The importance of juveniles in modelling growth: butterflyfish at Lizard Island

I established and fitted von Bertalanffy growth functions to size-at-age data for four species of chaetodontids at Lizard Island. Special emphasis on juveniles provided detailed information of the early growth period. All four species demonstrated rapid initial growth achieving an average of 92% of maximum theoretical size in the first 2 years. I used various constraints of the theoretical age at length zero (t(0)) in an analysis of both complete data sets and data sets using only adult fish. An unconstrained value of t(0) resulted in the best-fit (maximum r(2)) curve when juveniles were included. When excluding juveniles, it was necessary to constrain t(0) to an approximate settling size to most closely represent the growth of the species.