River Threat: the Round Goby
By Tristan Philips
Waking up to go fishing as the sun rises over Deer Island is one of my favorite things to do. I would pack up my gear and head out on the boat with my father. We would head to our favorite Smallmouth Bass fishing spot and drop anchor. One particular morning when I was very young, I vaguely remember my dad complaining about catching some sort of small fish he’s never seen in the St. Lawrence River before. Cast after cast we were catching the same pesky critter over, and over,- the Round Goby.
Round Goby or Neogobius melanostomus is a euryhaline bottom dwelling goby native to the Black and Caspian Sea. The average size of this fish is 5-6 inches but can grow to just under a foot. The first goby captured in the St. Lawrence River was near Quebec,Canada in 1997. They are a non- native invasive species that were introduced through commercial transporting of goods. When a freighter from the Black or Caspian Sea would dump its bilge into the St. Lawrence River hundreds if not thousands of these fish would be accidentally introduced to its waters.
Round Gobies pose many threats to native species in the St. Lawrence River. The number of native species have declined in areas where the round Goby’s flourish. This species preys on native darters, sculpins, and logperch. Round Gobies also have been found to have a significant overlap in diet preferences with many native fish species. They compete with full grown darters, logperch, and madtoms for macro invertebrates. Gobies also compete with Mottled sculpins for spawning sites(USGS). In scientific studies Gobies were found to chase Mottled sculpins out of their spawning sight and not allow them to return.Sometimes the only fish that commercial anglers can catch are round gobies. Gobies also eat the roe of smallmouth bass, consuming up to 4,000 eggs within 15 minutes. It is also suspected that round gobies spread Avian botulism, botulism infected birds have been found to eat more round gobies than uninfected birds.
Like some invasive species Round Gobies do have some positive effects on their environment. Gobies are the only natural predators of the invasive and harmful zebra mussel. Water snakes also have experienced a population boom since the introduction of the round Goby. A water snakes main source of food is now the Goby. Large/Smallmouth bass, Walleye, and Yellow perch also feed on the round gobies which provide an abundant food source for the sport fishes.
There have been many efforts to control the spread and growth of the flourishing round Gobies in the St. Lawrence River. Native Burbot are being looked into for the control of Round Gobies for the voracious eating habits. A risky way to control the gobies is to increase CO2 concentrations of waters that are heavily populated with gobies. This is very difficult to do in large bodies of water as other fish would be affected so it would only be useful in a small bay or harbor. Another intuitive way to control the spread of Gobies is to permit electrical barriers as gobies will not swim through electrical barriers in tank experiments.
Fishing in the St. Lawrence today isn’t the same as it used to be 100 years ago. When I caught my first Goby I thought I had an alien at the end of my line. I figured after all the years of catching these critters that they were just a natural part of the St. Lawrence ecosystem. It wasn’t until just recently that I noticed that they had spread everywhere in the river, in different depths and in different temperatures. If just a casual fisherman like myself can notice this becoming an issue, what will it take to protect the waters from this voracious predator?
[Photo, Ohio Sea Grant: Goby, by Kristen Stamford licensed by CC BY-NC 2.0]
By Tristan Philips
Waking up to go fishing as the sun rises over Deer Island is one of my favorite things to do. I would pack up my gear and head out on the boat with my father. We would head to our favorite Smallmouth Bass fishing spot and drop anchor. One particular morning when I was very young, I vaguely remember my dad complaining about catching some sort of small fish he’s never seen in the St. Lawrence River before. Cast after cast we were catching the same pesky critter over, and over,- the Round Goby.
Round Goby or Neogobius melanostomus is a euryhaline bottom dwelling goby native to the Black and Caspian Sea. The average size of this fish is 5-6 inches but can grow to just under a foot. The first goby captured in the St. Lawrence River was near Quebec,Canada in 1997. They are a non- native invasive species that were introduced through commercial transporting of goods. When a freighter from the Black or Caspian Sea would dump its bilge into the St. Lawrence River hundreds if not thousands of these fish would be accidentally introduced to its waters.
Round Gobies pose many threats to native species in the St. Lawrence River. The number of native species have declined in areas where the round Goby’s flourish. This species preys on native darters, sculpins, and logperch. Round Gobies also have been found to have a significant overlap in diet preferences with many native fish species. They compete with full grown darters, logperch, and madtoms for macro invertebrates. Gobies also compete with Mottled sculpins for spawning sites(USGS). In scientific studies Gobies were found to chase Mottled sculpins out of their spawning sight and not allow them to return.Sometimes the only fish that commercial anglers can catch are round gobies. Gobies also eat the roe of smallmouth bass, consuming up to 4,000 eggs within 15 minutes. It is also suspected that round gobies spread Avian botulism, botulism infected birds have been found to eat more round gobies than uninfected birds.
Like some invasive species Round Gobies do have some positive effects on their environment. Gobies are the only natural predators of the invasive and harmful zebra mussel. Water snakes also have experienced a population boom since the introduction of the round Goby. A water snakes main source of food is now the Goby. Large/Smallmouth bass, Walleye, and Yellow perch also feed on the round gobies which provide an abundant food source for the sport fishes.
There have been many efforts to control the spread and growth of the flourishing round Gobies in the St. Lawrence River. Native Burbot are being looked into for the control of Round Gobies for the voracious eating habits. A risky way to control the gobies is to increase CO2 concentrations of waters that are heavily populated with gobies. This is very difficult to do in large bodies of water as other fish would be affected so it would only be useful in a small bay or harbor. Another intuitive way to control the spread of Gobies is to permit electrical barriers as gobies will not swim through electrical barriers in tank experiments.
Fishing in the St. Lawrence today isn’t the same as it used to be 100 years ago. When I caught my first Goby I thought I had an alien at the end of my line. I figured after all the years of catching these critters that they were just a natural part of the St. Lawrence ecosystem. It wasn’t until just recently that I noticed that they had spread everywhere in the river, in different depths and in different temperatures. If just a casual fisherman like myself can notice this becoming an issue, what will it take to protect the waters from this voracious predator?
[Photo, Ohio Sea Grant: Goby, by Kristen Stamford licensed by CC BY-NC 2.0]