Subject: FWD: Economics/Sustainability of production

From: Jack Rowe <[email-masked]>
Date: Fri, 12 Dec 1997 11:09:05 -0500

On 12/10/07, Paula Speraneo wrote:

"With almost 200 subscribers to this list, many not in the U.S., where
economics and feasibility of such a system as ours runs into unthought of
obstacles, I believe we should encourage the exploration of all topics
toward that end.  We're trying to find alternative feed sources in Europe
right now to bring the system operating costs more in line with the
economics of Romania."

I agree wholeheartedly! Economics of production is an extremely pertinent
topic in these days when ecosystems and resource bases are under serious
threat. In the USA, the energy which goes into producing farm-raised
catfish FAR exceeds the energy which can then be gotten from the fish. This
seemingly impossible situation is made possible by fossil fuel inputs in
the form of commercial food production and processing, aeration, water
pumping, pond materials production, etc., etc. 

In many -- probably most -- parts of the world, putting more into a food
production system than can be gotten out is simply not possible. Dan
Hemenway's interesting comments about the caloric impracticality of feeding
good meat to fish and the practice of feeding maggots to fish are not
considered unrealistic in Asian fish production systems. In Asia, fish
ponds receive much of their necessary phosphorous and calcium from animal,
human and bird manures, with animal pens and even latrines placed where
effluents reach the shallow, low-trophic (phyto- and zoo-plankton
producing) areas of fish ponds. Economically-important carp have evolved in
concert with dense human populations to survive in polluted waters with
very low dissolved oxygen levels in which catfish, for example, could not
survive. Carp exist for highly-efficient production of food from every
trophic level in a pond, from vegetation-eaters to plankton-eaters to
carnivores (the common bass/bluegill/catfish trio is our southern-US
trophic-ladder equivalent, though vegetation is, sadly, not well-utilized
by this group). 

In Europe, also, many alternative ways of maintaining the aquatic food
chain are practiced, including fertilization with animal and vegetative
'manures'. Ponds are commonly drained during winter months and planted with
edible crops or green manures to reclaim excess nutrients from bottom mud
(the practice of drying pond bottoms can be quite beneficial to pond
health, helping to control many parasites and diseases of fish). In eastern
Europe especially, economics of production dictates that energy out exceeds
energy in, and Paula mentions efforts to adapt scientific production
methods to the extremely 'earthed' economy of Romania. 

These approaches to production, far from being crude, are far more
'scientific' than our methods of producing 100 calories of fish (or corn,
or beef) with several hundreds of calories of high-protein food and energy.
It doesn't take a calculator, a slide rule or even an abacus to figure out
putting more energy into a system than comes out is a failure of sorts,
even if the fish tastes great fried in cornmeal. Using vermiculture systems
to convert human food wastes into high-quality terrestrial fertilizer AND
nutritious fish food, all in one fell swoop, is an excellent move toward
sustainability of production. Cleaning polluted water by using it to water
and fertilize terrestrial crops is another good idea. 

John Todd was mentioned in connection with water purification by biological
means, and his book "Living Machines" discusses this idea in depth.
Dwelling-size waste-purification systems turn out extremely high-quality
water and produce significant amounts of vegetables and fish.

An excellent, science-based fish farming resource which outlines intensive
US fish production methods as well as alternative, low-input,
highly-productive fish raising methods as practiced in Asia and Europe is
"Textbook of Fish Culture: Breeding and Cultivation of Fish" by Marcel
Huet, published by Fishing News, London, 1972. To me this is a "must-read"
for anyone wanting to establish a sustainable fish production system.

I'm really enjoying the expertise and provocative, innovative questions and
ideas from of the members of the list, thanks! Those who were the
'crackpots' yesterday are the visionaries tomorrow!

Jack Rowe

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From: Jack Rowe <[email-masked]>
Date: Fri, 12 Dec 1997 11:09:11 -0500

>Jack Rowe wrote:

> In Asia, fish ponds receive much of their necessary phosphorous 
>and calcium from animal, human and bird manures, with 
>animal pens and even latrines placed where effluents reach 
>the shallow, low-trophic (phyto- and zoo-plankton producing) 
>areas of fish ponds. 

