Written by Industry Experts, Aaron Cushing and David Beasley, Fisheries Biologists
Plankton are the base of the food chain in ponds and lakes and are broken down into two categories: phytoplankton which are microscopic plants (green) and zooplankton which are microscopic animals (brown). Having a healthy and prosperous plankton community lays the foundation upon which an entire healthy and prosperous pond ecosystem is built.
Phytoplankton relies on three primary things to grow: sunlight, available nutrients, and water temperature above the mid 50’s. The primary predator to phytoplankton is zooplankton. Large phytoplankton populations will give the water a green color, whereas large zooplankton populations will give the water a brown color. Phytoplankton and zooplankton populations will naturally fluctuate back and forth, resulting in the water color changing between bright green, olive green, olive brown, brown and clear. In ponds with aeration, the plankton populations tend to be more stable due to more consistent water chemistry. In waterbodies where an abundant population of pond fish is desired, plankton populations can be increased using fertilizer.
Next up the food chain are larger invertebrates. Invertebrates such as aquatic insects feed on plankton, plants, small fish and detritus (decaying organics). Invertebrates play an important role as food for even larger invertebrates and fish, while they also further the decomposition of organics. A healthy, high quality invertebrate population hinges greatly on good healthy water. With a good population of invertebrates, small fish will prosper.
Small fish are very important to the food chain, as large fish depend on them for food and survival. Small fish feed heavily on both phytoplankton and zooplankton, while also consuming available invertebrates and other small fish when possible. It is important that small fish have abundant food available to give them the needed energy to face life’s challenges. Survival for small fish is difficult, so having abundant plankton is ideal.
Finally larger fish begin playing a role, primarily feeding on invertebrates and smaller fish. Fish diets vary between the species, but most fish tend to feed on what is readily available. These predator fish are much more vulnerable to going hungry than those lower in the food chain since they are relying both on the smaller fish’s success, while also competing with their own tendencies to over populate. Too many top-end predators will put a large strain on the smaller fish, bringing instability to the food chain. It is very important to actively remove top end predators such as bass and crappie from ponds before they overpopulate.
The food chain is relatively straight forward and ties directly into the much larger picture of the “Food Web”. The Food Web includes the “Food Chain” along with all the Aquatic and Environmental variables that influence the aquatic life such as vegetation, water quality, runoff, sunlight, etc. To maintain a prosperous aquatic environment the food chain needs to be in check, and the Food Web needs to be understood. Many ponds often require the assistance of aeration, vegetation treatment, grass carp, additional forage fish, harvesting predators, along with many other fishery management practices. There are dozens of variables that can be modified to bring stability to the ecosystem.
Contact the experts at 888-480-LAKE (5253) for all of your lake, pond and fisheries management needs.
Aaron Cushing and David Beasley are Fisheries Biologists with SOLitude Lake Management. Since 1998, SOLitude Lake Management has been committed to providing full service lake and pond management services that improve water quality, preserve natural resources, and reduce our environmental footprint. Lake, pond and fisheries management services, consulting, and aquatic products are available nationwide. Learn more about SOLitude Lake Management and purchase products at www.solitudelakemanagement.com.