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Editorial Cartoon by Graeme MacKay, The Hamilton Spectator – Saturday September 8, 2018

Scientists urging people to stop dumping aquarium and market fish into Hamilton Harbour

Harbour scientists say they have been finding some strange new creatures in Hamilton Harbour this summer, suggesting people are dumping aquarium and fish market species into the waters.

“We’ve seen some fish that really should not be there and it’s really a sign of people purposefully and irresponsibly and illegally releasing fish into Hamilton Harbour,” said Becky Cudmore, senior science adviser on aquatic invasive species with Fisheries and Oceans Canada.

Among the findings are four tilapia fish and a type of aquarium catfish. This is on top of an established population of goldfish, the outcome of untold numbers of people emptying their aquarium fish into the bay and Cootes Paradise.

“What we are seeing with goldfish is something we don’t want to see happening with other species,” she said.

She believes the tilapia, a non-native species originally from the Middle East and Africa, were bought at a fish market and then released into the harbour in a misguided effort to save the fish from being eaten.

“It’s not fair to the fish because they are not meant to be in that water,” said Cudmore. She urged people with unwanted aquarium fish to take the fish to pet rescue centres or back to the store where they bought them.

She expects tilapia in the harbour will die out over the winter because the species prefers tropical environments. But some could survive by using warm water effluent from Hamilton steel mills as an overwintering haven.

Tys Theijsmeijer, the head of natural lands for the Royal Botanical Gardens, says as well as adversely affecting native species, introduced species can bring new diseases to the ecosystem. (Source: Hamilton Spectator)