After two decades of not being seen at the aptly named Fish Creek, one at-risk fish species has re-emerged.
The Black Redhorse, a species of sucker, was designated at-risk in Canada in 1988, only found in a few rivers across the nation, the nearby Thames River and Grand River and their tributaries in particular.
However, being vulnerable to pollution, climate change, severe weather, invasive species, human intrusion, and dams and barriers, the Black Redhorse began to disappear from excessively silty aquatic environments.
Its re-emergence at Fish Creek, a small creek just outside the Perth South village of Prospect Hill, signals that local conservation efforts at the Upper Thames River Conservation Authority (UTRCA) are working.
Tatianna Lozier, UTRCA’s stewardship services coordinator, shared in an announcement post on the UTRCA website, that in the last twenty years the Clean Water Program, a rural water quality initiative, has funded 85 projects in Fish Creek.
“This figure is just a fraction of the various stewardship initiatives occurring in the watershed beyond our program’s scope,” Lozier wrote. “Over the last few years, there has been an increase in requests for stewardship support in Fish Creek, a trend that we are happy to see. Hope remains for the long-term improvement of the subwatershed’s health.”
Cathy Quinlain, terrestrial biologist with the conservation authority, told StratfordToday that it is an exciting find.
“The more you look, the more you will find,” Quinlain said. “It's a two-edged sword. You're looking for the good stuff, but you're also prepared to see the not-so-good stuff.”
That includes the designated invasive species, an ever-expanding list of species that pose great risk to Ontario’s many ecosystems.
That list is expanding in the new year. Ten species and four groups of similar species are being added.
Quinlain said that the new additions are a preventative approach to these species, letting the public and different conservation groups know that these species are potentially a threat.
She clarified that with such a large watershed from London to Stratford to Woodstock, covering 3,430 square kilometres, it is hard to tell how prevalent these species are in the region.
Additionally, without funding to help combat the spread of invasive species in the environment, managing these species across such a large area is very difficult.
“The fish in the Thames River is one of the most diverse fisheries in Canada,” Quinlain said. “We want to keep it that way and keeping out anything invasive is a priority.”
The following species and groups will be prohibited in Ontario effective Jan. 1.
Ide (fish)
- Potential impacts: introduce parasites, virus and disease transmission, and compete with native fishes.
Eastern and Western Mosquito Fishes (fish)
- Potential impacts: outcompete native fish species for food and habitat through aggressive feeding of zooplankton, eggs and larvae, leading to the loss of biodiversity and potential loss of some native species in Ontario.
Red Shiner (fish)
- Potential impacts: reduce native fish populations through predation on eggs and larvae, genetic impacts through hybridization, and introduction of parasites.
Oxygen Weed (aquatic plant)
- Potential impacts: dense colonies outcompete native vegetation, adversely affect water quality and impede recreational activities such as boating and swimming.
Nutria (mammal)
- Potential impacts: burrowing and foraging behaviour impacts agricultural areas and increases flooding risks, spread parasites and disease to humans, pets and livestock, and can destroy coastal wetlands.
Genus Salvinia (Watermoss – aquatic plant)
- Potential impacts: dense colonies outcompete native vegetation, adversely affect water quality and impede recreational activities such as boating and swimming.
Genus Procambarus and Genus Pacifastacus (Crayfish)
- Potential impacts: compete with native crayfish and fish species for food and shelter.
The following species and group will now be restricted effective Jan. 1, 2024:
Eurasian Water-milfoil (aquatic plant)
- Potential impacts: outcompete native vegetation, adversely affect water quality, impede recreational activities and create habitat for mosquitoes.
Floating Primrose-willow (aquatic plant)
- Potential impacts: dense colonies outcompete native vegetation, adversely affect water quality, and impedes recreational activities such as boating and swimming.
Flowering-rush (aquatic plant)
- Potential impacts: can displace native riparian vegetation, forms dense stands which impact industrial and recreational uses of shallow waters, and reduces habitat of native fish and increases habitat for invasive fish.
Tree-of-heaven (terrestrial plant)
- Potential impacts: changes chemical and microbial activity in soils, reduces soil nutrients, displace native plant species, associated with several fungal pathogens and the preferred host to the spotted lanternfly (Lycorma delicatula).
Genus Azolla (Water Ferns – aquatic plant)
- Potential impacts: dense colonies outcompete native vegetation, adversely affect water quality, impedes recreational activities such as boating and swimming, and negatively affect wild rice populations.
