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Harbour Explorer

Invasive Species

This length of the Hamilton Waterfront Trail is a particularly great location to spot a couple of Hamilton Harbour’s invasive species. Take a seat on one of the trail’s benches or stop and rest by the boat launch gazebo and you might notice large grey and orange fish swimming in schools. These fish are exactly what they look like – goldfish! However, unlike your pet goldfish, these fish are not to be fed.

Goldfish are an invasive species, originally brought over from Asia in the 1800s. Today, however, they are released into the harbour and its watershed by their owners who, for one reason or another, can no longer care for them. Goldfish are quite detrimental and have similar effects upon the ecosystem as their relative, the invasive common carp. Goldfish compete with other species for resources, interfere with reproduction of native fish and wildlife species, uproot aquatic plants and in the process, release sediments, clouding the water and preventing the growth of new vegetation.

Along the trail you might also spot another one of the Harbour’s most conspicuous alien residents, the mute swan. Identified by their white plumage and orange beaks, these birds are native to Europe and Asia, a less vocal but far more aggressive species compared to their North American counterpart, the trumpeter swan. Mute Swans are particularly aggressive during the mating season. At this time they occupy large territories and displace native marsh birds.