Table 5 Arguments raised against the GOLT: Different definitions of anabolism and catabolism.

NoArgumentsRefutations
5.1Von Bertalanffy’s hypothesis of a surface-limiting fish
growth (which is a key element of the GOLT) is wrong
because the absorptive surface area of the gut is not in
permanent contact with food (162, 163).
Von Bertalanffy (1924) did not commit himself to stating
that the surface-limiting growth was that of the gut. He
thought that “the actual surface responsible for growth
of an organism is in general unknown” (20). However, he
clearly favored a link to respiration (albeit without
explicitly mentioning gill surface area).
5.2The claim was also made that “apparently, it was overlooked
that although catabolic processes are going on all over
the body, the necessary oxygen supply has to be
introduced through some surface or the other, mainly
the gills. With our basic assumption of isometric growth,
this 2/3 means that catabolism is proportional to w2/3
(82).
This was not overlooked. In the GOLT, the catabolic
processes “going on all over the body” do not require
oxygen. They consist of the (temperature dependent)
spontaneous denaturation (equal to loss of the
quaternary structure) of protein molecules. This process
is proportional to weight; the denatured proteins must
be resynthesized, which requires ATP and hence O2.
However, this is part of anabolism, not catabolism.
5.3Another claim (164) was “…anabolism is proportional to the
area of the circulatory network rather than to gill surface
area (35).”
If this were correct, then the scaling factor of anabolism to
weight in fish and invertebrates would always be 0.75.
This, however, is emphatically not the case (15, 16, 165).
5.4A critique (166) of (7) included “Methodological
shortcomings include (i) assimilated consumption (the
‘anabolic’ part of the growth equation) is assumed to be
proportional to oxygen, but oxygen is only a limiting
factor for growth not a controlling factor, i.e. it only affect
growth if the oxygen concentration is below a critical
value (167).”
The response (7) was that “[w]hile Brander et al. cite Brett
(167) to suggest that oxygen is a limiting factor for
growth, and not a controlling factor, there is abundant
theoretical and empirical support in the peer- reviewed
literature for oxygen being both a limiting and
controlling factor for the growth of fish and aquatic
invertebrates.” (14, 93, 168172).