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4 Major Aquaculture Production Systems



aquaculture is the reproduction and growth of aquatic organisms and a controlled or semi controlled environment there are many species of fish shellfish crustaceans and aquatic plants produced by aqua cultures around the globe scientists estimate that there are approximately 300 species currently being produced and they're finding many more potential species each year hi my name is David Klein and I am an aquaculture specialist with the Alabama Cooperative Extension system at Auburn University this presentation will provide an overview of four common types of aquaculture production systems that are used by today's aquaculture ist's the systems include ponds cages raceways and recirculating systems there are different ways to measure the intensity of production systems but for today's presentation we'll use the amount of human intervention with an increase in system intensity the amount and cost of inputs rises as does the required management skill each system has its own set of advantages and drawbacks so it's important to match the best type of system with your specific location and species whenever you place a large number of aquatic animals in a restricted environment it's up to you to make sure that you provide the basic requirements for them to live and grow these requirements may vary from species to species but all culture systems must meet the basic requirements in order for the fish to thrive can you guess what they are did you guess they include water oxygen food and a way for the fish to get rid of waste for fish their waste goes directly back into their environment and aqua cultures must find a way to deal with this waste ponds are the most commonly employed and least intense aquaculture system ponds are enclosed water that most commonly have two three or four sides depending on the topography of the land where they're in production settings ponds are often laid out so that they can share levees sharing levees reduces the amount of dirt moving during the construction process which helps reduce cost and it also makes the most efficient use of the available land in some countries there are areas that have high concentrations of production ponds even very close to urban centers water to fill the ponds can come from wells rain runoff Springs streams or other bodies of surface water well water is generally the most consistent and reliable but can be expensive to move the water with pumps in Alabama most of the water is captured rainwater but in Mississippi most of the pond water comes from underground wells in most ponds the oxygen is supplied by microscopic plants called phytoplankton or algae it is these tiny plants that supply most of the available oxygen through a process called photosynthesis the amount of oxygen available is closely tied to the density of algae during the day the plants remove carbon dioxide from the water and produce oxygen but at night when the Sun Goes Down the plants begin to respire which consumes oxygen and releases the carbon dioxide back into the water if you were to draw a graph of the daily oxygen levels it might look something like this during the sunlight hours the oxygen level is rising but at night when the algae are respiring the oxygen levels decrease some oxygen for the fish in pond production comes out of the air and a process called diffusion in this process the oxygen molecules move from a region of higher concentration in the air to a region of lower concentration in the water sometimes especially in the summer and often at night there's a shortage of available oxygen if this happens the farmer uses mechanical aerators to increase the oxygen levels these aerators get the oxygen into the water by put water in the air like with these paddle wheels or air into the water using diffusers or other types of aerators without enough oxygen fish will get stressed and can even die in short period of time food for the pond fish is generally provided by the farmer in the form of floating pellets fish food may contain plants like corn and soybeans fish meal and a variety of vitamins and minerals the formula and form of the feed varies with the size and species of fish trucks with feed blowers may be used to help spread the feed across the pond surface spreading the feed across the pond gives the fish better access to the feed and reduces competition among is the primary waste that fish produce and even relatively low concentrations in the water can be stressful ammonia comes from the fish waste as well as uneaten feed in pond culture much of the ammonia is taken up or assimilated by the phytoplankton the remainder is broken down by bacteria into less toxic forms in a process called nitrification cage culture is the next level of intensity the advantages of cage culture include the ability to easily stock feed treat and harvest the fish the disadvantages include increased vulnerability to predators and the rapid spread of disease should one occur cage culture generally involves taking all the fish you would normally allow to roam free in the pond and put them in one place cages can range in size from one cubic metre for a small cage to a large as 100 cubic metres in fresh water you can grow a variety of fish in cages including tilapia catfish striped bass and sometimes trout cages are generally constructed from either a soft material like nylon net or a hard material like extruded plastic or vinyl coated wire stocking rates and fresh water can vary from five to twelve fish per cubic foot and under ideal conditions it's possible to grow up to ten pounds of fish per cubic of caged space see cages that are used in the ocean are much larger and can measure up to 125 thousand cubic meters which is roughly 75 meters by 75 meters by 20 meters deep they have to be very strong to protect the fish from predators and damage from the rough seas benefits of sea cages is that they can be moved around if necessary and expansion the operation is relatively straightforward the downside of sea cages is that the aqua cultures have little control over the environment including the weather water quality and potential for disease outbreaks oxygen for the fishing cages comes mostly from photosynthesis but it can be supplemented by aeration cages are not typically aerated but depending on the movement of water through the cage and through the mesh to bring in fresh oxygenated water because the fish are confined in the cages there's little if any natural food available therefore the Fiji's and cage culture must be high-quality and nutritionally complete when caged fish feed vigorously they may splash and throw feed out of the cage some cages have a ring of smaller mesh material around the top called a feed ring that will help keep the food in the cage until the fish