Welcome to my first of an intended continuous series of articles on ponds and small lakes. I hope this format provides some useful information to pond and small lake owners, be they managing for fishing, swimming, wildlife attraction, or simply for aesthetics. Please, feel free to drop me a line anytime with any of your pond, water, fish, or fisheries questions that aren’t addressed here.
Spring is looming on our temporal horizons, and the time to start planning substantial management actions for your pond is now. Last year, following a relatively mild winter with relatively high average temperatures and precious little chilling snowfall, the phone calls to my office seeking help with managing filamentous algae problems around the state began in early-to-mid-March 2012, technically while winter was still underway! Such a winter tends to kill off less of the past season’s growth and allows pond temperatures to rise into the range to support algal growth much earlier in the season. …More incentive to invest your thoughts into pond management sooner rather than later.
Why now? Problem prevention is almost always easier and more cost-effective than fixing substantial problems after they’ve become established. In addition, once surface-water temperature begins approaching the mid-70s (° F), taking whole-pond management actions that cause substantial kills of nuisance algae and/or vegetation or potentially disrupt pond strata also increases the risk of causing crashes in dissolved oxygen and large fish kills.
If you anticipate problems with filamentous algae or submerged pond vegetation in the coming season, consider applying a dye. The best time for dye application in our region generally begins in mid-March; however, warm winters like 2011–12’s might warrant even earlier application, perhaps as early as late February. Dyes are added to limit the penetration of wavelengths of light that support the photosynthesis required for plants and algae to grow and thrive. These things will begin to grow and draw on sunlight very early in the spring, and you should be striving to limit that growth as soon as it’s beginning, certainly before it manages to reach the water’s surface, at which point dyes are no longer effective. Of course, dyes aren’t particularly effective in ponds with substantial flow-through (like dammed, in-stream impoundments or those with substantial watershed input); big flows tend to flush the dye out. Many manufacturers make dyes approved for aquatic applications. The classic formulae are bright blue, but if you prefer an at-least-somewhat more natural look, black dyes are becoming more common.
If you’re not already, consider aerating your pond. Yes, fountains are considered pretty by some; however, to fully reap the potential benefits of mixing the water column and helping to manage nutrients, you will want a bottom-bubbler/diffuser, something that has the potential to vertically circulate a large volume of bottom water. Again, the time to install such an aeration system is the spring, before your pond has the opportunity to stratify into a separate warm, surface layer (i.e., epilimnion) and a cool (and potentially oxygen-poor) bottom layer (i.e., hypolimnion). (For more information on pond stratification, see the Ohio State Extension fact sheet A-7-01 “Understanding Pond Stratification” on Ohioline). I’m planning a new fact sheet in the coming year addressing the why of it all, but for now, it will suffice to say that a properly designed and installed aeration system can really enhance the processing of pond nutrients, reduce the recycling of phosphorus from sediments (phosphorus that could then promote nuisance algal blooms and excessive vegetation), facilitate the penetration of atmospheric oxygen, reduce the likelihood of fish kills, and enhance the line of productivity that culminates in higher yields of fish biomass.
Canada geese are looking to pair off and set up shop now in anticipation of raising this season’s broods. Perhaps a Canada goose’s greatest ability is eating your landscape—its vegetation and all the nutrients that contributed to its growth—and then gracefully floating around on your pond to “deposit” that “payload” of grazed nutrients directly into your water. Now, I’ll admit that when spending my recreation time on vast, northern, nutrient-poor (i.e., oligotrophic) lakes, seeing and hearing flocks of geese warms my outdoorsman’s heart. Here in Ohio, your recreational pond is not a voluminous, cold, northern lake. The addition of nutrients in the form of goose excrement can substantially contribute to problem blooms of algae or nuisance plant growth on smaller water bodies. It’s a good idea to take every action that is legally permitted to prevent families of geese from establishing themselves on your pond. Harassment, like giving an active dog access to your shoreline, is an effective technique. Another one that’s getting a good amount of recent discussion is targeting geese with laser pointers; they just don’t like that and leave when so “illuminated,” but may return. Whatever technique(s) you choose, the key to effective goose harassment is persistence. (For more information, see Ohio State Extension fact sheet W-3-10 “Coping with Canada Geese: Conflict Management and Damage Prevention Strategies.”)
There is so much more. For questions that remain unanswered and the fact sheets referenced above, please feel free to peruse http://ohioline.osu.edu/lines/ennr.html. … And I’ll write more next time in The Leaf Letter, a new quarterly e-newsletter you can easily subscribe to here.
Eugene C. Braig IV, Program Director, Aquatic Ecosystems Extension, The Ohio State University School of Environment and Natural Resource, 379a Kottman Hall, 2021 Coffey Rd., Columbus, OH 43210, 614-292-3823, firstname.lastname@example.org