How Can I Increase Fish Production?

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How can you increase fish production in your private pond or lake? The answer is surprisingly simple, the methods are simple, but the process is surprisingly complex. It starts with the basic life cycle, which involves how everything in a body of water interacts with everything else.

Fish population and fish size

The number and size of fish populations is similar to the number and size of almost all populations in one way. The availability of food. If enough food is present, the average size per fish, and the population will both rise.

How fish get their food

So, aside from feeding the fish in your pond or lake with a fish feeder, or by hand, how do fish get the food they need to survive and thrive? The answer is in the food chain. Larger fish eat smaller fish, and some insects that cross their path. Smaller fish eat bugs. The bugs eat smaller bugs. The smaller bugs eat algae in the form of phytoplankton.

Phytoplankton production

The answer is pretty simple, for fish to thrive, they need phytoplankton to start the food chain. The obvious next question is: How do I get phytoplankton to grow in my pond or lake?

Well, the phytoplankton already exists in your reservoir. All you need to do, is encourage it to grow by feeding it. The way you feed the phytoplankton is with fertilizer. The fertilizer should be high phospherous, or micronutrients in a delivery system like nano silicates. This will kick start phytoplankton production. I encourage you to do a pH test before you start this type of program, and also to do a secchi test to determine how much phytoplankton is aready there.

See these articles for more detailed information and how to:

Lake And Pond Food Chain

Lake Management Lake Depth Secchi Disk

Pond and Lake maintenance using Diatom Algae

Lake Fertilization

The process works pretty rapidly, and continues as long as the proper fertility exists. This is something that will need to be repeated throughout the summer, but the payoff can be amazing.

Pond and Lake maintenance using Diatom Algae

Pond and Lake maintenance using Diatom Algae

By: Bhaskar M V


 

Water pollution issues in ponds and lakes and solutions to these problems are in the news now a days for all the wrong reasons. Water pollution is increasing due to human activity – increasing population and consumption has resulted in more waste being generated – sewage, fertilizer run off, etc. These enter ponds, lakes, rivers, estuaries, etc., and cause algal blooms leading to low dissolved oxygen problems and fish kills and dead zones. The main source of ‘pollution’ of water is nutrients – Nitrogen and Phosphorus from sewage and fertilizer. Industrial pollutants though more toxic and harmful are a smaller problem in terms of volume. Farmers use fertilizer since plants require them, fertilizers cause higher plant growth and this is a good thing. Why are these fertilizers regarded as ‘pollutants’ when they enter a waterbody? What type of ‘plants’ grow in the water due to these nutrients? Micro algae i.e., Cyanobacteria, Green Algae, Dinoflagellates, Diatoms; macro algae, aquatic weeds, are the various plants that can grow in water. The problem arises when the balance shifts in favor of one group and this dominates the water. Thus when there is a large bloom of Cyanobacteria or Dinoflagellates the water turns Green or Red and some of these species release toxins too. Water hyacinth or Duck weed too can bloom and cover the pond or lake. Which is the best species / group of ‘plants’ to grow in water? How to maintain the desired ecological balance of various species? We believe that Diatom Algae are the best group of micro algae to grow, they are the best food for fish and hence do not accumulate in the water. Cyanobacteria / Blue Green Algae, Dinoflagellates, water hyacinth, etc. are not consumed by zooplankton, fish, etc. and hence accumulate in water and become a nuisance and have to be removed by artificial means – physically removed or by use of algaecides and weedicides. Diatoms on the other hand are removed naturally by Zooplankton and fish. Catching fish is easier and more profitable than harvesting algae. Diatoms typically dominate water during spring, early summer and winter. Late summer is when Cyanobacteria and Dinoflagellates bloom and dominate the water. The reason for this is that Diatoms require more inputs than other micro algae, they are the most recent of the micro algae to have evolved – less than 300 million years ago. Cyanobacteria evolved more than 3000 million years and Dinoflagellates about 1000 million years ago. Thus Diatoms are the more complex of all micro algae and they require many micro nutrients and Silica to bloom. Iron, Manganese, Zinc, etc., are the micro nutrients require by Diatoms. These and Silica do not dissolve easily in water. Metals oxidize in water and silica (sand) is not by nature soluble. Thus these elements are the first to be exhausted in water leading to the end of Diatom bloom in early summer and consequent domination by Cyanobacteria. Thus is supply of silica and micro nutrients is increased the Diatom bloom can be prolonged and the bloom of other algae and weeds controlled. N P K are the inputs that are common to all plants and algae, thus when these are consumed by Diatoms other plants are starved out. However, since Diatoms are grazed upon by Zooplankton and fish their population is regulated naturally and the bloom will not get out of hand if adequate number of fish are available and if the silica micro nutrient supply is regulated. Thus the natural ecological balance can be restored and maintained throughout the year. A solution to provide silica and micro nutrients in water in a stable manner has been invented by Mr T Sampath Kumar of Bangalore, India. He researched for over 10 years from 1994 to 2004 and perfected the formula. Its now patented and marketed under the name Nualgi [NUtrition for Algae] . Nano silica is used as a base for delivery of all the micro nutrients. Nano silica disperses in water and does not dissolve, however the dispersed nano particles behave in the same manner as dissolved particles. The silica keeps the metals stable in water and prevents them from oxidizing. Thus metals in Nualgi are stable in water for a long time and they are bioavailable to the Diatoms. The maximum dosage of Nualgi is 0.25 ppm i.e., about 1 kg in 1 acre of pond 1 meter deep. The Diatom bloom lasts for about a week, so repeat doses have to be given weekly. The cost of Nualgi used is fully recovered from sale of fish. 1 kg of Nualgi results in 100 to 200 kgs of Diatom biomass. This results in 10 to 50 kgs of fish biomass. 100 kgs of Diatoms give about 100 kgs of oxygen and absorb 137.5 kgs of CO2. Diatoms bloom rapidly and the color of water changes from green to light brown in a few days. When Nualgi is used in a pond with a massive Blue Green Algae bloom the BGA may crash within hours of the first dose. Nualgi is thus a safe and economical alternative to mechanical aerators, algaecides, dyes, etc. Bhaskar www.kadambari.net

