What is Aquaculture in relation to Aquaponics?
There are many different forms of aquaculture and not all are suited to aquaponics. So what is aquaculture and how does it differ as part of an aquaponics system. There has also been a lot of media coverage of the environmental impacts of aquaculture, but this is also a lop-sided view, ignoring the various sustainable alternatives now growing in popularity. This page is intended to give you a general overview of the subject with references to more detailed information if you are interested. A brief History of AquacultureThe most prevalent form of aquaculture today is oyster farming and this practice can be traced to the Ancient Romans. Then as now, the production of shellfish like oysters, mussels and abalone (as well as crustaceans like prawns and shrimp) predominate because wild stock are often too sparsely distributed to make fishing an economic alternative. Another feature of early systems is that they focused on only a few, low-value 'staple' species that could be handled cheaply in large numbers. This continues today - again for economic reasons. However, the advent of trout and salmon farming, together with growth of Aquaculture in Australia, has seen a trend develop towards smaller-scale operations devoted to a much larger number of high-value species - especially where wild stocks are becoming depleted. The most recent trend is in multi-species or polyculture systems. In fact, all aquaponic systems represent a form of integrated polyculture. If you are interested in a more detailed description of the history of aquaculture, Click Here. What is Aquaculture in aquaponicsMost forms of aquaculture use "Open systems" where water flows through continuously. This reduces the need to worry about water quality (although water quality downstream of the operation can be of concern). However, the main versions we will be looking at here are the "Closed" or recirculated aquaculture systems. Of course there will also be some things that will either be done differently or otherwise not included in more conventional "Recirc" systems. These relate to our objective of developing ecologically-based and largely self-sustaining aquaponics systems and so we will not be talking about pressure filters, oxygen generators, geothermal temperature control and other high-tech "Whiz-bangery" that is now so prevalent. Conversely, this means we will spend more time looking at things these bits of technology aim to manage in more convenient and almost unconscious ways (for the operator of course). They include an number of factors that other aquaculturists might never consider, such as:
Other things like salt levels and pH will largely take care of themselves if everything else is right. OK, so we have spent some time talking mostly about what aquaculture is not - in aquaponics, but what is aquaculture in this context really? Like the ancient aquaculturists, we will be dealing essentially with fish holding and 'purging' systems, where little or no growth is involved. We will also be dealing with polyculture systems. For example, my system has both fish and Yabbies, and later perhaps also some freshwater mussels. The last two are intended to help with recycling of nutrients through the sediment that develops on the bottom rather than be food (although if I can find a way to culture freshwater pearls in the mussels - that could be cool! Aquaponics is also aquaculture linked to plant production as part of the bio-filtration component of the system. However, rather than go on indefinitely here, you should tackle each of these subject individually. You can use the links below to find out more. Further Reading and Useful Links
What is Aquaculture Water Quality all about?
Plant growth in Aquaponics
Garden Ecology
A Useful Commercial Aquaculture Portal
A report on Sustainable alternatives in Aquaculture
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