Idade e crescimento do tubarão lombo- preto, Carcharhinus falciformis , capturado no Atlântico sudoeste tropical

Abstract

From October 2007 to March 2011, 105 silky sharks, Carcharhinus falciformis (Muller e Henle, 1839), (68–274.2 cm in total length, TL) were collected from industrial fleet (longline) carried out on Southwestern Tropical Atlantic (010º W/ 035º W, 05º N/ 30º S). Vertebral sections from 34 males (105–268.2 cm TL), 35 females (85–274.2 cm TL), and 36 individuals of unknown sex (68.8-256.1 cm TL) were analyzed. One 68.8 cm TL individual did not have birth ring. The index of average percentage of error (IAPE) estimated from two readings ranged from 0 to 7.69 (mean=3.88%) in the vertebrae of specimens with 1 and 14 band pairs, respectively. There were no differences (p 0.05) in the monthly marginal increment (MIR) analysis between months then we considered an annual ring deposition as other species of the Carcharhinidae family, including Carcharhinus falciformis. Ages range from 0 to 20 years. There were no differences (p 0.05) in growth between sexes. Models derived from von Bertalanffy, particularly the VBGM two phase, best represented growth for the species, which was evidenced by the lowest Akaike information criterion value. Growth parameters estimated for both sexes were L = 303 cm, k = 0.086, t0= -4.71, h=0.17, and th=11.62 with the VBGM two phase model, and L = 292 cm, k = 0.089, and t0= -4.87 with the VBGM. The VBGM was used to other analysis. Males and females mature at 10.8 and 12.5 years of age, repectively, and the age that attain 95% of the L is 30.3 years.