PLANARIANS - LAKE ERIE - CENTRAL BASIN - AVON POINT

Above is a photo of an animal that belongs to the Phylum Platyhelminthes – they are commonly known as planarians or flatworms. These fascinating animals are not worms, as their common name implies, worms belong to the Phylum Annelid. Planarians are the most primitive of the bilateral animals. These animals are small, from 4 to 8 mm. long but they are voracious hunters. The above species is new to the area. Several years ago enormous numbers of a different species of planarians of the genus Dugesia were found on the reef. They all disappeared after the arrival of the rounded gobies. This year (2000) I am finding these animals on the rocks, though in nowhere near the number that I found the old species. In 1994 and 1995 I estimated that by July and August there could be found 300 to 600 hundred planarians per square meter on the rocky areas of the reef, by 1998 the animal had all but completely disappeared. This new species is just beginning to inhabit the reef.

These animals have an aversion to light and live on the underside of rocks. Their “eyes” a rudimentary, they are more like light detectors then organs for vision. They move by beating an enormous number of cilia (hairs) on their underside. And their “mouth” is a tube (proboscis) found about midway on their underside.

I find it interesting that if you left a planarian alone, over time it would get old and die. But if you got hold of an old planarian and chopped it up into pieces each piece would grow into a new animal and that new animal would be young. If only this would work for me.