Dillon Nichols wrote:I know nothing about any of these fish, or Peru, and not that much about aquaponics...
That feed cost is insane by my standards. My experience is with hog and chicken feed. This stuff is expensive here, compared to more agricultural parts of Canada not located on an island far from grain country, and VERY expensive compared to the USA.
And yet a metric ton of feed costs me, a small farmer with zero bargaining power, around $670. 67 cents a kilogram, Canadian dollars, around 48 cents USD.
It seems clear that anyone selling those fish for the price you describe is either using a much more economical feed, or is being heavily subsidized in some way. Or, they are not selling at that price; I wonder what that fish is worth somewhere else?
In my region, successful fish farms are generally biggish. There is a lot of economy of scale to be leveraged. Aquaponics on a modest scale may have more profit potential from the produce side.. at least, that would be my guess for my region. In that case, a slow growing but cheap to feed fish might make sense despite the lower market value.
Bryant RedHawk wrote:
Steve Mendez wrote:I have done a bit of research on commercial eel culture. Yes, there are profitable eel farms. They are a much sought after food item in several countries.
I haven't found any instance where they are spawned in captivity. Somebody may be doing it and they are keeping quiet about it. I wouldn't blame them, elvers or glass eels or baby eels are one of the most high dollar aquatic animals there are.
Eels are a catadromous species meaning that they migrate down rivers to spawn in the sea, as opposed to anadromous species that migrate from the sea up the rivers to spawn (salmon). Anadromous fish are routinely spawned by people for commercial purposes, catadromous species not so much.
This means that baby eels must be captured as they migrate up the rivers and then sold to eel farmers for grow-out. Some states have a glass eel season. They are tiny and see through, thus glass eels.
I have no problem with this practice as long as their capture is controlled and regulated by qualified Biologists.
I recently heard that there is a small consortium of eel men in Northern Japan that are trying to build a method of spawning eels.
Now whether or not it comes to pass is another story, but they apparently have two marine biologist working with them so we can hope that this happens, that would take pressure off the wild eels.
(On the other hand, if they fail and give up (very unlikely) that might be something to start working on here in the states then sell the technology and equipment to Japan and other countries)
Tereza Okava wrote:I used to translate a lot of research in the area of fish farming, most about what could be added to fish chow in order to produce better results more cheaply (off the top of my head I can think of studies on using orange peels, crab shells, and grain mill waste over the past year or three), which indicates you're not the only one wondering how costs can be cut.
The studies didn't specifically address Arapaima (they're also in my region, here we call them pirarucu) but if I recall they are fast growers and get BIG, and i imagine they do have very specific nutritional needs because they grow so large and so fast. I imagine you've already seen it in your research, but the FAO has a nice factsheet about farming pirarucu, and a major stumbling block for farming these fish is reproduction. If you haven't read it yet, you might find this interesting. http://www.fao.org/fishery/culturedspecies/Arapaima_gigas/en
Bryant RedHawk wrote:Biology and Ecology of Anguillid Eels (This is the latest authoritative book on this subject)
Available at the CRC Press https://www.crcpress.com/Biology-and-Ecology-of-Anguillid-Eels/Arai/p/book/9781482255157 Hard back is available for 190.00, E-book is also available 52.16
While the hardback seems like a steep price, do remember that scientific books are full of full color photos and you likely won't have access to that information elsewhere. Plus today you have alternatives like the e-book and renting an e-book.
I far and away prefer to buy hardbacks for my reference library, but that is just me, and I do tend to use my library a lot.
