Age and growth of the zebra shark Stegostoma tigrinum (Forster 1781), at Loro Parque Aquarium

Abstract

Breeding programmes have been developed at the Loro Parque Aquarium for the past eight years focusing mainly on zebra sharks Stegostoma tigrinum. These programmes provide the possibility to study the growth of specimens and the relation between age, length and weight. Data obtained from a total of 288 biometric measurements from 24 (12:12:0) specimens were analysed, of which 18 (9:9:0) were born at Loro Parque. At the time of birth (t₀) the average total length (TL) of the new-borns was 26.5 cm and the average total weight (TW) was 71.94 g. The von Bertalanffy growth function (vBGF)obtained, where y=186.78×[1-e^{-0.56×(x-0.27)}], shows accelerated growth (k=0.56) within the first 3.5 years (1200 days) of life. No significant difference was found between growth of males and females. To study the length-weight relationship, a regression analysis was performed with TW=2.16×10^-4×TL^3.54 presenting a positive allometric relationship and R²=0.9857, which demonstrates strong correlation between the variables.