Sydenham River (Lake St. Clair)

{{About|the Ontario river that flows into Lake St. Clair|the Ontario river which flows into Georgian Bay|Sydenham River (Lake Huron)}}

The Sydenham River is a river in Chatham-Kent, Lambton County and Middlesex County in southwestern Ontario, Canada, flowing southwest from its source west of London, Ontario and emptying into Lake Saint Clair. The length of the river is {{convert|165|km|mi}} and it drains a watershed of approximately {{convert|2700|km2|mi2}}, making it one of the largest river flowing into the St.Clair on the Canadian side.{{cite web |title=St. Clair River |url=https://friendsofstclair.ca/our-river/ |website=Friends of the St. Clair River |publisher=Friends of the St. Clair River |access-date=16 March 2025}} The river flows through the towns of Strathroy and Wallaceburg. It was named after Lord Sydenham, governor of Canada from 1839 to 1841.

Unusual concretions, composed of calcite, can be found near this river. These are known as "kettles" because they resemble the bottom of a large kettle.

The river has been identified as a key biodiversity area.

Fish species

Because this river flows through a large agricultural area, its waters collect silt and fertilizer runoff. In spite of this, the river provides habitat for 80 fish species and 34 species of freshwater mussels; these include:

;Nine mussel species considered as "endangered" nationally

;Two fish species and one turtle subspecies considered to be "threatened"

The Northern madtom (Noturus stigmosus), once found in the river, is considered to be "likely extirpated".

See also

References

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{{cite news

| url = https://www.cbc.ca/news/canada/windsor/southwestern-ont-home-to-globally-important-freshwater-biodiversity-areas-new-report-1.4659964

| title = Southwestern Ont. home to globally-important freshwater biodiversity areas: new report

| work = CBC News

| author = Jonathon Pinto

| date = 2018-05-11

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| access-date = 2018-09-09

| quote = The report by the International Union for Conservation of Nature lists Canada's "freshwater key biodiversity areas" or KBAs. Of the four KBAs in Ontario, three are in the southwestern part of the province: eastern Lake St. Clair, the east Sydenham River, and the Ausable River.

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{{cite news

| url = https://www.sarniathisweek.com/2018/03/13/sydenhams-north-branch-has-remained-largely-unobserved-until-now/wcm/da37cc3f-3d05-49a7-56e6-3876f5665897

| title = Sydenham's north branch has remained largely unobserved until now

| work = Sarnia this week

| author = Melissa Schilz

| date = 2018-03-13

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| quote = The discovery of the new species could mean the existence of other unknown species in that part of the Sydenham, he said. In 2017, researchers identified 20 different species of mussels in the river.

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{{cite web

| url = https://www.registrelep-sararegistry.gc.ca/default.asp?lang=En&n=16C0DCC1-1

| title = COSEWIC Assessment and Status Report on the Northern Madtom Noturus stigmosus in Canada – 2012

| work = Species at risk public registry

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| access-date = 2018-09-09

| quote = In Canada, the Northern Madtom is known only from the Detroit River, St. Clair River, Lake St. Clair, the Thames River and the Sydenham River (Figure 3).

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