Drained by our
country's two largest rivers and cut by many smaller streams and wetlands,
Missouri has always been prime otter country. However, the bulk of the
population was eliminated in the 1800s as the fur men moved west toward the
beaver waters of the Rockies. Throughout the 20th century otters have been
uncommon in Missouri; in 1970 it was estimated that fewer than 100 animals
remained. Most of these were in the Bootheel, an oddly shaped appendage that
hangs off the southeast corner of the state and includes some wildish
Mississippi River bottomlands.
The purpose of the
otter experiment was to reestablish the animals outside the Bootheel,
particularly along and north of the Missouri River, where, except for
occasional transients, there probably had been no otters for at least 50 years.
To this end, state biologists conducted detailed habitat surveys. It was
decided that the best locale for releasing the first otters was in the Grand
River watershed, some 20 miles upstream from the confluence of the Grand with
the main stem of the Missouri. The Grand flows from the Iowa border in a
southeasterly direction and its wet, low-lying valley is laced with many small,
slow-moving streams. They wind through vast soybean and cornfields, but because
the land is too wet and muddy to be farmed economically, they are choked with
junglelike vegetation. This provides excellent cover for otters. Equally
important, the waters produce an extraordinary tonnage of crayfish, suckers,
catfish and other protein sources upon which otters thrive.
"I have always
been amazed at the fertility of the Midwest," says Erickson, a 31-year-old
native of the gnarled mountains of central Pennsylvania. "It's as good a
place for wild species as it is for soybeans, corn and cattle, and for the same
reasons—rich soil, moderate climate and abundant water."
Another reason for
selecting the lower Grand Valley for reintroducing otters was that some 10,000
acres of it comprise the Swan Lake National Wildlife Refuge, well over half of
which is covered by shallow impoundments and marshland. Swan Lake is best known
as the winter home for a flock of some 150,000 Canada geese. (The nearby
village of Sumner claims to be the Wild Goose Capital of the World.) However,
it provides good habitat for a great variety of other resident and migratory
species, and may be one of the most productive wildlife tracts on the
Also, because it
is a federal sanctuary and closed to trapping, Swan Lake gives otters as much
freedom from human predation as is possible. In Missouri the species is
protected absolutely, and, the threat of stiff fines aside, no one involved in
the otter restoration is overly worried about fur trappers as putative
poachers. To the contrary, the Missouri Trappers Association, for reasons of
sentiment rather than commerce, contributed $1,500 to be used for the otter
restoration experiment, the total cost of which will be about $10,000 for 1982.
However, there are a number of perfectly legal beaver trappers in Missouri, and
there is no way of guaranteeing that otters, which are not particularly
trap-wary, don't end up in their sets. By releasing the first animals on the
federal holding, it was thought that they would at least commence their
Missouri residency in a place where there are no risks of such accidents.
Swan Lake as the best place to begin the experiment, and with the cooperation
of the Federal Government, Missouri agents began dickering for otters. Because
of the state's success in restoring wild turkey populations, there is now an
abundance of the birds, and of a strain particularly suitable for other areas
in the South and Midwest. Therefore, 32 of breeding age were live-trapped and
sent to Kentucky, which had very few turkeys and wanted more. In return, for
$8,000 Kentucky bought 20 adult otters, 10 of each sex, from private trappers
in Louisiana and sent them to Missouri.
Nobody is sure how
many otters there are in Louisiana. For this species, as for most others,
wildlife census figures are fairly meaningless, being derived from small
samples and a great deal of extrapolation. However, each year Louisiana
trappers take about 10,000 otter pelts. The removal of the 20 animals for
Missouri had next to no effect on the status of otters in Louisiana. When they
arrived from Louisiana many of the 20 bore trap and mating scars. Otters, like
many of the mustelids—the weasel family—conduct rough to bloody courtships.
These marks pleased rather than distressed the Missouri biologists for they
indicated they were receiving truly wild animals. "Otters aren't easy to
come by, and you have to take what you can get," says Erickson. "We
were hoping we wouldn't have animals whose behavior had been altered by being
raised or held too long in captivity. There was no question about the wildness
of the ones we got. I've never dealt with animals so determined and able to
defend themselves as these otters. We were extremely careful with them—for
their welfare of course, but also our own." That made sense; otters are
powerfully muscled creatures with formidable teeth. There are stories of
imprudent trappers having arms and hands mutilated by unsubdued captives.
Two batches of
otters were sent to Missouri; 13 animals in March, the remaining seven in May.
All were shipped directly to Swan Lake, where a facility had been prepared for
them. They were met by three veterinary surgeons from the University of
Missouri. After giving the animals a general health examination, the vets made
an incision in the side of each otter and inserted a radio transmitter, which
will float freely in the body cavity for the rest of the animal's life. The
transmitter is about the diameter (⅞ of an inch) of a standard C flashlight
battery and almost twice as long (three or four inches) with a six-inch strand
of antenna wire extending from some models. These devices are expected to emit
signals for up to 500 days—the maximum time current lithium technology
permits—allowing Erickson and his associates, using mobile receivers, to keep
more or less constant tabs on the free-roaming otters during that time. In
addition to routine beeps, the transmitters are designed to emit a
"mortality signal." It begins if vital activities cease for several
While not exactly
defensive about the use of these devices, the Missouri researchers are well
aware that they are controversial (see box, page 82). It is difficult not to
think about what it might feel like to have a double C cell rolling around
one's own innards. In response to humanitarian objections, Erickson says that
the technique has been used successfully with other feral mammals, who after a
short recovery period have shown no signs of discomfort or even that they are
aware that they are carrying radios inside them. A more conventional method for
equipping wild animals with radios is to attach a transmitter to a neck collar,
but with beasts of the weasel build this is next to impossible.
that in the case of the Missouri otters, radiotelemetry is justified; that
without it the chances of successfully reintroducing otters would be sharply
reduced. "Obviously, we hoped that all of the first 20 animals would do
well, reproduce and become part of a new population here," he says.
"But this is also an experiment aimed at learning how to reintroduce
otters, something that up until now nobody has learned much about. We think an
area like Swan Lake is an excellent one, but we have to test that assumption.
If we have problems that we didn't foresee, we will try to correct them when we
release the next 40 animals in the spring. To do that we have to have a fairly
good idea of what has happened to the first otters—how they have responded. And
keeping track of something like an otter in this kind of habitat is virtually
impossible without using telemetry."