Age and growth of the daggernose shark, Isogomphodon oxyrhynchus, from northern Brazil

Age and growth of the daggernose shark, Isogomphodon oxyrhynchus, from nort hern Brazil were determined from 105 vertebral sections stained with alizar in red-S representing 46 males, 52 females and 7 specimens of unknown sex ( 58.4 to 141 cm-TL) and verified with length-frequency analysis of 1135 spec imens (632 females and 503 males, 58-160 cm). Marginal increments did not s how significant differences throughout the year, and it was assumed that on e band is formed annually. Different tests provided varying results for gro wth curve comparisons between sexes; the curves were similar, despite biolo gical differences. von Bertalanffy growth parameters estimated from back-ca lculated mean lengths, observed mean lengths-at-age and length-frequency an alysis were of the same magnitude. Parameters generated from observed lengt h-at-age were chosen for describing growth for the species: L-infinity 171. 4 cm, k 0.12 year(-1) and t(0)-2.612 years. The largest female aged from ve rtebrae was 12 years old, whereas the largest male was aged at 7 years. Neo nates, similar to 42.3 cm, showed one band in the vertebrae, formed at birt h, or soon thereafter. Males are mature at 103 cm or 5-6 years and females at 115 cm or 6-7 years.