Fall and Winter—Your Pond’s Ally?
By Bob Lusk
With Thanksgiving and Christmas looming, the last thing people tend to think about is their favorite pond. After all, fall has put nature mostly to sleep and we’re near winter…a time for things outside to be at rest.
Your pond doesn’t “rest”…well…okay, I’ll concede that some things do rest. Aquatic plants, for the most part, are dormant. That doesn’t mean they aren’t alive…it means they are squelched. With cold water, most plankton is gone. Fish, being cold-blooded creatures, don’t move much.
At the same time, miraculous things are going on. Water’s affinity for oxygen rises as temperatures drop. That means your water can hold a lot more oxygen during these cold months. Remember this…most oxygen in water comes from contact with the atmosphere and from photosynthesis of living plants under water. Decaying organic matter uses oxygen, although at a much slower pace than during warmer months. Creatures with gills use oxygen, too.
Where are we going with this, you might be asking?
Without ice on top of a pond, oxygen is easily replenished. But, when ice forms, especially in north Texas and the Panhandle, contact with the air stops. So does photosynthesis, unless ice is clear. In older ponds, especially those enriched with heavy sediment and nutrient load from surrounding fields, oxygen consumption can exceed input from natural sources. Then, we have this phenomenon called “winter kill”. Fish suffocate under the ice. That happens sporadically in Texas, but is common north of the Mason-Dixon line.
So, how can you use the frigid effects of winter in your pond’s favor?
Over the last decade and a half, pond aeration has been a trend. With vertical movement of water via different types of machines, mankind can increase water’s ability to process its organic matter load and assist in providing oxygen, too, through greater contact with the atmosphere. Bottom diffusers are quite popular, using high volumes of air pushed to the pond bottom, followed by what looks like a bubble plume similar to Alka-Seltzer to sooth your pond’s upset stomach. There are circulators, fountains and pumps…all designed to move water to assist its cleansing.
You can counteract the possible negative consequences with thoughtful aeration. Heavy on that word “thoughtful”. One of the magical things about ice on a pond is that it actually insulates frigid temperatures above the water line from warmer water beneath that water line. A pond, under ice cover, is actually close to 40 degrees. But, if you happen to be subject to winterkill and choose to run that aeration system, your water will be much, much cooler, pushing almost to freezing. Those who choose to aerate during winter normally aerate only the shallow water, less than four feet deep. One very important caveat is safety. Aeration creates holes in the ice. Those of you in ice country understand the severity and liability of open water. People and animals can go through it. Be careful. Be very careful.
Another way your pond can benefit is that frigid temperatures can wipe out some species of unwanted plants. One common recommendation is winter drawdown. If peripheral plants have become too thick during summer and fall months, drop the pond two or three feet and let nature freeze the roots. If you’re in a region prone to drought, cancel that last recommendation. Asking someone in areas of drought to drop their pond compares to rustling cattle. Water is too precious to choose to lower a pond level to simply get rid of plants we don’t like. It helps to know your plants, then make the call. Drawdown works for some plants and doesn’t for others. For example, coontail, a submerged plant that has no roots and moves with currents, isn’t affected by severe cold. Cattails, left high and dry, can be curtailed…except for the fact they drop seeds on the ground. Those of you east of Interstate 35 have a better chance to refill your precious ponds than those west of that line.
Aeration can be an excellent fall management tool to cleanse water.
What about the fishery in winter? Actually, fisheries biologists often recommend habitat improvement during winter months. Where there’s ice, it’s much, much easier to drag trees and brush out to await spring thaw. What’s the catch here? Be sure to tie on a concrete block and nylon rope to anchor the brush…knowing that the ice might move during thaw and your new brush pile may not quite end up where you want it. If your pond doesn’t freeze over, winter is still a great time to add fish attractors and structure to a pond. Just be safe in a boat.
How about your equipment? Winter time is an excellent time to do all the maintenance you need. Pull the battery from feeders, maintain aeration systems according to the manufacturer, repair the dock, and put those rivets back in your aluminum boat.
While there are some things you can do to use winter as your pond’s friend, there are also things to avoid. Don’t stock fish during winter, unless you work with a professional who knows their way around the business. If you catch a giant bluegill in a neighbor’s pond during frigid weather, don’t automatically expect that fish to survive a trip to your pond for stocking. Avoid handling fish in cold weather. It’s often harmful to the fish.
Just because we’re wrapped in the throes of family, frigid weather and celebrating the holidays, that doesn’t mean we shouldn’t pay attention to our ponds. Winter can be an ally.
Bob Lusk, the “Pond Boss” is in his 36th year as a private fisheries biologist, traveling the nation designing, building, stocking, and managing premier fishing lakes. He’s editor of Pond Boss magazine and has written three books on the topic. “Perfect Pond, Want One?” is his latest and goes into great detail about designing habitat and building the best pond you can. He can be reached at firstname.lastname@example.org or call the Pond Boss office at (800)687-6075.