Really the question is debatable. But Sir, since long we are using the same measure to calculate FCR and the term becomes so popular that, it is inevitable to get rid of theses terminology. Most of the time we exaggerate our findings and we assume that weight gain by the fish is only due to the feed we supply to feed the fish.But such contemporary term should be replaced and stalwarts like you in the field of Fisheries and aquaculture can come up with some recommendation.

 Dr Amit Ranjan,

Thank you for your flattering answer - as you have said the term has been in usage for long and it might have advantages, especially for the fish farmers. 

Sir,  thank you for your response. I still remember when my mentor Dr.  Nandeesha Sir introduced me to you during Asian Pacific Aquaculture,  2011 conference at Kochi,  Kerala. Sir,  how are you and how is your health. I always see your updates and question you ask in the research gate and i must praise you for this as i am getting really nice information and update about aquaculture sector in present and past.  I seek your continued blessing to my future endeavour. 

I appreciate hearing from you reminding us of our good friend late Dr Nandeesha. Good to know of your work too. I raised some questions specifically to increase the awareness of the principles of aquaculture,  With best wishes for the success of your work and best regards.

Thank you very much Sir for your response. 

The main problem or imperfection is the assumption that one can accurately measure feed intake by animals being fish, poultry, pigs etc. What you generally do, is measure the amount of feed disappeared of the feeding trough.

Thus there is always an insecurity in this value, depending mostly on the design of the feeding bin and the behaviour of the animals (playing with feed etc)

Sir, I fully agree with the Dr. CA Kan - it is the difficulty in measuring feed intake accurately that we are not sure about feed conversion. First of all, I think the term should be Feed Conversion Ratio; naturally available food (say in pond system) intake by fish is not considered in FCR. The question was not so clear to me - whether you are suggesting to change the terminology or asking about ways and means to improve feed conversion by fish. If terminology is the question, then we have many other measurements that we can use - say feed efficiency ratio, protein efficiency ratio, productive protein value etc etc. In case of the latter, feed formulation can be taken care of including supplementation of a variety of additives in the feed, feeding methods, feeding strategies etc.

Thanks, Dipesh. I was referring t imperfection in terminology.

Thank you Sir. Please share your views on the subject...

Dipesh, I am not suggesting any change in terminology, as long we recognize what the abbreviation is about. Why make a change for a term accepted and used for so long - besides the term is used especially by the farmers - it is better that we do not confuse them further.  I agree with you that the conversion concerns feed rather than about food, but they come quite close. The spelling out could well be that as you suggest. Surely there is some imperfection that often there is some unaccounted feed going into the the food in the FCR calculation, as indicated by Dr. Kan.. 

What I was impressing on is that even if we accept the FCR as it is, there is need to realize that there is some incongruity in the two basic units of feed and weight gain in fish - we do not take into account the level of hydration in the two entities used in deriving FCR. The water content in the feed (food) and the mass increase in fish can vary very widely - while the feed pellets may be nearly dry the the fish meat is about 75% water. Ideally we could have both units in dry form - feed and fish meat in dry weight, as nutritionists could expect to be. But again this would be a problem for the common fish farmers. I am only suggesting that there must be clear understanding of the terms used among scientists and aquaculture advisers.

Thank you very much for the explanation Sir and I fully agree with your views. We will be more accurate if we convert both feed and fish weight as dry weights.

Dipesh, good to see your response. Perhaps we could do better if we convert to energy content in both.

Another expression is Food Conversion Efficiency (FCE) which is  calculated by dividing the  weight gained by fish by weight of food consumed in a finite time multiplied by 100. It is usually expressed as %.

Thanks, Sahadevan.

 Yes, that term is correct reflects the apparent food conversion rate. can be improved by calculating the real conversion rate by amount of energy lost through waste and put it up from the food consumed and calculated weighted increase achieved relative to the amount of food metabolism