So, is this a case of sci-fi come true? Rare freshwater jellyfish? Egg deposits of an aquatic creature? Actually, it’s none of the above. The blobs that are spotted this and every summer in local ponds and lakes are bryozoa – colonial invertebrates also commonly referred to as “moss animals.” Bryozoans come in many marine and fewer freshwater varieties; the species most often encountered in Southeastern freshwater is identified as Pectinatella magnifica.
They may be ugly, but colonial bryozoans are friends, not foes. Bryozoans function similarly to coral, with each colony containing thousands of tiny zooids, all filtering the water for food particles. Their presence may actually be an indicator of good water quality; Pectinatella magnifica is more likely to occur, and thrive, in fertile lakes and ponds, where there’s plenty of available organic matter upon which the zooids can feast.
The “jelly” that gives each colony a blob-like appearance is actually zooecium, a protective coating that holds the colony together. Neither the jelly nor its contents pose any health threat to humans, fish, or other animals. In fact, Pectinatella magnifica can be safely handled – no gloves required, except for the squeamish – and the colonies are often harmlessly consumed by wildlife.
The colonies die when the weather turns cold, but they do leave behind their tiny, egg-like statoblasts, which can survive the winter and start new colonies the following summer. Because the statoblasts can easily be carried by animals from one water body to another, the sudden appearance of colonies in a water body is not indicative of any change in the ecosystem. Depending on a variety of factors, colonies may come and go over the years.
