The Reason for the Importance
No cost-related task in an aquaculture production operation is more important than feeding. Additionally, feeding is also the most difficult task to perform properly. The cost of feed is about 50 percent of the cost to grow aquatic animals. Some may assume that keeping fish or other aquatic animals alive is more important, but a properly designed system can adequately monitor and control the culture environment so that this task becomes quite manageable.
In any livestock operation, the production process involves converting one form of food into another form. In most cases, this process involves converting plant substances, such as grain or hay, into animal meat such as chickens, hogs or fish. A modest improvement or degradation in feeding efficiency can have a significant impact on profitability of the operation. It is often said that the only person who should be doing the feeding is the person who is responsible for paying the bills. This might be possible for some small operations, but it is not feasible for most. In large operations, the feeding task often is done by the lowest paid workers who are far removed from the financial aspects of the operation.
The Difficulty of the Feeding Task
In feeding livestock, such as chickens or hogs, the number of animals being fed, the feed available to them, and the feeding activity are visible. It is relatively easy to measure the amount of feed each animal eats per unit of time, and it is also easy to insure that feed is always available to the animals. In aquaculture, visibility into the feeding process is limited. The number of fish being fed is not precisely known so an expected amount of feed that the fish should eat is also not precise. As any sports fisherman knows, fish are finicky eaters. Conditions must be just right for them to eat. Feed offered at 3:00 PM might be completely ignored yet the same feed offered at 5:00 PM may be devoured as if they had not eaten in days.
To minimize wasted feed and to ensure that feed is available when fish want to eat, the feeding process must be carefully monitored by the feeder. Feeding on top of the water in ponds using floating feed provides some visible feedback because the feeding can be observed when the fish come to the top to get the feed. If the feed floats on top for 30 seconds to a minute without being eaten, feeding should be discontinued. Careful observation of the feeding process and subsequent fish behaviors are ideally performed by those who are responsible for the economic outcome of the operation.
Feeding with sinking feed is even more difficult because the feeding activity is completely invisible to the person feeding. Various verification methods have been developed over the years. Underwater cameras are used to observe the feeding in deep ocean cages when feeding salmon. Shrimp are fed by placing the feed in trays that are dropped to the bottom of the pond. The trays are pulled up the next day and the amount of uneaten feed is recorded. The trays are replenished based on the expected amounts that will be eaten from each tray. This is a time-consuming and cumbersome method of feeding.
Re-circulating tanks and raceways for indoor culture of fish such as tilapia, perch, flounder, etc. are often equipped with automatic feeders that blow fixed amounts of feed at certain intervals. While this method eliminates the need to physically move large amounts of feed around the recirculation facility, it is also one of the most wasteful feeding processes. Although the automatic recording of the amount of feed distributed is easily done, operators do not receive verification that the feed has been eaten. Some or all of the feed could end up down the drain.
Good Feed Management Practices
An important first step toward better feed management is to establish good feed record keeping and reporting. To give management the visibility they need to make adjustments, feeding should 먹튀검증 be accurately measured and carefully monitored. Many tools are available to help in record and report feeding activity. Wireless input devices are available that will automatically measure and record feed dispersal to ponds, tanks, etc. Reporting software is also available to compute inventory, feed rates, biomass tracking, conversion rates, and to make variance analyses that help identify problem units. Records and reports should provide detailed information to determine the cause of the problem. Even manual recording using a simple spreadsheet is preferable to no records at all.
The largest aquaculture production activity in the U.S. is pond raised catfish. Catfish for the last several decades have been produced in shallow ponds in large part by conventional farmers who also farm row crops. Yields and other measures are reported by acre in much the same way as agricultural crops. Ponds are stocked with small fish at a certain number per acre and are fed at a certain rate of pounds of feed per acre. The rate of feed per acre increases as the fish grow. The expected amount of feed per acre that the fish will eat is a percentage of the fish biomass per acre. The biomass is the pounds of fish in the pond.
The fish in the shallow catfish ponds are fed by blowing feed from a tractor-pulled feeder or specially designed feed trucks. A weight measuring device measures the weight of the feed that has been distributed to a pond. A microprocessor equipped with a radio modem transmits the feeding data to a host computer where it is stored in a database for later analysis. Detailed reports generated from this data provide management with some of the visibility that they miss by not doing the feeding themselves.
Blowing feed into large 12-acre catfish ponds is no longer considered to be the most efficient way of feeding. The trend now is to corral the fish into smaller areas where feeding and aeration are intensified. The results are better feed conversion and better feeding activity due to higher oxygen levels from aeration.
Computer controlled automatic feeding is the ultimate objective toward achieving an efficient feeding process. Greater efficiencies can be achieved by computer automation in the same way they have been achieved in manufacturing operations. Automatic feeding is important, not just for the labor savings aspect, but for its ability to present the fish with more feeding opportunities. When the fish are in the mood to eat, feed should be available to them. This will improve the feed rate per unit of time and decrease the time it takes to grow the fish to harvest weight