For nearly 20 years, scientists have been conducting an artificial reproduction program for the copper redhorse in an attempt to prevent the disappearance of this species, which only exists in Quebec. But their efforts are hampered by the lack of protection of the habitat essential to the survival of this fish, which is increasingly threatened by human activity.
The facilities are seemingly quite modest, under a section of the structure of the Saint-Ours dam, on the bank of the Richelieu River. Yet it is here that much of the copper redhorse’s future is at stake, thanks to the work of the team led by biologist Nathalie Vachon, from the Ministry of the Environment, the Fight Against Climate Change, the Wildlife and Parks (MELCCFP).
The choice of site is no coincidence, since this endangered fish goes up the river in June to spawn just downstream of the dam, or else to try to cross it to reach the only other known spawning ground (place where the fish lay), in the archipelago of the Chambly rapids.
It is therefore here that biologists capture adult redhorses, with a net or thanks to the migratory pass of the dam. Their objective: to collect eggs from females and milt from males for the artificial reproduction program set up in 2004 to prevent the disappearance of this endemic species in Quebec.
The operation follows a scientific protocol that includes brief anesthesia of each individual selected for the program, evaluation of milt quality using a microscope, and use of milt from several males (sometimes using to cryopreservation) in order to diversify the genetics of the larvae that will be born at the Baldwin-Coaticook fish hatchery, before being seeded at the fry stage later in the year.
Each adult, who reaches sexual maturity only around the age of 10, is also provided with a microchip which allows them to be identified, then transported by truck before being released a few kilometers upstream.
Mme Vachon is at the heart of this operation, which lasts barely a few days, at the height of the species’ migration. And this year, “the results are very positive,” she said at the end of the exercise. In all, just over thirty individuals were captured, and all but one were captured for the first time. Over time, she points out that the redhorses resulting from the work have become breeders, which means that they can now contribute to the survival of the species.
It must be said that the copper redhorse is so threatened that every fish counts. “The population was assessed in 2014 at a few hundred or even a few thousand individuals, but we are talking about an estimate here. It is impossible to specify the total”, summarizes Nathalie Vachon.
Threatened habitat
Over the past 19 years, the breeding program has been carried out 13 times, resulting in the stocking of 438,000 young-of-the-year and 15,200 one-year-old individuals in the Richelieu River.
However, these fish are found in a habitat that has been restricted over time and which is threatened by human activity, summarizes the director general of the Society for Nature and Parks of Quebec, Alain Branchaud. “We are really talking about an accumulation of stress that is detrimental to the species”, underlines the biologist, who worked on the development of the artificial reproduction program for the copper redhorse.
The Richelieu River notably crosses a densely populated territory subject to intensive agricultural activity, recalls retired agronomist Louis Lahaie, president and CEO of Action Eau Richelieu. Result: the quality of the water suffers from the drainage of phosphorus, which stimulates the growth of algae, and from the presence of pesticides. A government study has already confirmed the presence of around fifteen pesticides in the waters of this river.
The river is also very popular with boaters. However, this navigation promotes the erosion of the banks and the loss of aquatic grass beds, which are essential to the copper redhorse, specifies the MELCCFP. “Boating is very intensive, so we end up with a constant mixing of water and sediment. The larvae have little chance of survival in such an environment,” laments Alain Branchaud. According to him, it would be important to impose stricter regulations on traffic and speed in areas important to the species, which are already well known.
In the meantime, the director general of the Comité de concertation et de valorisation du bassin de la rivière Richelieu, Sylvain Lapointe, points out for his part that the organization is trying to “raise awareness” among citizens who choose, for example, to go picnicking. on islands located at the heart of a spawning ground for the species. Quebec and Ottawa, for their part, claim to put forward several measures to try to avoid the extinction of the species, including a project to protect an important sector of the Richelieu River, which remains to be implemented.
Port of Montreal expansion project
At the same time, the federal government must decide whether to authorize the destruction of copper redhorse habitat to build the Port of Montreal expansion project at Contrecoeur. The project will result in the destruction of portions of the species’ “critical habitat”, which has been duly protected since 2021 under Canada’s Species at Risk Act (SARA). The Copper Redhorse is classified as “endangered”, which is the most critical status before that of “extinct” species.
Is this new industrial infrastructure compatible with the protection of the copper redhorse? Fisheries and Oceans Canada “continues to work with the proponent as part of the ongoing regulatory review process,” responds the department.
The Legault government, which had opposite protection of critical habitat for the copper redhorse, has already pledged $130 million for the project, while the Trudeau government has already pledged $300 million.
Alain Branchaud is however formal: if Ottawa gives the green light, legal action will follow, to enforce the provisions of the SARA. “It is a unique species in Quebec, which means that it is entirely under our responsibility. We must have the courage to do what is necessary to save her, and it is one minute to midnight. »