The round goby, or Neogobius Melanostomus, is a small fish that was introduced to the Great Lakes in 1990. Since their arrival, many ecological changes have occurred, including a change in the food chain with their consumption of dreissenid mussels. This is influencing the benthic macroinvertebrate abundance, through predation, and could cause a collapse in the energy flow (food chain). Methods for evaluating the density and size of round gobies are lacking, preventing the true quantification of
the effects of round gobies on invaded ecosystems. Therefore, in Lake Erie, a team from the Ontario Ministry of Natural Resources evaluated different sampling methods of the round goby, and then applied the best method to estimate the distribution and density of the species. It was found that a combination of angling and bottom trawling were the most effective methods of sampling. With these methods, an estimated 9.9 billion round gobies in Lake Erie in 2002 were found.
T.B. Johnson, M. Allen, L.D. Corkum and V. A. Lee. Comparison of Methods Needed to Estimate Population Size of Round Gobies (Neogobius melanostomus) in Western Lake Erie. Journal of Great Lakes Research. Volume 31, Issue 1. 2005. Pages 78-86.