
TY  - JOUR
A1  - Lessa, Rosangela 
A1  - Santana, Francisco Marcante 
T1  - Age determination and growth of the smalltail shark, <emph type="2">Carcharhinus porosus</emph>, from northern Brazil
JF  - Marine and Freshwater Research
JO  - Mar. Freshwater Res.
Y1  - 1999
VL  - 49
IS  - 7
SP  - 705
EP  - 711
KW  - 
UR  - https://doi.org/10.1071/MF98019 
N2  - Age and growth of C. porosus was estimated from seasonally formed marks in vertebrae of 504 specimens (30.0&#8211;101.0 cm total length), and from length&#8211;frequency data from 1128 individuals (29.4&#8211;120.5 cm). Estimated von Bertalanffy growth parameters were: from observed length-at-age, L&infin; 125.1 cm, K 0.101 year-1 and t0 &#8211;2.89 year; from back-calculated lengths, L&infin; 136.4 cm, K 0.077 year-1, t0 &#8211;3.27 year; and from length&#8211;frequency analysis, L&infin; 131.0, K 0.080 and t0 &#8211;3.40. Growth did not differ significantly between sexes. Males and females were mature at 71.0 and 70.0 cm, respectively, corresponding to 6 years old. The largest shark aged from vertebrae was a 12-year-old female (101.0 cm). Growth rates calculated from mean observed lengths were 7.0 cm year-1 for the first four years and 4.0 cm year-1 after maturity. Lee&#8217;s phenomenon was not apparent. The annulus forms from September to January. Parameters derived from back-calculated lengths were considered to best describe growth. Like most carcharhinids, C. porosus follows the general pattern of K-selected species, exhibiting slow growth, late maturity and low fecundity. Resumo. A idade e o crescimento de C. porosus foram estimados a partir de marcas sazonais em v&#233;rtebras de 504 indiv&#237;duos (30.0&#8211;101.0 cm comprimento total) e atrav&#233;s de distribui&ccedil;&#227;o de freq&#220;&ecirc;ncias de comprimentos de 1128 indiv&#237;duos (29.4&#8211;120.5 cm). Os par&acirc;metros de von Bertalanffy obtidos com comprimentos observados na captura foram: L&infin; 125.1 cm, K 0.101 ano &#8211;1 e t0 &#8211;2.89 anos; com comprimentos retrocalculados: L&infin; 136.4 cm, K 0.077 ano-1, t0 &#8211;3.27 anos, e da distribui&ccedil;&#227;o de freq&#220;&ecirc;ncias de comprimentos obteve-se: L&infin; 131.0 cm, K 0.080 ano-1 e t0 &#8211;3.40. O crescimento n&#227;o difere entre sexos. Machos e f&ecirc;meas s&#227;o maduras com 71 e 70 cm, respectivamente, correspondendo a idade de 6 anos. O maior esp&#233;cime cuja idade foi estimada das v&#233;rtebras tinha 12 anos (101.0 cm). As taxas de crescimento calculadas dos comprimentos m&#233;dios observados foram 7.0 cm ano-1 para os primeiros quatro anos e 4.0 cm ano-1 ap&oacute;s a maturidade. O fen&#244;meno de Lee n&#227;o ocorreu. O anel se forma entre setembro e janeiro. Os par&acirc;metros obtidos do retroclculo descreveram melhor o crescimento. Como muitos carcharhinideos, C. porosus segue o padr&#227;o das esp&#233;cies da sele&ccedil;&#227;o K, exibindo crescimento lento, maturidade tardia e baixa fecundidade. 
ER  -

