Tag Archive for Aquaponics

Saltwater Aquaponics

One thing I will be doing before Christmas this year is to set up a saltwater aquaponics system at home (I already have a 6,000L freshwater system). Only small as a proof of concept, but then to see with what I can do with it from there.Steamed Samphire & Lemon

Fish types are easy as both trout and barramundi can live in full seawater and I can also get black bream fingerlings if needed.

Plants then need some consideration. Obviously I’ll be putting seaweed into the system, and this will be an Ulva variety of some description. However, seaweed on it’s own is unlikely to be attractive to a wide audience.

Hence I’ll need some sort of growbed to be able to grow non-seaweed type plants. Samphire (see the photo) is the first thing that comes to mind. The growbed will also provide me with some or all of my biofiltration. If I can find a number of plants that will be of interest, then increased growbed volume can be my entire biofiltration, if not I’ll hook up a moving bed filter with some Kaldnes media in it.

Better start researching samphires in Western Australia !

Why Seaweed

I’ve had a life long interest in fish and aquaculture, so that’s quite a few years. Ten years or so ago I recognised (after many others before me) that aquaculture as we practice it now is not sustainable, for two reasons;

  • the fishmeal component in aquaculture feed (i.e. wild-catch fish to feed fish), and
  • we don’t know enough about fish and their environment to successfully raise them in the monoculture approach we currently take

There are multitudes of people far smarter than me investigating other options for sourcing protein and omega oils into fish feed and, fortunately, it’s not something I’m particularly interested in anyway.

However, the second point does interest me on a number of levels.

So that got me thinking “What can we do to avoid having to go through a couple of thousand years of domestication, as with livestock and plant crops, to gain the knowledge to successfully farm these things?”

That eventually led me to the discovery of aquaponics and then Integrated Multi-Trophic Aquaculture, or IMTA.  Both of these approaches to farming fish take a more holistic view and attempt to replicate an ecological system rather than the intensive farming of one species.

In the case of IMTA that, in a very brief description, involves the inclusion of filter feeders (oysters, mussels, etc) and nutrient strippers (seaweeds) to begin to replicate an ecosystem.

Now, there’s plenty of people looking into the farming of fish and shellfish but significantly less looking into growing seaweed. And the more I investigate the more I am fascinated about the little bit we do know about seaweed and just how much more we don’t – yet it’s an integral part of the IMTA puzzle, and an economic crop in it’s own right !