As an algae with a gross nickname invades pristine trout streams across the U.S., Maryland is about to become the first state to enforce a ban on a type of footgear the organism uses to hitchhike from stream to stream: felt-soled fishing boots.
The state Department of Natural Resources plans to prohibit wading with felt soles starting March 21 to curb the spread of invasive organisms that can get trapped in the damp fibers and carried from one body of water to another.
Similar bans will take effect April 1 in Vermont and next year in Alaska, aimed especially at didymo, a type of algae that coats riverbeds with thick mats of yellow-brown vegetation commonly called "rock snot."
Maryland fishery regulators say didymo, short for Didymosphenia geminata, can smother aquatic insect larvae such as mayflies, stoneflies and caddis flies that are favored food for trout.
*Not a lot of economics content here--beyond the obvious externality created by invasive species--I just wanted an excuse to post the name 'Rock snot.'