 Aquaculture, the farming of fish in freshwater, dates back to old world times in Asia, when native fishes were cultivated to augment food supplies. In this sense, aquaculture and agriculture have much in common, since both supply of food for a growing world population and both utilize impact and conserve natural resources. Hello and welcome to Aquaculture Today, an informational program about aquacultural issues sponsored by the Southern Regional Aquaculture Center. Today we're going to examine a hot issue in aquaculture, avian depredation on fish farms. Like any agricultural commodity, aquaculture faces many challenges as it increases in scope and value. One of the most pressing and frustrating problems facing many fish culturists in the southeast is predation by fish eating birds. Since the early 1980s, this has become an increasingly significant problem for southeastern fish farmers, especially the catfish industry centered in Mississippi. Although detailed economic impact figures are still being developed, it is clear that the economic costs associated with heavy feeding by large numbers of predacious birds can be locally severe. A 1988 survey of catfish producers in Mississippi revealed that fish farmers spent over $2.1 million annually to ward off fish eating birds. Estimates of actual loss have varied, but the total cost could conservatively be at least this amount. Losses in fingerling ponds can be especially severe and have ranged up to 90% in some instances. One estimate places the cost of Mississippi fish farmers alone at over $5.4 million in 1988, which amounted to 3% of the total value of fish sold in the state that year. Aquaculture has become prominent in the U.S. only in the past 30 years, but it is rapidly becoming a significant agricultural enterprise. Last year, the total farm gate value of aquacultural products in this country exceeded $600 million. On the other side of this issue are the birds themselves. One of the most voracious eaters among the predatory birds is the double-crested quamerate, a species that struggled to survive the 60s and 70s and consequently is protected by federal law. This fact raises a difficult question. How do you balance the protection of a valuable economic commodity with protection of a natural resource such as a migratory bird species? There are no easy answers to this dilemma, but today we're going to offer some strategies that will allow the fish farmer to protect his ponds while not harming protected bird populations. With me in the studio today is Frank Boyd with the Animal Damage Control Office of the Animal and Plant Health Inspection Service. Frank, why are the predacious birds such a problem? Well, primarily from the direct consumption of fish. Fish are one of the main items in the food habits of these birds, and if large numbers of birds are around for a long period of time, the cost can be quite significant just in the fish that are consumed. In addition, control efforts are quite costly, very labor-intensive, most of them, and just the outlays producers would have to put out for control programs can be very expensive. Several other things that we don't fully understand that may be a problem such as the potential role for the birds in transmission of fish diseases as well. Well, fish-eating birds haven't always been a problem. What developments led up to this problem? Well, during the early stage of the aquaculture industry's development, most of these bird populations were at low levels due to a number of factors, a large amount of persistent pesticide usage, habitat degradation, but these species have been recovering very dramatically over the last 10 to 12 years. This has corresponded with a dramatic increase in the aquaculture industry as well, and the result of these two phenomena is going on at the same time as presented with the conflicts that we see today. Which birds give you the most problems? Well, that will depend on the area that you're talking about, but for instance, the miniproduction areas of Arkansas and some of the crawfish production areas in South Louisiana, waiting birds would probably be the biggest problem, whereas in the catfish producing areas, the double-crested cormorant would probably be the main one. But overall, probably you could think of the double-crested cormorant, the great blue heron, and the great egret as being the most significant. And they caused the most threat to the aquaculture industry? That would be correct. All of the birds you've mentioned are protected under the Migratory Bird Treaty Act of 1931. What are the implications of this federally protected status? Well, the Migratory Bird Treaty Act protects all migratory birds and all the fish-eating bird species we're discussing are in that. The act prohibits the take or killing of these protected species except under certain conditions. There is a procedure where a depredation permit can be issued when these birds are having an impact on agriculture. When conducting control operations that might involve lethal control techniques without a depredation permit in hand, the consequences could be severe. How severe could that be? Well, it depended on the case, but penalties would range up to $10,000 or six months in jail. That could be rough. Yeah, you need to know what you're doing. Since these birds are protected, what measures can fish farmers take to help themselves get out of this