Globetrotting bottom dweller hitches lifts in cargo ships
This entry into the Cabinet of Freshwater Curiosities isn’t endangered – in fact it is actively considered an invasive pest. Nor is it what you might term particularly beautiful – a small, bottom feeding fish with big, protruding eyes and stubby fins. However, despite this, the round goby is one of the world’s most curious, adaptable and plain weird fish.
Native to Eastern Europe and west Asia, the round goby is a remarkably adaptable little fish, colonising waterways in North America by hitching lifts in the ballast water of cargo ships. Reaching a maximum size of around 25cm, and mottled in shades of brown, grey and green, round gobies are extremely successful spawners. Females lay as many as 6 clutches of highly adhesive eggs during the summer breeding season, which stick to stones, shells and occasionally cargo ships!
It is through this transatlantic trade route that the hardy little goby has colonised North American waterways. Adult gobies are astonishingly resilient – withstanding water with extremely low oxygen content where other fish cannot live. This adaptation, coupled with the goby’s aggressive behaviour means that it can outcompete native fishes for food and nests.
In the American Great Lakes, the goby is proving extremely successful at outcompeting native fish like the sculpin and logperch. Despite this, the round goby’s invasion has had unexpected positive consequences for its predators in the Great Lakes, with the largemouth bass, walleye and the endangered Lake Erie watersnake all benefitting from increased food supplies.
Find out more:
- Round goby at Fish base
- US Department of Agriculture Invasive Species factsheet
- US Great Lakes Science Centre information page
- Science Daily on the round goby’s invasive abilities
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