From CU-Boulder News:

The completed project will be a bioregenerative food system that will grow, harvest and compost a variety of plants. Bioregenerative systems support life by simultaneously revitalizing the atmosphere, purifying water and producing food for consumption.

It started with this article, which caught my eye a few days ago. I thought it was awesome, was slightly jealous, and then it drifted to the back of my mind to percolate with all the other things I like to think about.
This morning, as I was laying in bed awake and bored because it was far too early to get up… the idea of this article made sweet sweet love with the idea of Aquaponics and the idea of colonizing Mars… and gave birth to some fun wild speculation.

I spent my entire Sunday morning on these thoughts. I regret nothing.

One of the first problems I thought of was the difficulty of transporting fish on a space ship… but I also remembered once reading about fish who’s eggs survive drying. So I looked that up.
Turns out I was thinking of killifish, and some people report hatching eggs after two years of storage - so the 6month trip to Mars wouldn’t be too big of a deal - especially since killifish eggs seem to do fine in space. Another advantage of killifish is how well they adapt to less-than-optimal water quality, which might happen in a colony.

Problem #2, These are not great eating/aquaculture fish. Killifish tend to be quite small, the males tend to be territorial, and most species eat invertebrates (animal-based food) - which would be harder to supply in a space-colonizing situation with limited resources. 
These problems can be solved by another of the killifish’s tendencies - to hybridize readily. Put together a breeding program - add in algie-eating killifish, larger killifish, and non-territorial killifish. Select for large fast-growing calm fish who do well at high stocking densities, and on plant-based foods. Select for eggs that store well for longer periods of time. -basically, breed yourself the tilapia of killifish. Even if you could never make a large killifish, colonists could probably get used to eating them like sardines.
Alternatively, use genetic engineering to make the killifish of Tilapia - a tilapia who’s eggs survive drying. While I feel ishy at best about genetically engineered organisms on Earth, I find I have no qualms about sending them to be eaten on Mars where there are no (known) biological systems for them to disrupt.

One thing that I keep coming back to when thinking about raising fish on Mars or any other colony is that you have to bring everything with you. Unlike on Earth you can’t just toss some water in a pond and expect the nitrogen cycle to establish itself - the correct bacteria just wouldn’t be present. Same with algae. What looks like spontaneous generation just wouldn’t generate on a sterile planet. There would have to be some research to find out exactly which algae and bacterias were necessary to bring with to keep the system healthy. 

The system that kickstarted this thought process is seems to be very automated. There may be reasons for this that I don’t know since I am (sadly) not a scientist, but if I were designing a bioregenerative system I would try to keep it as simple as possible so there were the fewest possible things to break down. Most aquaponic systems seem to get by with just one or two water pumps, and I fail to see why a system on Mars would need to be much more complex.

After spending some time thinking about the fish, I then started to think of the other animals… but I didn’t get too far. It seems like it would be beneficial to have frozen embryos of various domestic animals and grow them when the colony has grown to have the space for them - but sadly wikipedia tells me that artificial wombs are still a long ways off - so our intrepid Mars colonists might have to be pescatarians.

These are my thoughts.

Until next time-

-Z