Vertebral Growth Zone Deposition in Pacific Angel Sharks

Vertebrae and body size measurements were taken from 334 Pacific angel sharks collected from commercial gill netters off Santa Barbara, California, from Sept. 1979-Nov. 1983. Radiographs of vertebral centra from 247 specimens were studied to delineate calcified bands for age determination. The vertebrae of the smallest newborn sharks (260 mm TL) had 6 or 7 bands while those of the largest (1140 mm TL) had 42 bands. Bands were not deposited annually but were related to somatic growth. This hypothesis is supported by the number of bands in embryos and newborn Pacific angel sharks, growth of girth, and vertebral centrum dimensions, laboratory grow-out studies of tetracycline-injected sharks, and evidence from six tetracycline-injected tag returns.