu;