If one treatment always feeds first, then the other treatment may get hyped up waiting for you to stop timing the flurry of activity in the other cage. The treatment that eats last may be ramped up and in a more competitive state waiting its turn.
Well...you found one of my training secrets there. Discovered by accident actually. Very good point, and it DOES matter.
If my PVC pipe brackets work as planned, both will be fed at the same time to eliminate this because I tried to train SMB and YP in one of these cages with a divider and one day I noticed after throwing feed to the SMB, the YP were hitting the surface but there was no feed there. It was 10-12 days into it when this happened so I did finish by alternating the feeding. The SMB would occasionally hit the surface but only seldom, the YP went nuts though.
Interesting experience you have noted. I am glad this became part of the conversation.
The other thing about feeding the fish, is that if they are removed from the cage. weighed and measured, and returned, then they most likely will not resume feeding right away. Any stressors on the fish will suppress the feeding, and potentially skew the test.
I agree with this. There is nothing wrong with waiting until the end to get weights and lengths or doing the measurements on 30 day intervals or some other broader interval than 1 week. This is an advantage of using a feed schedule that anticipates growth with previously modeled factors or is guided by feed consumption times.
As much as one would like to maximize growth, because we are comparing feeds, this should not be the priority. If we treat feeding rates equally using equivalent samples of fish then we will arrive at a more genuine understanding of comparative nutrition.
Because the control will not be equivalently caged, we will not get an accurate picture of absolute nutrition received. If we try to attribute all of the gain to feed we may well be giving credit that belongs to pond food organisms to the feeds. We should reserve that there is uncertainty as to whether the separate cages have the same opportunities for natural foods ... unfortunately two cages cannot occupy the same real estate at the same time.