Joe Kern wrote:Aloha, good suggestions from everyone. One thing to consider, though is that these grasses may not be temperate-level aggressive, but tropical-level aggressive, meaning can eat you or your house and car, or at least smother your trees in a few days. It is really a different situation if you do not have experience with the crazy tropical grasses, planting trees or even just working with the land can be near impossible with certain species. Perhaps Windy can provide the species so we can get a better idea of what they are dealing with, and location information, too. The really aggressive tropical grasses can form monocultures that can resist grazing, tillage, even moving through them to an unbelievable degree. They are not like temperate grasslands that, if left alone, will become forests relatively quickly, but can maintain themselves as grassland for (in human terms)nearly forever. This was talked about a bit in the early Permaculture texts, probably because in parts of Australia the early designers were dealing with some of the really difficult grasses. This is one reason why temperate-style ranching has been so devastating for tropical forests, because when forest is cleared for pasture, if it is later abandoned, it does not quickly and easily revert back to woodland, but requires active intervention to get out of the grass cycle. Extremely overgrazed areas are actually easier to deal with in some ways, because the aggressive grasses are usually gone by then. There is a difference between knee or waist high tropical grass and the 15ʻ+ tall grass monoculture with 1-2" thick stems, saw-bladed leaves and itchy hairs that we very often deal with in Hawaiʻi. I am only bringing this up to say that it may not be as simple as planting trees and watching them grow, because I deal with the opposite all the time. The grasses we deal with almost always need to be cleared mechanically first, whether with hand tools up to large equipment. Not that I would recommend them, but herbicides are generally not effective unless sprayed from the air, or along the edges over a long period of time, just because no one can walk through them to spray.
One thing I have learned is that if you do any kind of clearing, you must have a plan to occupy all of the cleared space with desirable plants immediately, and maintain your cleared area somehow until they get established, or you will lose your cleared ground and your plants very quickly.
Many of the grasses are rhizomatous, and can propagate themselves from small pieces of stem, so it is not just above ground but below that you need to consider. A big tractor with a flail mower is a great tool to cut lanes in the grass, many people opt for a bull dozer here too, and it is not a bad idea with some grasses. If you can clear wide lanes that you can mow or maintain somehow, you can start a nucleus of desirable vegetation that can cope with the grass, but I would not say that it is something you can plant and walk away from. Any kind of tillage is usually impossible with the grasses I deal with regularly, because they sprout from the stems and are usually too big, tough and woody for anything I know to deal with. After the grass is mulched (2-3 passes with a flail mower) and broken down, some tillage is possible, but that has its own problems in the tropics, usually resulting in lost fertility. By the time the grass breaks down enough to till in, the rest has usually grown back too tall to deal with anyway. I find it works to figure out your guild or companions that will go with each tree and plant everything at once. Perrenial peanut is a good low cover for right around a tree, and pigeon pea and crotalaria species further out. Comfrey grows in the tropics, and it and vetiver can work for a barrier to rhizomes if planted thickly. Plant everything extra thick and cut any extra down later for mulch if it is in the way of your desired tree. If you can fill a 10ʻ circle around your tree with good plants and keep the aggressive grasses out, your trees have a fighting shot at surviving. We also use the kukui tree Aleurites moluccana to take up space when needed. If that is available where you are, it grows fast, provides useful products and lots of mulch, breaks down fast and is easy to cut down and replace with more desirable trees, although it is also desirable in its own right.
Cattle can deal with some of the worst grasses, and goats can eat the stems, but with really tall, thick grass, intensive grazing is difficult. Equipment can make lanes in the grass for access and fencing, to make it easier, but this would not be a quick way to establish a forest. Most people seem to opt for extensive grazing over a very long time, after which the fertility is largely gone anyway and the land will be overgrazed, plus in that kind of management cattle and goats would surely find any trees and eat them too.
I have attached a couple pictures of what I deal with that may give some idea of what grass in the tropics can look like, they are not the most illustrative, but are what I have available right now.
You have your work cut out for you if you opt for a parcel of that size, even a few acres of the really aggressive grasses can be hard work to establish trees in!
I think this lengthy reply may help some that do not have as much experience with tropical landscapes understand how it is different from temperate, and how much more challenging it can be. The title of the post is worth a book or two in and of itself, as well as a lifetime of work for many of us. I think it is worth a lot of discussion, not just for the original poster, but for the entire world at large, based on the impact it could have on the worlds ecosystem.
Borislav Iliev wrote:Dont kill them, just cut them low, plant your trees next to them, and every time the old trees try to grow just cut them low again and use that growth to mulch around your trees, if your trees are fine enough they will make a good shade and will suppress the growth of these old trees eventually, or plant some bushes to even further shade them. As long as the old trees are low but still growing then you can use that as an indicator how well you are utilizing sun energy, the moment they give up because of the shading, then you will know you have done it right, till then use them to improve your soil.(this may not be the right way for you though, if you dont have time for that)