Freshwater Oddities

If you haven't had the opportunity to scuba dive, then you can only begin to imagine the adventure we experience while investigating the aquatic environment of our Great Lakes and inland waters.  One of the questions we are most often asked is, "Underwater, have you ever seen anything extraordinary that really blew your mind?"  The answer is yes!  During the course of our underwater explorations, occasionally we encounter unusual peculiarities of the freshwater world, which the majority of anglers have little knowledge of.  There are even freshwater oddities that I would venture to say, many of you most likely never knew existed.  One in particular, is the existence of freshwater sponges. 

Freshwater Sponge, St. Lawrence River, NY

No.......not the porous cleaning tool.  I'm referring to a living aquatic creature, which inhabits our cleaner lakes and streams.  Thousands of species of sponges thrive in the saltwater environment of the earth's oceans, but believe it or not, there are several freshwater varieties as well.

Once thought to be plants, sponges were not clearly recognized as members of the animal kingdom until the 19^th century.  These lower form aquatic animals have no nervous system, brain, gills, muscles or other organs.  Simply constructed, it's body is made up of a fiberous skeleton and a thin skin containing mostly a watery jelly containing several shapeless cells that perform a variety of tasks.  Sponges gain nourishment through their entire body.  Acting as a sieve, this creature will strain the water catching microscopic life and debris.

Freshwater Sponge, Lake Champlain, NY

Some freshwater sponge species resemble a spreading underwater mold or fungus, which form mat-like encrusting growths.  Those of you, which caught our Lake Champlain episode last season, may have noticed this type growth on the railroad bridge pilings that the bass were comfortably positioned on.

Another lower-form creature we've stumbled upon beneath the surface, and this is a weird one, is the Bryozoa.  In fact last week while shooting an episode on Georgia's Carter's Lake, we encounter several colonies of these aquatic invertebrates.   Commonly known as moss animals, Bryozoa are nothing new, they've been around for more than 500,000,000 years.  The particular species we encountered within Carter's Lake was Pectinatella magnifica and it's larger colonies were the size of a basketball and sort of resembles a beehive hanging in a tree.  The colony is gelatinous, with a firm outer skin and slimy to the touch.  The inner gelatinous mass is 99% water. 

Pectinatella magnifica, bryozoan colony. Carter's Lake, GA

The surface appears divided into rosettes.  Individuals within bryozoan colonies are referred to as zooids, and are not fully-independent animals.  Each type of zooid has a specific function, some are responsible for feeding and excretion, others may act as hatcheries for fertilized eggs.  Each rosette contains 12-18 zooids.  Look for more information on bryozoan colonies in Episode #12 this coming season.