13.2 The case for aquaculture
13.3 Some factors affecting total useful yields
13.4 Choice of fish species (varieties, food, health) and factors in yield
13.5 Fish pond configurations and food supply
13.6 Farming invertebrates for fish food
13.7 Channel, canal, chinampa
13.8 Yields outside the pond 13.9 Bringing in the harvest
13.10 Traditional and new water polycultures
- Bill's excited about it
- he's also excited about this gate contraption that regulates water levels
- he's way more excited about the general infrastructure, and tying together functions like compost re-processing, than about specific fish. Or local specifics in general.
He does mention differences between fish, and the importance of temperature.
Either Bill or I are confused about 'chinampas' - I thought they were floating planting beds made on reed mats, and he's describing them as the raised planting beds fertilized by piles of lake-harvested reeds and debris.
Let's see who Wikipedia agrees with:http://en.wikipedia.org/wiki/Chinampa Bill wins this one!
Whether or not they 'float' between their stakes (which would not be a bad idea for a tidal river, or one prone to periodic flood discharges from upstream dams, but might require a great deal more engineering than a simple raised bed), they are a land-based creation more than a floating one.
The folks I've heard from who are setting up aquaculture often contact me about ways to heat the water.
I think researching climate-appropriate fish is Step 1.
If your climate will require beaucoup heat input into a double-walled greenhouse to keep everything alive, you are growing the wrong species mix for your climate.
We also have a lot of problems with invasive species like ...
which Bill mentions several times as a great multi-function fish.
We had to institute a 'no-live-capture' policy at summer camps, because kids who caught a fish while fishing are uber-tempted to release it again in the 'wild'. Accidental release through waterways is also highly likely if you are in any location with enough flowing water to make aquaculture an affordable proposition.
If anybody wants to pick Ernie's brains about fish-rearing for cold climates, he has a mouthful to say on the subject.
If he could write, I'd get him to write a book on it.
If you know your local fish - what substrates they require for reproduction, what temperature tolerances, whether you will need to feed them 10 times their weight in high-quality protein, whether their life cycle involves transition from salt to fresh water (hard to duplicate in captivity, but similar species may be locally viable e.g. salmon and steelhead vs. kokanie or trout, landlocked freshwater salmonids) ... then you can design around them.
A good local fisherman who's committed to long-term sustained fisheries (like Ernie was raised to be) will know these things. Most sport fishermen and sportsmen also know a great deal about preferred habitat and food (bait) - Ducks Unlimited has been a major force for wetland restoration, although sometimes with dubious care for invasive species as long as "Ducks Love It."
We have a pond, it was a natural upland pond but then was scraped off, reshaped, and finally covered in black plastic, unsuitably thin black plastic that is now full of holes and thistles, and is even growing a moss-lichen 'crust' over parts of its windblown soil deposits. So we kinda have an open slate here.
I'm excited about cultivating native reeds for fiber, and possibly for use as insulation.
Every time I get a suggestion of what to plant during the 'restoration,' I go out there, and I find a remnant population that's already there. I am 'rescuing' clumps of existing vegetation and trying to get them to spread into newly opened-up areas. Still hoping for wapato, camas, other edible liles (mariposa?)... those I might have to import and see how they do.
Waterways like all wilderness are extremely protected, and often contain vestigial populations of endangered species. Many wetlands have been drained or deepened for various reasons, with horrible consequences in hurricanes and floods.
Please, please, please research your local wetland habitats, and try to restore what was there and leave good wildlife access to the few remaining open water areas.
If you can create an integrated pond-garden system that also discharges superior water to wildlife habitat, that's a lovely idea.
But don't be tempted to do what so many other landholders have done, and bulldoze the swamp because its "wasteland." It is a highly developed waste-processing land, and bulldozing it can leave unstable slopes, soil problems, and invasive species problems that can persist for decades or generations.
State bureaus charged with wetland protection have fairly restricted protocols - for example one team we worked with were not allowed to include deep water spots in a "wetland," and did their planting all in one go without much interest in Ernie's carefully-researched myco-filtration recommendations to pull potential toxins from incoming street runoff. Oh, well. They do their thing.
The state agencies often do have a good sense of the history of past abuses, and definitely have lists of species considered invasive.
If you just add any non-native "game" fish (which includes cross-continental transplants) to their lists, and don't emulate their past sins in turning over local fish nurseries to exotic sport fisheries, you should be better off than you started out.
It's not just Bill I'm cynical about!
Even if you create your own pond, and don't think the fish will ever escape, I would favor stocking it with relatively local varieties. There's always herons, osprey, bears, and those little monkeys we call 'kids', who can carry a struggling fish a fair ways before they let it escape.
We get the oddest populations of hybrid ducks in the parks.
I do think kettles for fish escapement are a nice part of wetland variety.
I think invasive plants are infinitely to be preferred to spray-treatment of damaged wetland areas, and stabilization with non-invasive plants better yet.
I think a shovelful of muck from someplace nearby and healthy may go a long ways further than trying to memorize native plants - but be sure you can recognize 'healthy,' because if your place is and theirs isn't, you've just taken a big leap backwards.
