Giant goldfish, from pets to invasive species in Canadian waters | Ecology | magazine

leave a loose goldfish in wild water It is not a simple leap towards freedom. It has dire consequences, and these bloated specimens of fish native to East Asia are a case in point.

They were once pets, but Released in (man-made) rainwater drainage basins in CanadaAnd now they are a big problem. This species is able to continue to grow throughout its life, especially if the conditions are favorable for it.

It is a myth that goldfish only grow to the size of an aquarium. And it is that such a small space causes stress to the animal, and stops its growth, because This creature is able to secrete hormones to regulate its size. But in open spaces and with enough food, as in Canadian waters, it has no reason to control itself.

Scientists from Canadian Fisheries and Oceans have been tracking the movements of invasive goldfish for months, using a device that makes sounds once it sticks to the fish’s abdomen.

In October 2021, University of Toronto Scarborough biology professor Nick Mandrake discovered More than 20,000 goldfish live in a man-made pond outside OntarioHarsh environment, with shallow waters, extremely low oxygen levels and temperatures above 30°C in summer.

Well, goldfish live there, and they multiply very quickly.

This worries researchers. As oxygen levels in the water drop due to climate change, These fish will have an advantage over other native speciesAnd at some point it could become a monoculture. Mandrake asks, “Are we making super invaders?”

• Unlike other fish, Dorado can survive in waters polluted with toxic blue-green algaeIt is even believed that it helps in their reproduction.
• What is more, gluttonous goldfish. A large school of them can quickly destroy aquatic habitats, eliminating plants.
• Also spread in the port Hamilton (Lake Ontario)and invaded the spawning sites of native species such as the European pike, inundating the water with their detritus.
• Also, while eating, it stirs up sediment, which reduces the levels of sunlight that aquatic plants need to thrive.

This is the greatest fear of scientists The future reaches the Great Lakes – Superior, Michigan, Huron, Erie and Ontario, on the Canada-US border – if their numbers weren’t small. (me)