** 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. _______________________________________________ Sarnissa-african-aquaculture mailing listSarnissa-african-aquaculture@lists.stir.ac.ukhttp://lists.stir.ac.uk/cgi-bin/mailman/listinfo/sarnissa-african-aquaculture<http://lists.stir.ac.uk/cgi-bin/mailman/listinfo/sarnissa-african-aquaculture> ------------------------------ _______________________________________________ Sarnissa-african-aquaculture mailing listSarnissa-african-aquaculture@lists.stir.ac.ukhttp://lists.stir.ac.uk/cgi-bin/mailman/listinfo/sarnissa-african-aquaculture<http://lists.stir.ac.uk/cgi-bin/mailman/listinfo/sarnissa-african-aquaculture> _______________________________________________ Sarnissa-african-aquaculture mailing list Sarnissa-african-aquaculture@lists.stir.ac.uk<mailto:Sarnissa-african-aquaculture@lists.stir.ac.uk> http://lists.stir.ac.uk/cgi-bin/mailman/listinfo/sarnissa-african-aquacultu…