Too Much of a Good Thing
My grandma is a great cook, which might be why I grew up with a healthy appetite. Her freshly baked cinnamon rolls were one of my favorites, and one Saturday morning I polished off a whole pan of warm rolls covered with melting peanut butter. Needless to say, I overdid it a bit and was pretty green the rest of the day. This was my first memorable lesson of "too much of a good thing."
For those of you who have fished Pool 1 in the summer, it too can look a little green. This green appearance can also make your stomach ache, but for a totally different reason. All of the vegetation in and on top of the water can make it pretty darn difficult to fish.
Changing Plant Communities in Pool 1
Sixty years ago Pool 1 was forested and looked similar to pools 2 and 3. The plan for the area was to catch water from the Castor River in the fall and flood the impoundments for waterfowl hunting. Unfortunately this plan didn’t work, so early on the decision was made to make Pool 1 into a storage reservoir. This pool is 1 mile wide and 3 miles long. The land falls only 6 feet from north to south, making it a rather shallow lake.
It wasn’t long after Pool 1 was permanently flooded that its potential for fish was realized. Plants responded to the permanent, clear, calm, shallow water. As the timber died back, the aquatic plants surged forward. The change in vegetation from trees to aquatic plants is easy to see. What has been a little more difficult to observe is the constant power struggle and change that has occurred with the plants living in and on the water.
Aquatic Plants Benefit Fish
The floating and submerged vegetation is the blessing and the curse of Pool 1. The big floating leaves provide shade. The submerged stems and leaves provide structure and food for a variety of critters (microbes, bugs and fish of all sizes). Additionally, the plants act as small aerators by taking in carbon dioxide and pumping out oxygen into the water column. Despite Pool 1's shallow depth, the vegetation is what drives the healthy fish population.
Some lakes may be considered great crappie or largemouth bass lakes. However, Pool 1 has a host of species that are a great size to catch, including bluegill, black crappie, largemouth bass, redear, chain pickerel and warmouth. The challenge of fishing Pool 1, however, is its aquatic vegetation requires a little more patience and light line. You'll get hung up on the vegetation, but that is where the lunkers are.
Although vegetation harbors the fish, it also makes them hard to reach. Therefore, we’re controlling Pool 1’s aquatic plants. Unfortunately, there isn’t a one-brand-fits-all herbicide out there… at least not one that is approved for aquatic use and that wouldn’t kill all of your fish too.
The Aquatic Plants of Pool 1
In Pool 1 there are many species of plants that tie up space in the water column, but they typically fall into two groups.
Submergent vegetation are plants that grow and stay under water. Coontail, Eurasian watermilfoil, bladderwort, fanwort and Elodea (also called American waterweed) are the main submergent species found in Pool 1. As I mentioned earlier, the distribution and density of these species has changed over the years. Coontail and watermilfoil used to be the dominant submerged plants in Pool 1, but in 2001 fanwort started become more dominant and outcompeted the coontail. Since 2009 Elodea has come into the picture and is becoming a larger player.
On the water’s surface there is more than just one type of lily or floating, leaved plant. American lotus, water lily, spatterdock and water shield are the four main species. You can tell the difference between them by their leaf size and shape and their different flowers. American lotus is the largest. It has a round leaf that can also extend above the water’s surface.
In the past, this plant had stayed on the north end of the pool, but recently it has increased across the southwest corner. In 2003 a few small patches of lotus covered less than 7 acres in this portion. Since then, the area covered by lotus has continued to expand on average 15 acres per year. In 2010, roughly 122 acres were covered by lotus in this section of Pool 1.
So what is our strategy to keep this dense mat of vegetation back so it is easier to fish?
As I mentioned earlier, there isn’t a simple solution. Pool 1 is 1,800 acres, and treating the whole area is not feasible. Additionally, since these plants compete for the same light and space in the water column, once you remove one species another will move in and take up the empty space. The plants on top of the water require a different herbicide than what is necessary to treat the plants below. The application of herbicides has its challenges, too. We have typically applied herbicide by boat, but the area that can be covered is limited. Aerial application is an option, but the location and potential negative effects to the cypress must be considered. However, this probably will be our next step.
Given these trade-offs in attempt to get the biggest bang for our buck, we have focused most of our control efforts in the southern half of Pool 1 near the boat ramps, fishing piers and bank line. We use EPA-approved herbicides, which means there are no concerns about fish consumption, to target our main problem plants.
Submergent Vegetation Control
The bottom line is that submerged plants are hard to control. Since fanwort is currently the most dominant species, we have focused on treating this species every other year. We use fluridone, which is slowly absorbed by the plant over a 45-day period. To maintain effective concentration of the chemical, we apply this twice during the summer in the southwest corner of Pool 1. By applying it here the levees and trees minimize the amount of wind fetch and mixing of the water. This prevents dilution of the herbicide and gets a better kill. This treatment generally knocks the fanwort back across 150 acres the first year, and during second year it starts to creep back into the treated area. We get two years of control on the fanwort because of this lag effect. A new herbicide was just approved by the EPA this year. We’ve got our hands on some and will be experimenting with it next year.
Floating, Leaved Plant Control
In the past we have tried annually to keep the floating leaved plants off of the bank lines and created boat lanes by spraying herbicide on our floating leaved plants. The aquatic version of Roundup, which uses glyphosate, is used for this effort. This herbicide kills the plant tissue it comes in contact with, so you typically see quicker results than what we see with the fluridone.
The expansion of lotus throughout the pool is a growing concern. Over the last month we have been spraying herbicide by boat to knock back a wider portion of the lotus that has popped up on the southern end of the lake. By working on the lotus in the same area where we’ve knocked back the underlying fanwort, we should start to see a broader area of open water for easy fishing. We also may do an aerial application to get a better handle on the lotus across a wider area.
No Silver Bullet Approaches to Natural Resource Management
One of the challenges in managing a conservation area is that the plant and animal communities never sit still. There is always a group of species on the rise while others are on the fall. Management is the art of trying to tweak the system in a way to get a reliable response to benefit public use of these variable resources. For every one of our actions there is a response. Some of these can be anticipated while others cannot. No doubt nature will always have a new challenge for us tomorrow.
Pool 1 and the plants that call it home are definitely a challenge to manage and fish through. However, this very habitat is why folks have filled their coolers with fish over the last 60 years. Hopefully, this post has been helpful in describing how we’ve gotten “too much of a good thing” in Pool 1 and what we are doing to manage it so the public can have access to the awesome resource below.
If you have any other questions please contact us at the Duck Creek Office or our fisheries biologist, Paul Cieslewicz, at the Regional Office (573-290-5858 x240, firstname.lastname@example.org). Thanks again for your interest and dedication to the area. Good luck fishing.