dilemma? Well, there's a wide variety of techniques available which show varying degrees of success. Each situation is somewhat different, but in general, a combination of techniques such as propane cannons, pyrotechnics, recorded distress calls of those birds that would be implicated, used in conjunction with each other, are much more successful than just one scare device by itself. There's also visual scare devices, human effigies, scare crows, as well as barrier systems that can be used to just prevent the birds from getting into the fish facilities. These systems are most generally quite costly and can be time consuming to erect and are generally limited to the smaller areas. Thanks for joining us today Frank. We're going to take a closer look at all of these strategies in a few minutes, but first let's take a brief look at the aquaculture industry in the United States. A significant proportion of the U.S. aquaculture acreage and production is found in the mid-southern states. By far the predominant species, cultured, processed, and marketed in the southern region is the channeled catfish. Channeled catfish are produced in over 160,000 acres of ponds in the U.S., and 89% of that is found in the mid-south states of Alabama, Arkansas, Louisiana, and Mississippi. Other states in the southeast are seeing acreage increases as well. A detailed description of the channeled catfish industry can be found on another southern regional aquaculture center video. Channeled catfish culture in the south, available from your state extension fishery specialist or your local county extension agent. Now let's take a closer look at some of the alternatives fish farmers have to deter avian predators from raiding their ponds. In small systems, physical barriers such as screams, nets, or other exclusion devices can be effective in averting depredation problems. Netting and other enclosures, unfortunately, are typically only economically feasible on small ponds, tanks, or raceways. Enclosures may interfere with harvesting, feeding, and cleaning operations, so they must be constructed for easy setup and removal. Enclosures may be the most effective strategy for controlling bird predation, but in the large-scale systems used in commercial catfish culture, where ponds often average 13 to 17 acres in size, physical covers and exclusion devices are simply not practical and may prove prohibitively expensive. Overhead lines or wires generally will deter most species of fish eating birds if spacings are narrow enough, but as with netting systems, the logistical concerns have not been overcome. Presently such a system would cost as much as $164,000 for a 100-water acre farm. Barrier systems using wire or string in parallel grids with spacing from 25 to 50 feet at varying heights above the water have been tried for deterring cormorants. The concept is meant to take advantage of the relatively long takeoff distance that cormorants generally require. On larger ponds, however, physical problems of spanning large distances are encountered and support posts may need additional anchoring apparatus. In most pond systems, such a grid will be impractical due to interference with seining and harvesting. Additionally, the wading birds such as herons and egrets are not deterred by this method. Electric fencing has reportedly been used with varying degrees of success around pond perimeters to prevent heron and egret predation. Pond bottoms must not slope too gradually from the bank, or wading birds may still be able to fish on the water side of the fence. This system will not work against cormorants, pelicans, or other diving birds. Net fences installed around the perimeters of ponds have often been effective in deterring heron and egret activity in catfish ponds. These birds like to land on solid ground, such as pond levees, before wading into the pond to fish. Unfortunately, most birds quickly learn to avoid the fences, either walking over, under, or simply landing directly into the pond to fish. For best results with perimeter netting, the water should be deep enough, at least two feet or more, just outside the net so birds cannot wade. The most obvious and best method of preventing bird depredation is to locate the farm operation in areas where birds are not likely to frequent and discover the easy foraging conditions in free food. However, this is not always practical, and in the case of the catfish industry, the birds sometimes discover new resources and take advantage of them. A number of factors must be considered when deciding which method or combination of methods should be used to protect aquatic products from bird predation. First, the severity of bird damage will help determine whether control measures are justified economically. In some cases, the cost of deterrence will far exceed the potential loss of fish. Second, the species and numbers of birds using the facility is an important factor, since some species pose far greater damage potential than others. In cases where the problem species is a known high-fish consumer, such as the Cromeret, gray-blue heron, gray egret, or white pelican, even a small number of birds may be intolerable, depending on what species of fish is involved and its potential value. Even in cases where relatively low numbers of birds are involved, it may be dangerous to allow birds to stay since they may attract additional birds to magnify the problem. In