 United States farmers have been producing catfish in open ponds for nearly a half a century and do their best to produce a high quality product at a modest price. Global competition, high feed prices and increasing energy costs have required farmers to become more and more efficient in order to remain profitable. Scientists are working with farmers to develop a superior catfish for aquaculture production. They've found that crossing a female channel catfish with a male blue catfish results in a hybrid that is superior to both of its parents and possesses substantial hybrid vigor. The channel blue hybrid grows faster, has better feed conversion, tolerance to low dissolved oxygen, disease resistance and a more uniform shape. The best trait bred into this hybrid catfish is that it's easy to catch. While catching them may be easy, harvesting them from a pond effectively is still a challenge. The hybrid catfish has a small head and a high dorsal compared to the channel catfish. The channel catfish has got a relatively bigger head and a smaller profile this way compared to the head size. And so a channel catfish is kind of more torpedo shaped where it can kind of feed its way through a net a lot easier than a hybrid can. The traditional way to harvest a catfish pond is with a long net called a Sain. The Sain is 6 to 9 feet tall and ranges from 1,000 to 1,400 feet long. It is stored and moved on a large hydraulic reel that is pulled behind a tractor. It has a polypropylene rope with floats on the top edge and the bottom is held down with a weighted line. The mesh size varies depending on the target size fish. The Sain is stretched across the pond and pulled down the sides by two tractors. The bowed Sain funnels fish into a narrow section of net called a throat and into the live car. The farmers have learned through experience how to choose the right mesh size to catch a certain fish. The hybrid catfish however has a slightly different body shape than the channel catfish which can cause problems. This fish is prone to gill in itself and if you use the wrong size mesh the fish will kind of run into the net and it will get lodged in the net right about here. If the pond is harvested when there are too many small fish or the net mesh selected is too big for the population many fish may end up with their head stuck in the net. This is a real headache for both the farmer and the fish. One potential solution to this sticky dilemma was to design a new grading device that can be incorporated into the normal harvesting workflow. Designer David Heikus put a lot of thought into some specific details to improve the Sain's effectiveness and ease of use. Okay I'm standing in the loading area of the live car. This area is going to be closest to the bank where the boom truck can access it with a lift basket. This area right here is about 20 feet long from the zipper to roughly the flexible panel. In this area right here it could hold about 40,000 pounds of catfish. It's got a lip on it to keep the fish from rolling out. Lots of floats to keep it buoyant. And the back half or the back really 80% of the net is covered with a top. And this is just simply to keep the catfish from jumping out as they're stored in the pond perhaps overnight or for several hours. This should give you an idea how long the flexible panel hybrid grading sock is. This particular sock is about 80 feet long. And it should hold about 80 maybe 90,000 pounds of catfish. This is really the working part of the flexible panel hybrid grading sock. What you've got here is heavy duty PVC pipe suspended with steel cables. And on the steel cable you've got black plastic spacers. And these spacers are cut to give, in this particular sock, you can get socks of different mesh spacings. But this particular sock has a 1.975 inch spacing. And that spacing is designed to hold fish that are between 1.5 and 1.6 pounds. So if given enough time a fish less than 1.5 pounds should be able to squeeze to that space. The heavy duty marine zipper replaces the commonly used small metal frame attached to the front end of the live car. This ensures that the sane and live car are aligned and the opening is not twisted. It also greatly increases the area for fish to swim through. Using the industrial zipper the harvest crew attaches the grater to the middle of the sane. Once the tractors reach the end of the pond they start pulling in the sains using large hydraulic reels. Two men at the pond bank work the sane. One man at the base of the levee stands on the bottom of the sane called the lead line to make sure that the fish don't go under the sane as it rises up the bank. The second man shakes out the sane to make sure there are no fish caught in it. As the neck corral gets smaller the fish are forced to the center through the throat and into the live car. Farmhands try to herd the fish towards the live car by splashing the water. Some ponds contain as many as 100,000 pounds of harvestable fish and it makes for quite a sight as they work to find the open section of the sane. A small motorboat with a front mounted push rack catches the top of the sane and pushes it forward to dump mud from the sane. Once the front end of the live car reaches the bank the live car is detached from the sane and the farm workers use long metal poles called dead men to hold up the edges of the live car. This helps create a harvesting basin and keeps fish from swimming or jumping out of the net. An aerator is placed at the bank end of the live car to ensure the crowded fish have enough oxygen. The farmer allows time for the smaller fish to work their way through the greater bars. Depending on the weather this process may take several hours. The tractors and sane reels are moved out of the way so the boom truck and hauling tanker can be moved into place. If it's a large harvest the push boat may split the live car into two smaller areas so one group can be loaded onto the truck while the second is allowed additional time to grade. The fish are lifted out of the live car using a boom and basket and loaded onto a hauling truck to be sent to the processing plant. While many farmers favor the improved growth and feed conversion characteristics of the hybrid there is still much work to be done in determining the best culture and harvesting practices. There is definitely a learning curve associated with the use of the hybrid greater sane and harvesting crews must develop a routine for handling it. We anticipate that as the harvesting crews become more comfortable with the greater that it will become a valuable tool for helping to provide a consistent uniform and high quality product that will make the processors happy and improve profitability at the farm.