The round goby, an aggressive, non-native species of fish introduced to the Great Lakes in the early 1990s by the ballast water of ocean-going vessels, has invaded the state’s tributaries of Lake Erie, according to Pennsylvania Sea Grant-supported research by a Gannon University biologist.
After collecting samples from six tributaries that feed Lake Erie, Dr. Edward C. Phillips found that the goby population was most dense in Elk Creek, where just over 137 gobies were collected per hour of electrofishing. Where present, gobies made up 17.1 percent of the fish present in Elk Creek, and were found as far as 1.4 miles from the mouth of the creek.
Round gobies had their second greatest density in Twenty Mile Creek, where almost 104 round gobies were collected in an hour. Gobies made up 30.4 percent of the fish collected, but were found no farther than four-tenths of a mile upstream, where a waterfall blocks further invasion.
The third greatest density of round gobies was found in Walnut Creek. Gobies made up 12.7 percent of the fish collected, and were found as far as three-tenths of a mile upstream. Gobies comprised only 1.5 percent of the fish found in Sixteen Mile Creek, primarily because fish were collected only from a pool just above the mouth.
No gobies were found in Twelve Mile Creek or Conneaut Creek. And no round gobies were collected in upstream areas of the sampled streams, indicating that, thus far, there has been no bait-bucket transfer of the fish.