Two very grand examples of aquaculture / geese culture:
How I Fell In Love With a Fish, by Dan Barber
(reviewed here: http://www.transitiontowns.org.nz/node/2393; I originally saw it on Ted Talks here: )
Describes a large-scale shrimp/fish plantation where the ecosystem has no external inputs, and they measure the health of the system by the health of its predators (cranes and flamingos or some such), as contrasted with "feeding chickens to fish" in offshore fish-farms.
The same author did similar presentation, A Foie Gras Parable, about a farmer whose geese are so happy that they gorge themselves without force-feeding on such a distinctive mix of flavorful plants that the resulting liver pate doesn't need to be seasoned - it's already flavored. He does not need to 'boost production,' because the worldwide demand for his product - at prices far above 'premium' - far exceeds the stocking rates that his domestic and wild geese naturally enjoy for optimal results.
As geese are also a wetland species, it seemed relevant.
One of the fundamental and little-talked-about issues in fish farming is flavor.
The fish that can tolerate crappy, low-oxygen conditions and eat anything (carp, tilapia) tend to taste a bit like mud.
They taste even more like mud when raised in crappy conditions: no aeration, warm water over-saturated with nutrients, depleted oxygen especially at night when the catfish have to 'burp' air to survive.
Ironically, because tolerating crappy, oversized-fishtank conditions is a major convenience factor in the industry, these are among the most popular fish to raise.
The 'tastiest' fish tend to be those that take a lot of big, cool, spacious, flowing or highly oxygenated water: salmonids, slow-growing sturgeon, tuna. These are apex predators and need substantial quantities of other fish (or chicken, as in the ill-advised counterexample above) to reach full size. Not always fond of crowding, either. Downright finicky.
The exception that I'm aware of is crustaceans - crawdads and crabs are excellent scavengers, will eat up things that otherwise make the water dangerous (corpses etc), and always taste delicious.
I'm not encouraging raising apex predators as a primary market crop - just encouraging you to sample before and during any aquaponics design project. If you don't like the flavor yourself, you had better have a ready-made market because you will have a hard time selling it with your personal conviction.
It may be useful to consider 'finishing' any portable fish in a cleaner environment with a sweeter feed, like for example putting catfish in a bathtub of pure spring water and feeding them corn for a week or so does for the flavor about what feeding pigs on grain or fruit does. Clams are often 'purged' in fresh or salt water different from what they grew in, to rinse out sand and so on.
A novel I read featured an island consulate, where they happened to have ponds or tanks that are essentially just (relatively clean) holding pens for captured fish, turtles, etc. They can be stocked and allowed to grow until wanted for dinner. A natural pond can keep stocked fish healthy much longer than a tank, if the species are a good match. Presumably someone was responsible for checking on them, and possibly feeding them, but that didn't figure into the story.
I suspect 'tending the fishpond' would be an ideal job for the right boy at the right age. Even if all the fish did get 'sampled' the first year, just to see. Beats the heck out of reaching under chickens, if you're old enough to be sensitive about 'boy' and 'girl' jobs. Have not met as many fish-crazy girls, but I know quite a few who wouldn't mind sitting by the pond with a journal a few days each week.
As a pond seems like a hopeless dream in my climate, I read this chapter as a lesson in applying principles stated throughout the book:
using complex geometry to create edge effects (esp see Figure 13.17);
adaptive choice of species to suit the conditions, not vice versa;
stacking functions, especially efficient siting of waste streams;
careful assessment of input costs, polycultures to reduce feed costs of market species;
needed analysis of the input labor requirements (heaps of monitoring in aquaculture--seems like a brittle system with little tolerance for sloppy work);
design protection for worst case incidents;
designing the plan to succeed via local marketability.
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I cannot believe that he seriously mentioned cultivating cockroaches. I will not ever mention that small section to anyone remotely interested in learning more about permaculture. Like humanure, it belongs in the list of advanced topics of permaculture best discovered well after the journey to sustainable self-sufficiency has been launched. No one is ever ever going to say they took up permaculture because they always thought they wanted to raise roaches.
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I was struck by two quotes:
"The often rigid (and very recently monocultural) inhibitions of farmers are not yet evident in water cultures, where the advantages of polyculture have been recognised from the beginning."(p 459)
"...but whoever we spend a few hours analysing a more efficient or begin configuration before we call in the bucket or dredge, our return may be many times that of the Euclidean or 'straight' designer. The yield goes on for years and years, while the digging of the pond is a single event." (p 482)
The yield goes on and on, so invest well in the initial infrastructure--a call to action that deserves more prominence throughout the book. Mollison seems to have no aversion to bringing out the big machinery when called for in the beginning, neither should I. In other words, suck it up and spend some cash instead of trying to cheap out. I don't have a thousand years to spend digging the terraces, and I don't need to feel perm-guilt for using some diesel to put in the backbone of my system.
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Growing up in the west, living near open water, even a tiny pond, seems like a richness beyond compare. How to make it happen here in an ecologically acceptable way with the political barriers (essentially no rainwater collection) peculiar to my state? Like I said in an earlier chapter, creating amphibian habitat here would be the ultimate metric of success for our project. The solution is to be found in the problem, if I just keep pondering it.