>>Lloyd Prentice wrote:

>>I have read that some of these systems are implicated in the 
>>evolution of influenza viruses. Anybody know more?

I suspect, without knowing many specifics, that your point raises a valid
health concern, Lloyd. In fact, influenza might be only one of the
possibilities arising from careless handling of fish raised in direct
contact with human and animal manures. E. coli, cholera, salmonella, etc.
come to mind... thorough cooking would be a necessity in these situations,
as it is with chicken 'manufactured' in the US.

One of my two major points was the desirability of careful use/reuse of all
'waste' products -- which can be seen as either resources or pollution.
When we treat manure as pollution, we pay to have it 'removed' (to where?).
Wastes treated as pollution tend to accumulate and, in fact, begin to act
as pollutants. When we call a waste a resource, we are often able to find
productive uses. The material may be the same in either case, but our
perception by itself can change that material from a liability to a
valuable resource -- or vice versa.

The other point is that, each time we move a step up the trophic/food
ladder, a great deal of energy is used. Food-to-meat conversion factors
tend to be 20% at the best and are usually much lower (fish are very
efficeint at food conversion, happily). We will always get the biggest
'bang for our buck' if we feed at the lowest point on the trophic ladder
that we can. In general terms, feeding high-protein food to catfish (which
are scavengers), for instance, is for this reason not 'economical' when
viewed in holistic or ecological terms. Intensive feeding in aquaculture or
agriculture raises production dramatically, but it does not necessarily
raise cost-effectiveness of an overall operation due to the law of
diminishing returns (land and materials costs, of course, force production
to reach toward the highest compromise between intensive production and
least input, fueling some degree of energetic inefficiency in return for
financial viability).

Feeding at the lowest trophic level is why ponds are most-economically
fertilized with calcium and phosphorous... these are critical elements in
the production of phytoplanktons and zooplanktons, which form the base of
the food 'pyramid' in aquatic systems (economically important herbivorous
fish being fairly uncommon -- unless we call phytoplankton eaters
herbivores). Manures are rich in phosphorous, and often rich in calcium. A
great deal of production can come from feeding manures to the planktons,
whereas few of the animals higher on the trophic ladder will eat manure to
advantage (a valid fact pointed toward by Lloyd). Manures are ubiquitous
and generally more common than natural sources of high-analysis nutritive
minerals.

However, manures are an energetic step up from minerals and are also rich
in nitrogen, which is almost never a limiting factor in fish production and
is often a harmful pollutant causing turbidity and lowering of dissolved
oxygen levels. Perhaps manures are best 'composting' during biogas
(methane) production and then used as fertilizers in terrestrial
applications. Conventional sewage treatment produces biogas... the
difference is that the methane is seen as pollution an is not captured for
use (an electrical generation plant in Stanton, CA uses human sewage to
produce the gas which fires its generators). Manures can in fact be
safely-recylced in a number of ways which use their nutritive value to
postive effect instead of purposely dissipating it at considerable expense.

Producing our needs at the lowest economic, energetic and ecological costs
is the critical next step in aquacultural and agricultural systems (as in
other systems). We'll continue to learn more efficient ways of, as Paula
put it, "...raising fish and plants in a synergistic system... to produce
products we could consume and sell as "safe", while using a more natural
method of fertilization...". In the process, we'll have to explore many
ideas and look at our energy and materials cycles in a new light.
Eventually we will come up with ways to produce our needs without relying
on fossil fuels to power the necessary cycles, and without creating
pollution from materials which could be used productively instead. As one
definition of sustainability puts it, "Sustainability is meeting our needs
without endangering the ability of future generations to meet THEIR needs".
A worthy goal we're all in agreement with. 

Jack Rowe

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From: Jack Rowe <[email-masked]>
Date: Fri, 12 Dec 1997 11:09:11 -0500

Jack Rowe