Welcome back to my PEI Habitat Highlights series. You can find previous editions – including Grey Dunes, Krummholtz Forest, Peat Bogs, and Salt Marshes – in the ‘Habitats and Ecology’ section of this blog. Today’s habitat: lakes!
The Island’s settlers were fairly loose with the term “lake” as a place name. We have a dozen named lakes, but few of them truly are. Some, such as South Lake, are really barachois: an area of open water behind a sand dune or spit. Others, such as O’Keefe’s Lake, are ponds. Although ‘lake’ and ‘pond’ are often used interchangeably, a true lake is deep enough that sunlight doesn’t reach all the way to the bottom.
One of the Island’s few true lakes is Portage Lake in Prince County, visible from Route 2 in Portage. It’s only about 1.5 km as the crow flies from Portage Lake north over land to Foxley Bay, hence the name: it was once a portage route linking the Northumberland Strait and Gulf of St. Lawrence. Don’t mistake the nearby pond with mowed grass and residences around it for Portage Lake. That’s a human-made pond that was once an excavation pit; Portage Lake is a few hundred metres further west.
The origin of PEI’s true lakes is often closely linked with that of our peat bogs, and Portage Lake is indeed surrounded by a bog. At the end of the last Ice Age some 12,500 years, what is now Portage Lake (and its associated bog) would have been a deep hole of barren rock. Rain and glacial meltwaters filled the hole, and algae first colonized the shallower edges before Sphagnum mosses and higher plants moved in. Over thousands of years, the mosses and plants filled all but the deepest part of the hole, leaving Portage Lake as an area of deep open water. Local legend says Portage Lake is bottomless. I knew someone who went down with scuba gear and reported it as very deep and very dark, with eerie strands of peat moss obscuring the bottom. I don’t think he actually connected with the bottom so maybe the legend is true! Perhaps it’s no surprise that another legend claims treasure is buried there. At the south end of the lake is a canal, which I expect was hand dug given how wet the area is. According to aerial photos, it wasn’t there in 1935 but was by 1958. (You can see it on Google Earth). In the 1980s, researchers collected fossil pollen from deep in the surrounding bog, helping reconstruct what PEI’s vegetation looked like after the last Ice Age. Next time you’re passing through Portage, take a moment to appreciate the unique ecological area that is Prince County’s only lake – an important part of PEI untamed!