Mississippi, for example, producers have operated basically on the assumption that the presence of birds no matter how few poses a threat. Thirdly, physical characteristics and geographic location of farms is also an important factor in determining best control strategies. Size of ponds, raceways, or tanks, along with the proximity to each other, is critical in dictating economic feasibility of certain physical barriers or exclusions. Most birds, for example, can be excluded or deterred from most concrete raceways, tanks, or small ponds by using netting or barrier wires. On most larger facilities, however, and even in some cases on small operations, this alternative is too costly and logistically impossible. The only practical alternative currently available to fish farmers with bird problems and large ponds is to develop an integrated program of deterrents involving scare techniques or other non-lethal measures, along with prudent use of U.S. fish and wildlife service depredation permits. Non-lethal frightening techniques rely upon noise and visual stimuli to convince bird predators that an area is unsafe or otherwise undesirable. Repeated use of these techniques can sometimes condition a local population of birds to avoid areas where they are unwelcome. A number of factors, however, will combine to determine the success of these deterrence programs. These include the bird species, the techniques used, the frequency and duration of use, the availability of another food source, the location of the fish ponds in relation to the roosting and resting areas of the birds, and the general feeding habits of the birds. Although much research needs to be done to determine the best approaches to deterrence, it is clear that a variety of techniques used in combination and alternated often is presently the most effective method of bird control. Frightening techniques can be categorized as either auditory or visual. There are several examples of each. Auditory techniques include pyrotechnics and fireworks, automatic exploder devices, recorded distress calls and electronic noises, and live weapons ammunition. Pyrotechnics include a number of fireworks-type devices. Bird bangers or bird bombs, screamer sirens, also called racket bombs or 15-millimeter cartridges fired from handheld 22-caliber blank pistols. All are fired into the air towards the birds to be frightened. Bird bangers travel 10 to 30 yards and explode similar in force to an M-80 firecracker. Screamer sirens travel about 50 yards, admitting a loud screeching noise. Long-range bird bombs are also available. These noise makers travel about 100 yards before exploding. Shell crackers, another former pyrotechnic, produce a noise similar to bird bangers but are fired from a 12-gauge shotgun. They have greater range than bird bangers, traveling about 50 to 100 yards before they explode. Shell crackers are also easier to use than bird bangers, since they do not require the separate step of loading a 22 blank to propel the device. However, they are more expensive and a 12-gauge shotgun is required. Short barrel single-shot shotguns with brake actions and open-bore cylinders are recommended. Be sure to check the barrel before each shot to make sure the wadding from the previous shot didn't lodge in the barrel. A lodged wand will create a potentially hazardous situation when the next round is fired, resulting in damage to the weapon, personal injury or even death. Also, since the powder in some brands of shell crackers is especially corrosive, a thorough cleaning of the shotgun after each use will prevent corrosion and damage to the gun. The fuse-rope firecracker is a noise device that uses 3-eighths inch or 5-sixteenths inch cotton fuse rope and large waterproof firecrackers. The fuses are inserted into the rope at intervals and the rope is hung from a stake or other object and lit at one end. The rope smolders at the rate of about one inch per 10 minutes and ignites each firecracker, which then falls to the ground and explodes. These can be hung at strategic locations around the ponds and do not require a constant human presence to be effective. There is some fire hazard associated with using pyrotechnics. Care should be taken to assure that they are not discharged onto other explosive or flammable materials when being used. Additionally, eye and ear protection is strongly recommended. Local laws and ordinances may restrict the use of pyrotechnics, so local authorities should be consulted before use. Automatic exploders are devices that utilize propane gas or acetylene and an automatic timer to emit loud explosions and controllable intervals. Rotating mounts are available for some models to vary the direction of the blasts. Using exploders in combination with pyrotechnics and other methods enhances their effectiveness. Birds can become accustomed to the explosions, so it is important to move them to new locations every two to three days and to vary the interval between explosions. If large numbers of birds ignore the noise, it is best to turn them off and to resort to other means of deterrence. Recorded distress calls can be used effectively in conjunction with other methods. The response of fish eating birds to recorded distress calls has been variable, and success probably depends upon the situation in which they are used. Electronic noise generators capable of emitting noises of variable frequency and