Bryozoans often appear in late summer and early fall.

Wander along the shores of freshwater lakes and ponds in late summer to possibly catch a glimpse of odd, jelly-like masses floating in the water.

Some of these may be several inches across — at first glance, they may be mistaken for pieces of plastic or a cluster of eggs.

Instead, these masses are freshwater bryozoans. To be more specific, it’s the Pectinatella magnifica, whose scientific name translates to “magnificent jelly.”

It’s native to the eastern United States but has been introduced to waterways in the West in recent decades by boats. While we do have some marine bryozoans along the coastline, this is our only freshwater species.

So what are bryozoans? Despite their sedentary lifestyle, they are tiny aquatic invertebrate animals. Individual bryozoans are called zooids, and they generally live in large colonies, attached to submerged logs, rocks, docks and other surfaces. They reach out into the water with their tentacles to grab minute particles of food.

The aptly-named magnificent bryozoan is especially large, and unlike other freshwater bryozoans, its colonies can create a jelly-like substrate to grow rather than having to individually cling to rocks.

As zooids reproduce, they create darker-colored patterns on the surface of the substrate that make them look rather like strange stones. A colony is often made of clones of a single parent zooid, all of which are genetically identical.

Bryozoans have an unusual third reproduction option. They can create cell masses called statoblasts. Once fully developed, these statoblasts can go into a period of dormancy that may last for years, only awakening when conditions have improved. The statoblasts can then develop into fully mature zooids to begin new colonies.

Because magnificent bryozoans are not a native species, their ecological impact is not yet fully understood, but they are a known parasite host. One parasite they host can cause kidney disease in salmonids, and given that Pacific coast salmonids are threatened already, removing a potential disease vector isn’t a bad idea.

Moreover, if these bryozoans proliferate near water pipes, they can cause clogging, and colonies near docks may be able to hitch a ride on boats that are not washed frequently enough to mitigate invasive species.

It’s safe to pick up a bryozoan colony — they aren’t harmful, though you’ll probably want to wash your hands after handling them due to the slime. When set on dry land far away from freshwater, they will die and decompose into the soil.

Marine bryozoans are more likely to be found when they wash up on the beach and are often mistaken for seaweed. The most commonly observed native species, especially on North Coast beaches, is the leather bryozoan. It’s named for its light brown hue and leathery appearance, though a closer look may show a hairy texture, too. Its shape may vary but is generally lobed and flat, and it’s common to find several masses together.

The red bryozoan is less common, usually found on rocks in tide pools. It is often mistaken for a species of algae, as it can form a red crust on the stones’ surface. Over time, colonies may grow larger and take on a tissue texture.

When the tide is in, an astute observer may see their tiny red tentacles emerge to capture food in the water.

Bryozoans may not be the flashiest of animals, but they are certainly unique. Whether walking along the beach or boating along freshwater corridors, keep your eyes open for these unusual, communal creatures.