A common problem in Maryland waters is the diatom, Didymosphenia geminata. A serious pest in Australia, Argentina, Chile, and New Zealand, and is causing massive damage to Maryland streams and rivers.
The stalks of this diatom attaches to rocks, plants, or other submerged surfaces. At the time the diatom cell divides, through vegetative reproduction, the stalk divides too, eventually forming a mass of branching stalks. The nuisance build-up is not the cell itself, but their massive production of extracellular stalks. Extracellular polymeric substances (EPS) that form the stalks are made primarily of polysaccharides and protein, forming complex, multi-layered structures that are resistant to degradation.
First seen in the Gunpowder River in Maryland, it has now spread to the Save River and branching areas. By the massive build up of stalks, didymo smothers trout spawning beds, plant life, insects that are a food source, clogging up waterways, choking out sunlight and nutrients, and being very unsightly. The problem has even caused the authorities of New Zealand, one of the best trout waters in the world, to ban felt soled waders, which may spread the diatom. Now, didymo is coming closer to America’s most pristine trout streams.
What can be done?
To prevent the spread of this serious pest, make sure to wash all waders, boats, and anything that touched the water with a salt – water mix. Make sure to tell other fisherman and swimmers about this threat. If it is not stopped, the government, which is already considering some things, may ban some of our equipment or make access much harder. Plus, you need to your gear after trips anyways. Just all some salt or bleach to the mix. Fish responsibly!