Many producers have indicated that their markets are requiring HACCP certification. According to Dr. David Green, Extension Specialist in responsible for Seafood Processing and Aquatic Foods, fish producers in North Carolina are not legally required to have HACCP certification. The U.S. Food and Drug Administration's (FDA) Food, Drug, and Cosmetic Act has jurisdiction over the fish farms. This act is enforced in North Carolina by NCDA's Food and Drug Protection Division. Neither FDA nor NCDA issues licenses or certificates for sanitary operations and wholesome food products. As a food supplier, you are expected to have knowledge and comply with the federal and state food safety regulations. The only agency issuing certificates of compliance is U.S. Dept. of Commerce and it is a "for a fee service".
With this situation in mind, Dr. Green and I have been discussing the possibility of having a HACCP workshop for fish producers that would result in producers in attendance receiving a certificate. The workshop would be a condensed version of the two and a half day full version designed for seafood processors. In order to get the federal and state officials needed to attend, we must have at least 12 producers signed up to attend and the workshop would be limited to 25. If you feel that you would be interested and would benefit from such a workshop, please call my office at (252) 482-8431.
During the winter, channel catfish can lose up to 10% of their body weight if they are not fed. By putting them on a reduced or winter feed schedule, you can add as much as 20% body weight to the fish. There is a bit of variation to winter feed schedules, but the following is a good middle of the road schedule:
Water
Temperature % Body Wt. Frequency
oF oC
45-50 7-10 0.5 1X/wk
51-55 10-13 1.0 2X/wk
56-60 13-16 1.0 every other day
61-65 16-18 1.5 every other day
66-70 19-21 2.0 every other day
Some producers will be needing to stock fingerlings as soon as possible, while others may already have enough fish in the ponds. For those producers needing or wishing to stock additional fingerlings into their production ponds, there a few things to remember to help insure the stocking is successful.
First, inspect the fingerlings in the live haul tank to make sure they are not stressed. If you see a lot of dead fingerlings being rolled over in the tank by the aeration system, you may want to reject the fish. Sample the fish with a dip net. The large majority of the fish should not have abrasions or sores on them. You can also check for external parasites such as Ich, which is easily seen on the fish as small white spots that looks a lot like white pepper on the fish. If you see this on the fish, they should certainly be rejected.
Once you determine that the fingerlings are in acceptable shape, you should get a number and weight sample to verify the numbers of fish you are stocking into the pond. This is a very important task so that you get as accurate a count as possible as to the number of fingerlings being stock. The process is fairly simple. Count out a number of fingerlings, at least 100 to 250, and weigh them with a set of accurate scales. Once you have a weight per number of fish, you can calculate how many fish were stocked into the pond by dividing the weight of the sample into the weight of the fish being stocked to get the number. For example, if 200 fish weighed 10 pounds and the truck was delivering 2250 pounds of fingerlings, you could figure that the truck was delivering 45,000 fish. This number is calculated by dividing the 2250 by 10 (since you know that every 10 pounds of fingerlings equals 200 fish). 2250 divided by 10 equals 225 which means that you have 225 batches of 200 fish. Multiplying 225 by 200 gives you 45,000 which is the number of fish you stocked. The only way you can get a bad estimate on the number of fish being stocked into the pond by using this method, is by getting a bad sample. Therefore, you should get a couple of samples of fish from each compartment on the truck to use for your calculations.
Also, fish do not tolerate rapid changes in their water quality, especially rapid changes in temperature and pH. Before stocking fish into a pond, these two parameter should be checked in the pond and the live haul truck and compared. If the water temperature is different by more than 5oF, then the water should be tempered by mixing the pond water and tank water at a rate of change of no more than 0.5oF change per minute. This will give the fish a chance to adjust to the temperature change. If you do not do this, you risk the chance of severely stressing the fish at the very least and possibly killing the fingerlings. A change in pH of more than 1 pH unit can also cause problems. The pH is actually the negative log of the hydrogen ion concentration. This means that there are 10 times more hydrogen ions at a pH of 7 than there are at a pH of 8. This can be a pretty drastic change for fish. It is recommended that the fish be allowed to adjust to a pH change anytime there is a difference of one or more pH units. The tempering rates should be the same as when tempering for water temperatures.
Spring is arriving with warmer temperatures, which means that things will start to happen in the ponds. As water temperatures rise, the nitrosomonas bacteria (the bacteria that breaks down the Total Ammonia Nitrogen (TAN) to nitrite) will become active. However, the nitrobacter bacteria (the bacteria that breaks down the nitrite to the non-toxic nitrate) will not become active until even warmer temperatures. Therefore, be on the watch for nitrite spikes in the ponds. To offset high nitrites, make sure that you have a 10:1 ratio of chlorides (Cl-) to nitrite (NO2).
Spring time is also a fairly stressful time for the fish. They have just endured a prolonged period of cold water and their immunity and natural resistance to diseases tends to be low. It is also in the spring that the naturally occurring antimicrobial substances in the fish's blood are low, making them more susceptible to infections from disease causing organisms naturally occurring in the water. Also, water temperature will increase into that dangerous 18o-28oC range which is optimum for many fish pathogens already present in the pond. It is especially important to keep stress to a minimum during this time of the year to limit disease outbreaks. Water quality parameters that the producer has control over should be kept to as optimum of a level as is possible. Just cross you fingers that water temperatures do not change too much too fast and stress the fish any further. Should your fish show signs of a disease outbreak, get some sick fish (not healthy ones caught on a hook and line or fish that are already dead) to your closest diagnostic facility. Be sure to get an accurate diagnosis. Many bacterial, viral, and parasitic infestations can look similar but treatments are drastically different. If the problem is bacterial and a treatment of medicated feed is necessary, be sure to have sensitivity tests run on the bacterial cultures to make sure the bacteria is sensitive and not resistant to the antibiotic chosen. In many cases, depending on the circumstances, no treatment may be the best treatment and economically the correct treatment. Be sure of what you are dealing with before making your informed decision.
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