Lake Fertilization

Pond management and lake fertilization



There are times in the life of a pond or lake when clearing the water may be necessary. At those times, there are flocking agents that will do the job well. You should be aware however, that a completely clear pond or lake is not the optimum circumstance for a healthy body of water. Unfortunately, there are many who suffer from the illusion of healthy happy fish in a beautiful crystal clear pond, but it is just that, an illusion! For healthy fish, and for a healthy pond ecosystem, there must be something growing in the water, and that something is phytoplankton. The way to get it is through fertilization.

Nowhere in the world of living things can the effects of fertilization be seen more clearly than in a pond or lake. The effect can be almost immediate, and often drastic. The results, if properly implemented, will be a near incredible increase in fish size and numbers. Properly timed and implemented fertilizer applications will also reduce the population of unwanted submersed and emergent weeds.

An analogy: Cattle pastures and fish ponds

Think of it in terms of a cattle pasture. If you fertilize the grass, the cattle will grow more quickly, and the pasture may be able to support more cows. Reproduction will increase, and pounds of milk or beef per acre will increase. Lake fertilization works the same way. Increased pond fertility will increase the food source for your fish, which will increase their size and numbers. If done properly, you will also cause the grasses to outgrow the weeds.

What kind of fertilizer and how much

Fertilization will produce algae bloom, or phytoplankton in your pond. The right fertilizer is a fertilizer high in phosphorous and low in the other 2 elements. Phosphorous is the middle number in the 3 numbers listed on a bag of fertilizer. You need to add 40 lbs of 20% phosphorous, or 20 lbs of 40% phosphorous, or something similar in ratio per acre to initiate algae bloom. It takes about 4 to 8 pounds of pure phosphorous to produce or maintain algae bloom in an acre of water. If you had a product with 80% active ingredient, you would need about 10 pounds. However you get there, you need about 8 pounds of the second number in the fertilizer label, and as little of the other ingredients as possible.

There are some great pond and lake fertilizers available, but if you can’t find them, regular old high phosphorous agricultural fertilizer granules can be used. There are also liquids available, but when using liquids in a pond or lake, always remember that the fertilizer is heavier than the pond water, and will sink to the bottom unless you add water before releasing it into the pond water.

An alternative to phosphorous for pond fertilization

With phosphorous being closely monitored today, and restrictions on the horizon, it may be a good idea to look into alternatives such as the ones mentioned in this post by Mr. Bhaskar on our Lake Advice Blog: Diatom Algae. For the details on various methods fertilize your pond see Pond Fertilization Methods . Find more information about the effects of lake fertilization throughout this site.

How To Fertilize A Pond Or Lake

 

So, you have had a few problems with your pond or lake that seem to indicate that you need a little extra fertility. Maybe what tipped you off was:

  • Poor fishing
  • Skinny fish
  • Low fish population
  • Excessive pond algae like blanket weed or pond scum
  • Excessive lake weed growth

Whatever it was that tipped you off, you have come to the conclusion that something has to be done to increase fish production, get rid of lake weeds and pond scum, and prevent these problems in the future.

  • You have done your homework.
  • You have tested the water clarity of your lake and solved any problems related to soil particles in the water.
  • You have checked the pH and corrected it if needed.
  • You have water which is too clear to support aquatic life, so you know that you need to produce algae bloom, and you know that that means you need to fertilize your lake.

How do you fertilize a pond or lake?

There are several suitable methods for pond and lake fertilization, but let me start off with a few cautionary statements.

Liquid pond fertilizer

Liquid fertilizer should be mixed with water before being applied to a lake or pond. The liquid fertilizer will be heavier than the water it is being applied to, and will sink to the bottom where it will probably either be neutralized, or initiate unwanted plant growth.

Keep fertilizer clear of outflow

If you are using buckets or platforms suspended in the water to slowly dissolve fertilizer, make sure that they are not close to your spillway or drain pipe. This could result in the majority of your fertilizer ending up downstream.

Simple pond fertilizer method

If you are using fertilizer in plastic bags, you can lay the bag in shallow water, 2 to 3 feet deep, and slit the top lengthwise and across to allow the fertilizer to dissolve.

Fertilizer platform

If you are using a submerged platform, the platform should be about 1 to 2 feet below the surface of the water, and the proper amount of granular fertilizer can be dumped onto the platform and allowed to dissolve at it’s own rate.

Fertilizer in a bucket

The same result can be attained by suspending a 5 gallon bucket full of fertilizer with small holes drilled into the sides from a dock. be sure that it is one to 2 feet deep.

Fertilizer products formulated for ponds and lakes

There are a lot of newer fertilizer products on the market specifically designed for pond and lake fertilization that offer other options such as finely ground granules. These products come with instructions and label directions.

Special aquatic weed control note:

It is important to start fertilization early in the spring. If algae bloom is in place before weeds and filamentous pond algae have a chance to get started, this will decrease the amount of weed control needed for the pond. See also: Lake Fertilization