A farm pond is a food chain

By MINDY POEHL | Central Texas Edition

Fisheries specialist, Michael Masser, reminds pond builders of the ecological and natural development necessary to building good farm ponds. -- Photo by Mindy Poehl

June 3, 2004 -- If you are going to construct a pond on your property, you should get help through the Natural Resources Conservation Services (NRCS). This was the opening ad-vice given to property owners (farmers) attending this year's special pond management meeting held May 25 at the McClennan Community College's Highlander Ranch.

Dr. Michael Masser, Extension fisheries specialist with Texas A&M University spoke about managing ponds on farms. "It takes special understanding and knowledge to build ponds," he said.

Masser began speaking about pond construction. "When constructing a pond, keep woody vegetation off of the dam area because the roots will poke holes in the dam once the vegetation begins to grow," he said. "Also keep cattle away from the banks because they will erode the banks and increase the nutrients in the pond. Feed the cattle water in a trough or fence off a certain area around the pond and fill the banks with gravel. The gravel will hurt the animal's hooves and they will leave the area once they drink the water," Masser explained.

According to Masser, the clay content in a pond should be greater than 30 percent. The soil pH in a pond should be greater than 6.5. The water pH should be between 6.5 and 9.5. To measure the turbidity of the clay he said to look at the watershed around the pond. To clear muddy ponds, he said use gypsum, which clears 70 percent of the water or use alum, which clears 90 percent of the water.

Masser centralized the entire speech around the food chain.

"Aquatic food chains are important because we're dealing with animals, and animals have to eat, or they won't grow," Masser said.

He explained that fish do not chew their food as humans do. They swallow their food whole, so their mouth size corresponds to food size. Fish are also cold blooded and do not use energy for maintaining their body temperature, as humans do. They do not need much energy or much food.

"That's why they are more efficient in food conversion," Masser said.

Food chains are the step by step processes in which energy is transferred. The energy loss for digestion and excretion is approximately 90 percent. For a fish to grow one pound, it must consume 10 pounds of prey.

The food chain in a pond flows as follows: Plants turn in to detritus, which is decaying matter, herbivores eat the plants and detritus, then carnivores eat the herbivores. To keep fish in a pond, plants must be grown.

"As human beings, we want to see clear water," Masser said. "But in reality, clear water doesn't contain much life. Food chains begin with plants, so if you like clear water, you get cleared, empty land. To keep plentiful land, green up your pond."

Masser said good fertilization can add plants to ponds, which also increases the fish production. Fertilizers are high in phosphorous. Phosphorous precipitates to the bottom of the pond and gets trapped in the mud. That is why rooted plants do well in ponds.

To measure the greenery in ponds, you can use a Secchi Disk. It is a disk sunken into the water on a rope. If the disk disappears at 18-24 inches, the pond has a good bloom. If the disk disappears at a depth greater than 24 inches, then the pond should be fertilized. If the disk disappears at 12-15 inches, the greenery is too dense. If the disk disappears less than 12 inches, then there is a depletion of oxygen in the pond.

Fertilizers increase the fish production four to six times. Masser suggested not fertilizing rooted vegetation and warned not to over fertilize the pond.