STATE OF LAKE SUPERIOR IN 2017: AQUATIC
NUISANCE SPECIES34
Jared T. Myers35, Michael J. Seider, Mark J. Brouder, Anett S. Trebitz,
and Joel C. Hoffman
The fish community objective (FCO) for aquatic nuisance species (Horns et
al. 2003) in Lake Superior is to
Prevent the introduction of any non-indigenous aquatic species
that is not currently established in Lake Superior; prevent or
delay the spread of non-indigenous aquatic species, where
feasible; and eliminate or reduce populations of non-indigenous
nuisance species, where feasible.
Complete prevention of new species introductions, along with containment
and reduction of non-native nuisance species that are already present, is a
challenging but appropriate goal for Lake Superior. To evaluate the
effectiveness of the current regulatory framework for aquatic nuisance
species, federal, state, provincial, and tribal natural-resource agencies
worked together to implement non-native-species surveillance programs at
eight locations. These assessment programs were modeled after the approach
developed by Trebitz et al. (2009) and Hoffman et al. (2011, 2016) and
34Complete publication including maps of place names, abstract, other chapters, scientific
fish names, and references is available at
http://www.glfc.org/pubs/SpecialPubs/Sp21 02.pdf.
J.T. Myers, M.J. Seider, and M.J. Brouder. U.S. Fish and Wildlife Service, Ashland
Fish and Wildlife Conservation Office, 2800 Lakeshore Drive East, Ashland, WI 54806,
USA.
A.S. Trebitz and J.C. Hoffman. U.S. Environmental Protection Agency, Center for
Computational Toxicology and Ecology, Great Lakes Toxicology and Ecology Division,
6201 Congdon Boulevard, Duluth, MN 55804, USA.
^Corresponding author (e-mail: iared mvers@fws.gov'l.
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involve an adaptive cycle of assessment, refinement, and implementation
that uses performance measures to improve detection probability. Taxa
accumulation curves and randomization analyses have been the primary
tools for evaluating if gear allocation, sample distribution, and overall
sampling effort are appropriate for the location of interest. Non-native-
species surveillance surveys have typically relied on the deployment of
traditional sampling gears and taxonomic identification using physical
characteristics. The new approach, however, uses DNA-based identification
approaches, such as metabarcoding of ichthyoplankton and zooplankton
samples and eDNA metabarcoding for fish detection to improve survey
accuracy in the future. These techniques have been the subject of
experimentation in the Port of Duluth-Superior (metabarcoding for
ichthyoplankton samples and fish detection) and Apostle Islands
(metabarcoding of zooplankton samples) (Fig. 45). Continuing to adhere to
an adaptive approach for early detection will ensure the delivery of a
surveillance program that is responsive, transparent, efficient, and effective.
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Each of the 18 non-native fish species known to exist in Lake Superior was
observed at least once during the current 5-year reporting period (2012-
2016), but no new non-native fish species were found. One particularly
noteworthy observation was the reappearance of White Bass in the Port of
Duluth-Superior. This species had not been documented since the 1980s, yet
both adult and juvenile specimens of 96-362 mm total length from the 2010,
2011, and 2014 year-classes were collected in 2015 and 2016. The
invertebrate banded mystery snail (Viviparus georgianus) was collected in
2014 while bottom trawling in the upper St. Marys River. The banded
mystery snail is native to the southeastern part of the U.S. and the
Mississippi River system but is considered invasive in the Great Lakes. The
non-native faucet snail (Bithynia tentaculata), first detected in the
Chequamegon Bay area in 2010, was found to be established and abundant
in the Port of Duluth-Superior in 2012 and 2013 (Trebitz et al. 2015). Lastly,
zebra mussels (Dreissena polymorpha) and quagga mussels (I), bugensis)
were first detected in the Port of Duluth-Superior in 1989 and 2005,
respectively (Griffiths et al. 1991; Grigorovich et al. 2008). These mussels
have likely expanded their range to the Apostle Islands, as zebra mussels
were found on a shipwreck near Sand Island in 2015 and 2016, and quagga
mussels were found attached to commercial fishing gear near Madeline
Island in 2011 and throughout the reporting period. Given the evidence for a
new introduction (i.e., banded mystery snail), the spread of faucet snails and
zebra and quagga mussels, and the reemergence of White Bass, we argue the
FCO for aquatic nuisance species has not been met.
While there are a host of pathways by which new invaders could reach Lake
Superior, ballast water still poses the highest risk (O'Malia et al. 2018).
Progress has been made in the management of ballast from ocean-going
vessels, but domestic vessels operating within the Great Lakes still have a
high potential for spreading species within the region (Briski et al. 2012).
The principal cargos handled at Lake Superior ports are outbound iron ore,
coal, and grain; a scenario that leads to many of the inbound vessels arriving
with ballast water from the four lower Great Lakes. Lake Superior ports had
an average of 1,864 vessel visits per year and 40% of those were to the Port
of Duluth-Superior (Fig. 46), making it the largest bulk cargo port in the
Great Lakes. An average of 15 million metric tons of ballast water was
discharged annually at the Port of Duluth-Superior during the reporting
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period (Fig. 46), and 99.7% of the balance was from domestic vessels.
During the reporting period, there was a total of 143 million metric tons of
ballast water discharged into U.S. waters of Lake Superior, and 99.8% of the
ballast water was from domestic vessels (Fig. 47). Given the risk of
secondary infestations from domestic vessels, fishery managers should be
mindful of the species that are most likely to be introduced by monitoring
the status and distribution of non-native species in the lower Great Lakes.
Policy makers should seek to reduce the risk of new invasions by continuing
to implement the actions described within the Lake Superior Aquatic
Invasive Species Complete Prevention Plan (Lake Superior Binational
Program 2014).
Fig. 46. Number of visits and volume of ballast water discharged by commercial
shipping vessels at Lake Superior ports, 2012-2016. Horizontal black bars
represent the averages for the previous reporting period (2006-2011) (NBIC
2016; TBPA 2018).
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Fig. 47. Top 10 ranking of Lake Superior ballast water sources, as measured by
the last port visited by vessels discharging into U.S. waters of Lake Superior.
Cumulative discharge is the total volume for the current reporting period of
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