Sandusky, OH A small invasive fish is competing directly against an important native fish species for food in Lake Erie, according to new Ohio Sea Grant research. Invasive round gobies feed at roughly the same time of day as native smallmouth bass, allowing gobies to greatly impact bass, the lake’s third most popular sport fish.
Dr. Chris Winslow, of Kutztown University and research students at Ohio State University’s Stone Laboratory, used results from SCUBA diving, videotaping, and trawling to determine that round gobies feed from early morning through early evening, which directly overlaps with smallmouth bass activity. This causes the goby to have a large impact on juvenile smallmouth bass feeding behavior.
"With the smallmouth bass fishery bringing in $40 million each year, we needed to know more about these species and how they interact with each other in order to manage them successfully," Winslow states.
This project builds on Winslow’s previous Sea Grant research, which showed that gobies push young smallmouth bass off the lake floor, forcing the native fish to eat smaller organisms. He found that this change in diet caused smallmouth bass to grow 1.5 to 2.5 more slowly than if gobies were not present.
Gobies eat smallmouth bass eggs and out-compete young smallmouth bass for food. The tables turn for smallmouth bass once they reach approximately two inches in length. At this size, smallmouth bass begin to eat gobies and smallmouth bass that eat gobies grow twice as fast as those that aren’t eating gobies.
"The positive and negative interactions between round gobies and smallmouth bass are complex," Winslow says. "If smallmouth bass grow to fish-eating size, then great, Lake Erie becomes home to large smallmouth bass. But if competition with round gobies slows juvenile smallmouth growth, then the smallmouth bass population may decline."
To learn more about this Ohio Sea Grant-funded research, visit http://ohioseagrant.osu.edu/_documents/twineline/v32i3.pdf .
Chris Winslow, Kutztown University of Pennsylvania, Assistant Professor, Biology Department: 484-646-5861, firstname.lastname@example.org .