13 Mar
2012
13 Mar
'12
6:47 p.m.
From: Kenneth Betts [mailto:kwbetts2@gmail.com]
Sent: 13 March 2012 14:48
To: William Leschen
Subject: Re: [Sarnissa] Dear members,
Here are some pictures of the hand held graders that I made. Sorry the first pictures
were too large.
Ken
On Mon, Mar 12, 2012 at 1:33 AM, William Leschen
<william.leschen@stir.ac.uk<mailto:william.leschen@stir.ac.uk>> wrote:
Thanks Kenneth
But please could you send smaller photos - file size max 500kb - 2M each is too much
for the forum - then please resend your message
I hope someone also sends in some photos of normal bar graders - these work well and
easy to pivot up and down so operator doesn't have to lift whole weight of fish each
time
Best wishes Will
From: Kenneth Betts [mailto:kwbetts2@gmail.com<mailto:kwbetts2@gmail.com>]
Sent: 11 March 2012 14:18
To: sarnissa-african-aquaculture Mailing List
Subject: Re: [Sarnissa] Dear members,
Here are some pictures of the hand held graders that I use.
Kenneth
On Sat, Mar 10, 2012 at 12:53 PM, Nazael Madalla
<nmadalla@googlemail.com<mailto:nmadalla@googlemail.com>> wrote:
Dear Kenneth,
Your homemade graders sound interesting. Can you please attach a photo.
Cheers!
Nazael.
On 10/03/2012, Kenneth Betts <kwbetts2@gmail.com<mailto:kwbetts2@gmail.com>>
wrote:
For my farm, which is only small, I made hand held
graders out of blue
plastic barrels. I cut each 80 liter barrel in half to make two "baskets".
I cut hand holds in them. I a local tooling shop to make a set of iron
hoops of graded sizes (20 mm, 25 mm, 32 mm etc) which I heat in a fire and
then melt lots of holes in the bottom and sides of the baskets, each basket
with the same size hole. Three people working with these baskets can sort
thousands of fish very accurately in a few hours.
On Fri, Mar 9, 2012 at 11:19 AM, Patrick Wood
<patrickjwood@yahoo.com<mailto:patrickjwood@yahoo.com>>wrote:
--
_________________________
Nazael Madalla, PhD
Lecturer (Aquaculture)
Department of Animal Science and Production
Sokoine University of Agriculture
P.O.Box 3004
Morogoro
Tanzania
Mobile:+255 769 220 212<tel:%2B255%20769%20220%20212> or +255 719 489
171<tel:%2B255%20719%20489%20171>
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The Sunday Times Scottish University of the Year 2009/2010
The University of Stirling is a charity registered in Scotland,
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**
How about using people to hand grade? Is there not a prescribed hand
method and accompanying research on labour/size fish/grade rate?
Karen L. Veverica wrote:
Ernest, I made a grader locally (in Ghana) but had to leave it at a farm
and they decided they did not wish to try it; it is still there. It is
supposed to be handed over to another vary large farm for trial but I
doubt
this has happened.
Graders can be expensive if you want them to work well; they can be
home-made but often are not made well-enough to be consistent.
Also.... even if you have a good grader, if it is used wrongly, it will
not grade. The density of the fish in the grader is important; if too
few,
the fish do not wish to swim out; if too many, the fish can't get out. If
you create a water current to encourage them to go out, they may end up
jumping out. For grading tilapia fry, I like to have a grader with good
enough freeboard (about 30 cm) so the fish do not jump out without having
to put a cover on.
To better assist the others who will no doubt wish to respond, please give
the numbers of fish you are wishing to grade at a time and their size. You
mean tilapia, right?- these are best graded through the sides of a grader;
for catfish, graders should have the bars on bottom. Most graders have
bars
on 2 sides and bottom but people making home-made graders should know what
is most important for their fish.
Grading is rather important when it comes to getting better feed
conversions and when it comes to trying to get fish large enough so they
do
not swim out the mesh of your cage.
We use the floating "basket graders" if we have fewer than 10,000 fish to
grade. When we have a lot, we use a bar grader/crowder in a large tank.
You have to give the fish time to grade.
After you tell us the fish size you wish to grade,I am sure several of us
can send you photos.
Karen L. Veverica
Department of Fisheries and Allied Aquacultures
International Center for Aquaculture and Aquatic Environments
Auburn University, Alabama, USA
office: +1-334-844-4667<tel:%2B1-334-844-4667>
cell: +1-334-332-1560<tel:%2B1-334-332-1560>http://www.ag.auburn.edu/fish/
On 3/8/2012 12:08 PM, Ernest Abiew wrote:
Could any member help me with this information. I wanted an information
on a simple and a practical method or methods of grading fish that can
easily be used by farmers in Ghana.
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