modulation, loud music, and timed siren devices have also been used with varying degrees of success. Playing distress calls or electronic noises may not show an obvious direct effect on bird predators. However, such auditory stimuli may reinforce other deterrence techniques and may help reduce the amount of effort and expense required when conducting a deterrence or dispersal program. Live ammunition from shotguns and rifles is usually effective in deterring bird activity on ponds. Many farmers use live ammunition because it is less costly than pyrotechnics. However, extreme caution must be exercised, and a depredation permit must be obtained before birds can be fired upon. Rifle bullets can ricochet off water, and many farm situations represent dangerous locations for rifle fire. Shotguns are much safer and less likely to pose long-distance safety hazards. Although many producers use inexpensive small-game shotgun rounds to frighten birds, pyrotechnics are generally more effective because there is a greater variety of sounds and sound combinations, and the noise can be placed very close to the birds. If birds are flushing from several hundred yards, there is generally little difference in effectiveness between shotgun and pyrotechnic fire. Use of any live ammunition also poses the risk of inadvertently killing a bird, which carries severe implications. Visual frightening techniques such as human effigies and scarecrows have proven successful against cormorants. Scarecrows work best when birds are easily frightened by human activity or a vehicle from long distances. They are also more effective when used in combination with noise-making devices. Scarecrows can be easily constructed and should utilize bright colors and movable parts such as swinging or flexible arms that sway in the breeze. Automatic pop-up scarecrows have also been developed. The most popular and effective uses an inflatable human-shaped bag, a battery-powered electric fan, a siren-like noise maker, and a system of timers with a photocell switch. The timers periodically turn on the fan motor, inflating the scarecrow, which rises up presenting a human shape where none was present a few minutes before. Scarecrows should be moved often to reduce bird habituation. If barriers and scare techniques do not work, control lethal methods of bird deterrence may be the only option after birds become habituator to visual and auditory techniques. Although it is unfortunate, it is often helpful to kill a limited number of birds to reinforce the natural fear in the flock. But remember, federal and state regulations must be considered. Necessary permits must be obtained. In some states, both federal and state permits are required, and killing migratory birds without depredation permits is illegal. In most situations, larger flocks of fish-eating birds will be easier to scare from an aquaculture facility than smaller flocks. Producers should expect a reduction, but not necessarily total elimination of bird use on their facility from the use of frightening techniques. There are some key points to remember when using these techniques for bird control. Begin frightening programs before birds have established their regular feeding patterns. The longer they are accustomed to frequenting a facility, the more difficult they will be to frighten away. Try to frighten the birds before they land at the facility. If you can scare them off early in the morning, you can usually move them to other feeding areas. Use a variety of techniques. Do not depend on just one or two devices or techniques. Frequently change locations of passive devices such as scarecrows and explotors, and change the combination of techniques being used as often as possible. Be aggressive. And finally, pursue limited depredation permits if frightening techniques become inadequate. I hope we've given you some insight into the difficult dilemma facing fish farmers in dealing with fish-eating predatory birds. If you would like more information on strategies for controlling bird damage, there are several Southern Regional Aquaculture Center publications that may help you. Publication numbers 400, 401, and 402 deal with avian predators on Southern aquaculture, frightening techniques, and strategies and cost estimates for controlling these predators. All of these publications are available from your county extension agent or from your state extension aquaculture or fishery specialist. Technical assistance is available from the U.S. Department of Agriculture through the Animal Damage Control Office at APHIS, the Animal and Plant Health Inspection Service. On-site evaluations of predation problems, recommendations on control techniques, and sources of scaring equipment and supplies are available. To find the nearest Animal Damage Control Office, contact your county extension agent or call the USDA Animal Damage Control Regional Office in Nashville, Tennessee at 615-7815418. It's always a difficult dilemma when you have to decide between the protection of a valuable economic commodity and the protection of a valued natural resource. But it is possible for fish producers and fish eating migratory birds to coexist with one another. I hope today we've been able to show you some strategies that will allow Southeastern aquaculture and protected migratory bird species to live together. That's our show for today. We'll see you next time on aquaculture today.