Pond life cycles resemble a ladder. Getting all creatures from the bottom rung to the top requires abundant food. One of the unsung heroes necessary to produce quality fish is plankton. How can a microscopic critter be so important, you ask? How do I grow it? Let’s see!
Plankton are microscopic organisms that feed all aquatic life from the moment they are hatched. You saw photos of phytoplankton and zooplankton in our February newsletter. Properly managed, plankton can triple pond productivity. It benefits not only fish, but every animal in the ecosystem. Use bluegill as an example. Newly spawned fry are hatched with a yolk sack that nourishes them only a few days. When that nourishment is consumed, fry MUST find natural food like plankton or survival rates decline. If plankton is available, survival rates increase significantly. Greater bluegill populations ensure bass, catfish, and other sportfish have ample food to achieve their potential. It’s that simple!
Pond nutrient levels determine plankton density. Some waters receive nutrients naturally from runoff across adjacent cattle pastures. Others may be enriched from fertilized hay meadows in the watershed. Waste from large waterfowl populations is a source. Or, it could be from waste of fed fish. If you don’t have a natural source, ask us about approved commercial fertilizers. The formula MUST have high phosphorus. Generic lawn fertilizers don’t work. We use liquid products with 10-34-0 or granular brands of 12-61-0. Liquid fertilizer is heavier than water and must be diluted at 3 to 5-gallons of water to one-gallon of fertilizer or it will sink to the bottom. Granular products also must be thoroughly diluted or they may sink to the bottom and feed vegetation. Apply most granular mixes at six to eight pounds per surface acre when water temperatures reach a sustained 55 to 60 degrees. Follow instructions carefully. More IS NOT better. It can create serious consequences. Obtain a standard water analysis before applying. Alkalinity levels above 20 ppm are required for good response.
After application, regularly measure plankton development with a secchi disk. The disk should disappear from sight at 18 to 24 inches. If you lose sight at 30- inches or more, do a maintenance treatment with 50-percent of the original quantity. If the disk drops from sight at 15-inches or below, you may experience harmful water quality issues. Contact us for instructions to begin immediate aeration.
Fertilization is also used to manage vegetation. However, it’s all in timing the application. Properly applied before vegetation becomes active, plankton will grow in upper zones of the water column and block sunlight from reaching plants to stimulate growth. Improperly applied, fertilization can accelerate plant growth. Before fertilizing, consult our biologist about current conditions.
Fertilization pays great dividends. But, as you do before making any investment, complete due diligence. Be sure your pond is a candidate for fertilization. Some, especially small ones with high populations of fed fish, may not be eligible. Since plankton grows near the surface, spring-fed ponds with continual spillway discharge should not be treated. Plankton will be flushed-out. Don’t fertilize murky water with visibility less than 12-inches. Suspended clay particles block sunlight needed to stimulate plankton growth.
Spawning season is near. Valuable plankton blooms should be established as early as water temperatures permit. Ask us for a quote to strengthen your food chain and management vegetation.