By: Allison Holzer Interpretive Naturalist at North Mississippi Regional Park 01/01/2015
When the icy winds of
January blow, many folks like to hunker down, wearing their warmest sweaters
and huddling around hot cups of coffee. Others are happy to get their blood
moving by skiing, snowshoeing or taking brisk walks in many layers of clothing.
Animals are similar: some sleep away the cold days, others trot happily through
the snowy fields. But what about the creatures that live in the water—what
happens to them when the temperatures drop and ice seals over their roofs?
In the early winter,
fish, insects and mussels all continue their lives much as before. In fact,
life may temporarily become easier for some river- and lake-dwelling creatures:
colder water means that more oxygen is available, and when summer plants die,
the small fish and insects have fewer hiding places, giving predators a better
chance at catching a meal.
But as ice and snow build up on the surface, the murky
underwater world becomes much less hospitable. Deep snow and thick ice create a
dark ceiling over the water, cutting plants off from the sunlight they need to
stay alive. Without plants to replenish it, the oxygen in the water is
gradually used up. If this goes on long enough, the fish and other creatures in
the water will suffocate, resulting in what we call “winterkill.” This, by the
way, is why many popular lakes use aerators in the winter—to keep enough oxygen
in the water so the fish don’t die.
Even if there is plenty
of oxygen, though, cold temperatures make life move at a much slower pace in
the winter. Fish, as well as most other lake and river inhabitants, are
cold-blooded; this simply means that their bodies are the same temperature as
their surrounding environment. Some cold-loving fish, like northern pike, trout
and panfish, don’t seem to mind the cold. They are the skiers of the fish
world, and while they do slow down somewhat, they stay almost as active in
winter as in summer. Others, like bass and muskies, get sluggish, eat only what
they need to stay alive, and hunker down. And still others barely eat or move at
all—carp, bullhead and some catfish tend to find a sheltered place at the
bottom, maybe even bury themselves in the mud, and spend the winter in a state
of near-hibernation (not unlike some people I know).
But no matter how they
spend the winter, all fish do their best to use less energy in the winter
months. Predators will take whatever
prey is easiest to catch, even if it’s not what they like best, and will take
longer to digest their meals. River fish will seek out areas with the least
amount of current, so as not to waste precious energy swimming against
fast-moving water, while others will seek out the deeper (and, in the winter,
warmer) areas of lakes and ponds. Just as people huddle close to buildings and
inside bus shelters, fish do their best to stay away from the harshest areas in
their environments.
And so, life is not so
very different for animals beneath the water—some keep moving, others dream
away the cold months, but all look forward to the spring thaw.
Join us at Kroening
Interpretive Center in North Mississippi Regional Park for the following nature
programs. Reservations are required, call 763-559-6700.
New Year’s Day Snowshoe
Hike—Thursday, January 1, 1-3 p.m., ages 8+, $5. Make Your Own
Snowshoes—Saturday, January 10, 10 a.m.-noon., ages 8+, $8/set of snowshoes.
Tree Identification— Tuesday, January 20, 7- 9 p.m., ages 16+, $5. Stories of
the Mississippi—Thursday, January 22, 10 a.m.-noon, ages 16+, $5. Snowshoe
along the River—Saturday, January 24, 10 a.m.-noon, ages 8+, $5.
For young children and
their adults: Feed the Birds—Tuesday, January 6, 10-11:30 a.m., ages 2-5, $5
each – adult and child. Snow and Ice—Thursday, January 8, 10-11am, ages
birth-2, $5 per child, adults free. Making Tracks Puppet Show—Friday, January
16, 10-11 a.m., ages 2-6, $4 each – adult and child
Free Family Fundays:
Come by on Sunday afternoons anytime between 1-3 p.m. for a free family
program, all ages welcome: Feed Me! on
January 4; Snow and Ice Art on January
11; Story Walking: Someone Walks By (co-sponsored by Webber Park Library) on
January 18; and Tales of Scales on January 25. In addition, there will be a
free river walk (The Ice Story) on Saturday, January 3 from 8-9 a.m. Reservations are not required for the above
free programs. Call 763-694-7693 for info or visit Threeriversparks.org.