can eat it waste created in fish cages generally falls through the bottom of the cage or is removed by the water circulating through the cage the pond outside the cage still serves as the bio filter and the ammonia is taken up by algae and broken down by bacteria much the same way as it is in pond culture raceways are the next level of production technology raceways are rectangular structures built above or below ground where the water flows in one end and out the other raceways typically have a length to width ratio of 5 to 1 or more and may be constructed of cement fiberglass or even wood fish culture and raceways requires large quantities of high quality water preferably supplied by gravity flow from artesian wells or water coming from a higher elevation raceways can be used for the production of both warm water fish such as tilapia or cool water species but it's most commonly associated with the production of trout and there are many trout farms in Idaho where they have lots of high quality freshwater flowing from the mountains the quantity of fish that can be grown at a Raceway is dependent on both the quality and the quantity of water available depending on the water chemistry it is possible to grow between 30 and 100 pounds of trout per gallon per minute of flow for example if a Raceway has 1,000 gallons per minute of flow available it can support 30,000 to 100,000 pounds of production on an annual basis oxygen in the raceways comes in with the freshwater and may be increased or maintained by letting the water fall from one Raceway segment to another the following water causes splashing that assists in the diffusion of oxygen from the air like the fishing cages fish and raceways do not have access to any natural foods so they are totally dependent on the prepared diet for all of their nutritional needs feeds for these systems must be high quality and are typically more expensive than feeds for pond raised fish the feed is often supplied automatically to the fish into Raceway several times per day by mechanical or demand feeders raceways are designed to be a single pass flow through system that sweep away fish waste and any and I can feed downstream and out of the fish culture unit some raceways have a solid settling area at the end of the Raceway and large Raceway operations often require settling ponds or other waste treatment facilities before the water can be released into the environment recirculating aquaculture systems no matter how small or how large are considered to be among most intensive forms of aquaculture the lure of these systems is that they can be located almost anywhere and do not require as much water as the other production systems it is possible to grow up to one pound of fish per gallon of water in these systems but they require significant energy equipment and managerial expertise and all of these requirements add to the cost of the product the systems contain a number of components that include the culture tank a filter to remove solid waste a biological filter to remove dissolved wastes like ammonia oxygenation equipment carbon dioxide removal and a way to sterilize the water because of the heavy biological load on the system recirculating systems require the continuous addition of oxygen depending on the level of intensity and complexity of the systems air or pure oxygen may be used different devices ensure that oxygen is maintained at an adequate level if power is lost in one of these systems the fish can die very quickly from lack of oxygen so backup plan is essential efficient recirculating aquaculture systems require high quality feed that meets all of their nutritional requirements like the fish in cage culture and Raceway culture these fish do not have access to any natural foods waste removal is an integral component of recirculating aquaculture system there is usually a mechanical filter like a screen filter a drum filter or a bead filter that removes solid wastes and a biological filter that removes the dissolved waste biofilters generally contain beads balls or other media that have large surface area to volume ratios where bacteria can grow these bacteria help break down the ammonia into less toxic nitrate through the nitrification cycle okay let's quickly review the technologies we've seen ponds are the most commonly used production system and rely heavily on natural processes to remove waste and provide oxygen good catfish farmers can produce six to eight thousand pounds of fish per acre or even more cages can be used in existing bodies of fresher saltwater to confine and grow fish in large numbers waste is processed by the larger body of water and it is critical to maintain water movement and circulation throughout the cage confinement has its advantages but the high densities of fish increased the risk of disease or other problems in these systems it's possible to grow five to ten pounds of fish per cubic foot of cage space raceways require large volumes of water to maintain water quality and there are relatively few locations where this type of resource is still available the amount of fish that can be grown is directly correlated to the quantity and the quality of water it is possible to grow up to 30 to 100 pounds of fish for each gallon per minute of flow recirculating aquaculture systems are the most intense form of aquaculture and rely heavily on external power and mechanical processes to maintain the water quality it's possible to maintain loads as high as one pound of fish per gallon of water with continual filtering and the addition of oxygen these systems offer the highest potential reward but also the greatest risk of failure in addition to the four traditional culture systems that we've looked at scientists are developing new integrated systems that incorporate the best characteristics of each technology examples include in pond raceways floating raceways and partitioned aquaculture systems but that's a story for another day I hope that you've enjoyed this presentation and are inspired to learn more about these technologies if you'd like more detailed information please have a look at the included supplemental readings or if you're viewing this online please visit our website at WWE and have a great day

7 Comments

  1. Martha Cecilia Manjarres

    hi everyone ,if anyone else wants to uncover aquaponics course try Morundan Total Aquaponics Mastery (do a search on google ) ? Ive heard some amazing things about it and my cousin got great results with it.

    Reply
  2. bong Scott

    I hope to have the 5 soon new closed off shore system working on final spec's know 50m circumference 40m depth 70,000m3 and full fish tank system I love pushing maths☺😊😀😁😂😃😄😅😆 and no waste as it has its own skimmer and you can either sell or treat waste to make nitrous oxide?

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