Re: RFP - aquaculture instructional materials
> >I have no special knowledge of aquaculture, but I confess I am
> >suspicious about it as a form of "sustainable agriculture."
> >are we talking marine or freshwater aquaculture? If marine, then
> >how can an intensive managed production system (aquaculture) begin
> >equal the immense natural productivity of the oceans, which
> >solar energy on every square foot. When I asked someone about
> >marine aquaculture feedstock, I was told they are fed rough fish
> >fish waste from deep-sea fishing, plus grain produced on the land.
> >I didn't get an estimate of the ratio. The point is, shrimp or
> >or whatever are most certainly NOT subsisting on the solar input
> >associated with the surface area of their confinement space. So it
> >like maybe the growth of marine aquaculture depends in part on
> >the continuing mining of the wild marine resources AS WELL AS
> >agriculture. Please, TELL ME IT ISN'T SO!
> >Okay, so how about freshwater aquaculture. In a farm pond,
> >with a whole-farm production system, aquaculture sounds good.
> >include residues and wastes as well as maybe some human-edible
> >from the farm.
> >But I am guessing that intensive catfish, trout, tilapia, etc. are
> >to be mostly fed from grain, produced in industrial farming
> >Again, please TELL ME IT ISN'T SO.
> >I'm not claiming to be informed, I'm just trying to be a skeptical
> >of ideas. What really sets me off is that this RFP talks about
> >"aquaculture AS sustainable agriculture," not "aquaculture IN
> >I hope this comment will lead someone to share insights into these
> >concerns I have with aquaculture.
A farm I am associated with has incorporated a saltwater fish farm
into its sustainable practices. The saltwater ponds were engineered
out of mudflats in front of the mangroves, working with natural
contours, tidal flows, etc. One man did this with one digger, the farm
covers 5 acres.
A system of valves works with natural tidal flows and a channel
running partway round the entire farm feeds the individual ponds which
are all graded to allow different depths for different sizes of fish
and for draining when necessary.
The main species farmed is the grey mullet which were bred from spawn
caught from the breeding ground in the mangrove - only a small
percentage at any one time were taken - one man and a large
'butterfly' net was all that was involved.
The initial foodstuff was meatmeal which is a natural byproduct
of the farms meat stock. This was used to feed the algae which is the
natural food of this species of fish. As the algae became established
meatmeal was discontinued. At different times other feedstuffs were
used according to what needed to be recycled and fitted into the
nutrition needs of the fish farm. For instance feather meal was used
at one stage, milk powder at another. Nothing is being put in at this
Over time other associated water species have found their way
into the ponds and live harmoniously in this ecosystem. Nets cover the
ponds to protect against bird predators, and plants natural to the
site have been re-established. Tests showed the water at the outlet
into the harbour to be purer than that actually in the harbour - the
Kaipara Harbour is the second largest natural harbour in the world and
certainly one of the cleanest.
When fish populations begin to increase too fast stock is returned to
the harbour through the outlet system.
I am not a technically minded person and some of this detail may be a
little inaccurate but the concepts are pretty much what it is all
about. The over-riding motivation in setting this up was to show that
quality protein could be grown sustainably in harmony with the
existing eco-system and in fact could assist it, which it does through
water purity, providing breeding areas and restocking the harbour. The
model has aroused interest in local Maori groups whose traditional
protein staple was fish. It has also been studied by students wishing
to help solve problems in third world and developing nations where our
traditional beef/sheep etc are not appropriate suppliers of protein.
I should add that the fish farm is part of a 1,000+ acre farm
running beef and dairy cattle, plus sheep, tree crops, timber etc and
a number of other 'diversified' operations.
It is a commercial scale operation and proves I think that choosing
the sustainable species (pl) for your locale, relating that to what
'wastes' are available locally in terms of inputs needed means that
aqualculture, even 'intensive' saltwater aqualculture is a
I believe there are also models in permaculture concepts which
involve a tiered system of raising small livestock, e.g. poultry, with
fishponds beneath which are 'fed' by the waste from above. While this
obviously lends itself to small scale operations it could surely be
adapted to commercial scale salmon etc farming.