i have been meaning to make this thread for a while now, but life kept getting in the way. anyway, i finally managed to take pictures of the whole process, so now i can share, in detail, how i harvest live blackworms from my pond. i imagine you could do this in just about any fishless pond that is surrounded by mud and covered in duckweed. apparently, blackworms live almost everywhere.
anyway, first step is to collect duckweed. the worms crawl out of the mud surrounding the pond and into the duckweed, presumably to feed on the dead duckweed that gets stuck in the floating mats. here is what it looks like at our place: http://imgur.com/gallery/jbGTNm3
all of the duckweed has blackworms in it, but not all in the same concentrations. i typically find more around the edges, so thats what ill usually scoop up first:
ill usually check what i scooped up to make sure im not wasting my time with it. if i see a few blackworms wriggling around, ill usually keep it. in this pic, you can see a couple mature adult worms right away: http://imgur.com/gallery/GPCNXQB
its a good idea to always check your net before you dump the duckweed into the bucket... sometimes stragglers like to hitch a ride: http://imgur.com/gallery/LOrlJs7
even if the duckweed does not have a lot of visible worms, it usually still has some worms in it. if i were spending all day collecting worms, i wouldnt toss any of it out. but, i only had a couple hours to do everthing and take pictures. if a clump of duckweed looks like it has no worms, you can still set it aside and wait a day. the worms that are present will go straight down. if you do this on a tarp, it would be easy to go back the next day and collect the worms from underneath all the duckweed. my daughter found this old clump of duckweed and inspected it: http://imgur.com/gallery/MbSGBhQ
underneath the duckweed, she found a bunch of worms: http://imgur.com/gallery/k7Nrt2C
when we feel like we have enough duckweed to get a decent amount of worms, we bring it up to the house and use a tall feed bin to separate the live duckweed, which floats, from detritus and worms, which sink. we are currently using a feed bin, but a large trash can or 50 gallon drum would work just fine too. all we do is swirl the duckweed around in the water to shake loose anything that will sink: http://imgur.com/gallery/ciDTIFc
once we have scattered a bunch of duckweed beneath the water, we wait about 30-45 seconds for the live duckweed to float up and for everything else to sink to the bottom: http://imgur.com/gallery/mbNZd82
if we work too fast, we wont give the worms time to fall away from the duckweed. because we only have one bin at the moment, we inspect the cleaned duckweed for worms before we remove it from the bin. after i get a couple more, i probably wont have to do this, ill just be mixing up duckweed in one bin while the others are settling: http://imgur.com/gallery/A85P0X8
the cleaned duckweed goes into a container and will get fed to koi, returned to the pond, or put out in our garden: http://imgur.com/gallery/w5eJjUk
after we have gone through and cleaned all of the duckweed in the bucket, we let it set for about 15 minutes and then pour off the water: http://imgur.com/gallery/aGXMQGi
at this point, its important to pay attention to make sure you dont pour out the mulm. the gunk at the bottom contains all the blackworms: http://imgur.com/gallery/6roJpmg
all the sludge at the bottom gets poured back into the bucket and brought inside: http://imgur.com/gallery/sjGhkDo
for the next step, we pour all the sludge into a small aquarium fish net in order to condense it. condensing it makes it easier to handle for the next step: http://imgur.com/gallery/Cx8H8j3
we lay a net, or any kind of mesh really, across a filled aquarium. we take a small ball of the sludge and spread it over the surface. we then take a power cord, running off of an adapter so the voltage is low, and zap the worms with exposed wire. the electricity is low enough that i cannot feel any voltage when i am holding both wires, but its enough to evoke a response in the worms. dont let the wires tough though. even though it isnt enough to shock you, it will still spark if the wires touch: http://imgur.com/gallery/RmrjSUA
the worms will scatter, leaving most of the detritus in the net/mesh: http://imgur.com/gallery/U3OSTWm
we basically repeat the last step until we have gone through all the sludge. we dont throw the sludge away at this point though. it still has a bunch of worms in it, so we put the spent sludge in a bucket to let the worms remaining worms rest and then run them through one more time. we will then take all the worms we collected and run them through a smaller mesh, using the same voltage method. after going through just two buckets of duckweed, this is the result: http://imgur.com/gallery/E7811lz
i dont know exactly how many blackworms that is, but its more than enough to feed all of our fish for quite a while. it also keeps my daughters salamander larvae fat and happy: http://imgur.com/gallery/Cjla6m9
anyway, thats pretty much the whole process. if i were to get a few more bins and set up actual stations, i could probably produce about five times as many worms in the same amount of time. the process takes about an hour when all said and done, but over half of that time is spent waiting for stuff to settle out. right now, its easy to get a pound or two of blackworms every evening. i hope to refine the process well enough to produce about five pounds a day in the summer. im hoping that when my daughter gets old enough to start wanting money, she will harvest and sell some of them. in the mean time, i will be looking into ways to increase the ponds production. right now, the only thing that is feeding all those black worms is decaying duckweed. i imagine tossing some kind of high protein feed out there might increase their numbers a bit.
so, there you have it. if you happen to find a fishless pond with lots of duckweed, check it out. you might just have a free source of black worms.