I disagree. The system is not that cut and dry. Assume 1 grass carp gains 3 lbs in a single year. Your explanation would lead us to believe that the carp ate no more than the equivalent of 3 lbs dry weight vegetation to gain that 3 lbs. What happens to the dry weight of vegetation that has to sustain metabolism, immune system function, and to provide basic energy needs? That dry weight is burnt as fuel and not released back into the system. I don't know the numbers, but am positive that actual weight gain can only comprise a fraction of total dry weight eaten, even in consideration of dry weight not digested by fish. Assuming filamentous algae did not develop with grass carp present, even undigested plant material that degrades to nutrients and is reassimilated into vegetation and can be processed by grass carp again.
