"One Fish Two Fish Red Fish Blue Fish"
Most of us recognize “One fish two fish red fish blue fish” as the title of a popular children’s book by Dr. Seuss, but what does Dr. Seuss have to do with conservation?
It really isn’t that much of a stretch to link the two. Animals play prominent roles in many of Dr. Seuss’s stories, and in his book The Lorax a group of animals is pushed to near extinction as their habitat is destroyed.
This article is about lake sturgeon, a fish that was almost completely eliminated from Missouri waters because of habitat loss, pollution and overharvest. By 1910, catches of lake sturgeon were rare in Missouri.
Lake sturgeon are ancient-looking fish that feed primarily on insects, although they will sometimes eat fish and crayfish. Their mouth is a short, toothless, retractable tube that they use to suck food from the river or lake bottom. Their body is protected by numerous bony plates, each having one or more small—but sharp—raised spines.
The species is Missouri’s largest and longest-living fish. Lake sturgeon more than 100 years old and weighing more than 200 pounds are occasionally caught in several northern states and Canadian waters.
Lake sturgeon were listed as endangered in Missouri in 1974, thus protecting them from all harvest. The Department of Conservation then worked out a long-term plan that included a stocking program to help this species rebound. The first fingerlings were stocked in the mid-1980s. Lake sturgeon don’t begin reproducing until they are nearly 20 years old. After that, they only spawn every three to seven years.
As part of the long-term recovery effort, fisheries biologists have been catching and tagging fish with transmitters to track their movements and to help learn more about what habitats they prefer, what their home range is and where they will go to spawn.
Touching on Transmitters
Radio and ultrasonic transmitters are commonly used in fisheries work. Radio transmitters work like miniature radio stations. Each emits a different and identifiable signal. The transmitters we use are small and are powered by a C-cell battery encased in epoxy. In most cases, we have to be within a half-mile of the fish to pick up their signal.
To hear the signals, biologists use a special receiver that works just like a radio. If we want to listen for a specific fish, we simply turn the dial to its transmitter’s unique frequency.
Our receivers also include a feature that allows us to scan for all signals.