An individual-based length back-calculation method was developed for juvenile Baltic sprat (Sprattus sprattus), accounting for ontogenetic changes in the relationship between fish length and otolith length. In sprat, metamorphosis from larvae to juveniles is characterized by the coincidence of low length growth, strong growth in body height, and maximal otolith growth. Consequently, the method identifies a point of metamorphosis for an individual as the otolith radius at maximum increment widths. By incorporating this information in our back-calculation method, estimated length growth for the early larval stage was more than 60% higher compared with the result of the biological intercept model. After minimal length growth during metamorphosis, we found the highest increase in length during the early juvenile stage. We thus located the strongest growth potential in the early juvenile stage, which is supposed to be critical in determining recruitment strength in Baltic sprat.
Canadian Journal of Fisheries and Aquatic Sciences, 2012, Vol 69, Issue 7, p. 1214-1229
cellular growth; metamorphosis; ontogenetic change; Pisces Vertebrata Chordata Animalia (Animals, Chordates, Fish, Nonhuman Vertebrates, Vertebrates) - Osteichthyes  Sprattus sprattus species Baltic sprat common larva, immature; 04500, Mathematical biology and statistical methods; 10515, Biophysics - Biocybernetics; 20004, Sense organs - Physiology and biochemistry; 25502, Development and Embryology - General and descriptive; Computational Biology; Sensory Reception; otolith sensory system; back-calculation model mathematical and computer techniques; biological intercept model mathematical and computer techniques; Development; Models and Simulations; Sense Organs