The lake has been plagued with a number of invasive species, including zebra and quagga mussels, the goby and the grass carp. One estimate was that there have been 180 invasive species in the Great Lakes, some having traveled in ballast water in international ships. Zebra mussels and gobies have been credited with the increased population and size of smallmouth bass in Lake Erie. In 2008 there were concerns that the "newest invader swarming in the Great Lakes", which was the bloody-red shrimp, might harm fish populations and promote algae blooms.