Delta Journal
by Bob Thomas

There is a new invasive aquatic plant in town! It is Giant Salvinia, Salvinia molesta, a native of South America that is the first cousin of another invasive that has been clogging our waterways for a number of years, Water-spangle, Salvinia minima.

Giant salvinia was first discovered in the U.S. in South Carolina in 1995, and in Toledo Bend, Louisiana in 1998.

A floating fern, giant salvinia grows quickly, doubling its biomass about every week. This rapid growth, coupled with the fact that there are no natural predators in our waters, makes this species dangerous to local ecosystem health. It occludes the surface of the water, thus shading out subsurface vegetation and preventing oxygen exchange between the air and waterways. It can get two to three feed thick, making it impossible for turtles and the like to get a breath of air, otters and alligators to swim and capture prey, and humans to moving about in boats. It quickly clogs drain pipes, and changes the hydrology of wetlands by impeding the flow of water. Heavy infestations can literally kill fisheries and the nursery grounds upon which they rely.

It is surmised that the species’ invasion began by someone dumping aquarium vegetation in the water. This species reproduces entirely vegetatively; its spore capsules do not produce spores in North American populations.

It has spread by simply floating along rivers and bayous, traveling from site to site on the bottoms of boats and trailers, and even on the backs of alligators.

It has been controlled by use of herbicides and the introduction of the Australian salvinia weevil, Cyrtobagous salviniae.

What about this idea? Sautéed salvinia, Rio Grande perch, and apple snails with penne pasta? Yum!