Young tiger sharks apparently grow rapidly off northeastern Brazil. A new study predicts a total length of around 1.65 metres at one year and about two metres at a year and a half. These are model estimates, not directly observed life histories.
The study includes 221 animals measuring between 82 and 426 centimetres. Growth bands in the vertebrae were examined for 67 individuals. However, regular annual band formation could not be confirmed; the model assumes it. The resulting age estimates therefore remain uncertain.
Coastal waters for the youngest animals
Coastal samples from Brazil were dominated by newborn and very young tiger sharks, while oceanic samples consisted mainly of juveniles. This is consistent with age-related habitat use, but does not demonstrate individual migrations.
Maturity as a regional estimate
Using a previously published maturity length of 3.10 metres, the growth model estimates about 4.7 years to sexual maturity. Maturity was not directly observed. This figure is therefore not a worldwide age threshold for tiger sharks. The findings add to our knowledge of the region studied; they do not establish a new maximum lifespan.
