Nov 21

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Aquaponics Rescues Aquaculture

Salmon Aquaculture Around the World

Salmon is one of the most popular fish in the world and there are currently major efforts around the world to breed salmon through aquaculture. It is estimated that salmon aquaculture is a $12 billion. Norway and Chile produce close to two-thirds of the world’s farmed salmon. Approximately 60 percent (1.26 million metric tons) of the world’s salmon comes from fish farms.


According to World LifeLife WWF, Here are the main impacts of salmon aquaculture:

The rapid expansion of the salmon aquaculture industry has not come without impacts – both real and perceived. The seven key environmental and social impacts are:

  1. Benthic impacts and siting: Chemicals and excess nutrients from food and feces associated with salmon farms can disturb the flora and fauna on the ocean bottom (benthos).
  2. Chemical inputs: Excessive use of chemicals – such as antibiotics, anti-foulants and pesticides – or the use of banned chemicals can have unintended consequences for marine organisms and human health.
  3. Disease/parasites: Viruses and parasites can transfer between farmed and wild fish, as well as among farms.
  4. Escapes: Escaped farmed salmon can compete with wild fish and interbreed with local wild stocks of the same population, altering the overall pool of genetic diversity.
  5. Feed: A growing salmon farming business must control and reduce its dependency upon fishmeal and fishoil – a primary ingredient in salmon feed – so as not to put additional pressure on the world’s fisheries. Fish caught to make fishmeal and oil currently represent one-third of the global fish harvest.
  6. Nutrient loading and carrying capacity: Excess food and fish waste in the water have the potential to increase the levels of nutrients in the water. This can cause the growth of algae, which consumes oxygen that is meant for other plant and animal life.
  7. Social issues: Salmon farming often employs a large number of workers on farms and in processing plants, potentially placing labor practices and worker rights under public scrutiny. Additionally, conflicts can arise among users of the shared coastal environment.

Many salmon aquaculture systems have a different problem; they are trying to find a way to dump the enormous amount of waste generated by the operation itself. Many land-based aquaculture operations have had to cut back or stop operations because their effluent discharges could not be cleaned up enough to meet newer, more stringent water and health standards. The really sad part of this dilemma is that there already exists a very effective method of cleaning up the water so it can be reused and/or discharged back into existing waterways.

This system can even be used for cold water fish and can be used in conjunction with existing greenhouses or farming operations, and can be used to pre-treat the water for reuse in the aquaculture system. The technology has been around for several hundred years in one form or another, is used every day in millions of locations, is safe, easy to operate, and with a tiny amount of modification can produce a highly valuable second crop for the operator.

There are two reasons the technology is not used more. The first is inertia; doing things the same as in the past is very comfortable and familiar. And the other is that the initial cost is high enough to prompt the owner/operators to seek more affordable solutions. This choice is a very short-sighted view because the second income from the modification will quickly pay for the additional expense of the clean up system.

Does this sound too good to be true and you don’t believe it is possible, then you can stop reading. If, however, you are curious as to what this ‘added’ component to aquaculture might be and what it might cost, here’s the answer: Make the system into a modified aqua-PONICS system. Aquaponics is actually a small sewage treatment system that is used to clean up the water that is used to grow fish in by using plants to clean the water so it can be recycled.

Aquaponics to the Rescue

Here are the mechanics of the conversion process: Aquaculture is the growing of single species of fish in a semi-closed or open system of water circulation. It is an excellent example of monoculture. The water flows into the fish holding area for the fish to swim in, get oxygen, be fed in and poop in. The problems come into play when you have the fish crowded, feed them a tiny bit more food than they can eat each feeding so they grow at their maximum rate and then you have to figure out what to do with the waste they are producing in prodigious quantities. Some careful operators use mechanical separators, settling tanks, heavy aeration and even added chemicals to reduce the impact on the fish, if the water is to be recirculated or to try to meet discharge standards if they dump it back into the local water system.

Now we have aquaponics coming to the rescue of aquaculture. Starting at the point where the ‘pick up of the fish waste’ happens in the aquaculture, we are going to add a simple but deeply complex process to how the water is handled.

First we have to get the solids to ‘settle out’ so they can be separated and handled by a branch of the system. Here is where some aquaculture systems have realized that a simple settling system will reduce their waste load significantly. A settling tank or Clarifier is a large container that allows the heavy waste to settle out to the bottom naturally because in is slightly heavier than the water. The water flows in, slows down dramatically and then flows out slower. Physics takes over and by allowing physics to do the work, a huge percentage of the heavy (problem) waste is take out is the primary treatment. Most sewage plants operate this way. Removing the solids first and then the resulting water is much easier to work with because it is less likely to foul the rest of the cleaning system.

Plants Are a Superior Solution to Clean Water

Now come the differences: In most sewage treatment plants after filtering out the lumps, they add a flocculating agent to the water so the remaining water separates out into high nitrogen lumps which again settle out and are moved to a holding area, normally this is the ‘secondary’ smell you sometimes notice at a sewage treatment plant. In aquaponics the ‘clear’ water, the water after the primary treatment is diverted to gravel beds containing, drum roll here, plants. Those wonderful nutrient sucking living things that love nitrogen, phosphorous and other delectables that fish poop provides.

The plants are a living filter system with their roots planted in a flow of nutrient laden water that needs to be stripped of those nutrients in order to be used again. Imagine a whole new income source for the aquaculture owner, ooh, wait, now they are aquaponics owners.

Imagine tomatoes, basil, peppers, lettuces, cucumbers, flower, herbs and other wonderful vegetables growing and helping to treat what was once a waste product. The cost and time to set up the aquaponics is very quickly recovered by the new income sources. Here’s the best part, this same type of aquaponics can be used to clean up almost any waste stream from city sewage, to food processing plant waste, to chicken, hog and cattle raising operations. It’s a slick, elegant, inexpensive and ecologically smart solution.

Viet Nam Fish Farm

WARNING Regarding Asian Aquaculture:

Here is some good advice: NEVER eat fish of any kind that has been imported from Asia, period. If you do eat fish from Asia, make sure it has been certified by the Aquaculture Stewardship Counsel because in most cases, Asian fish is truly not fit for human consumption.

To give you some idea of the unbelievably unsanitary conditions that fish are raised under in Asia, see out this page.

Our warning about NOT EATING ASIAN FISH applies to tilapia, pangasius (catfish), prawns and any other fish imported from Asia.

The Mekong River is one of the most polluted rivers in the world and it is a major supplier of fish raised in captivity. As a matter of fact there are NO RIVERS in Asia that are NOT heavily polluted. And you were going to eat that frozen fish fillet from there? Here is more information: Get real.


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