Kotas J E, Mastrochirico V, Petrere Junior M
Centro de Pesquisa e Gestão de Recursos Pesqueiros do Litoral Sudeste e Sul – CEPSUL – ICMBio, Itajaí, SC, Brazil.
Braz J Biol. 2011 Aug;71(3):755-61. doi: 10.1590/s1519-69842011000400022.
Age and growth studies for the scalloped hammerhead shark, Sphyrna lewini (Griffith and Smith, 1834) caught along the southern Brazilian coast, were based on ring measurements of vertebrae sections of 115 males, 116 females and 14 unknown sexed sharks between 48 and 344 cm total length (TL). The von Bertalanffy growth models were best fit using back-calculated data. The growth parameters obtained for males, were L∞ = 266 cm; K = 0.05/year; L0 = 47 cm. For females, L∞ = 300 cm; K = 0.05/year; L0 = 51 cm. An adult female reached 217 cm TL and was 31.5 years old. On the other hand, an adult male was 29.5 years old and measured 234 cm TL. Longevity estimate for males and females was 55 years. Therefore, S. lewini is a long-lived fish. Ageing precision, based on the IAPE index, was 5.6%. Marginal Increment analysis based on MIR index from hammerheads smaller than 105 cm, compared with the percentual of opaque and hyaline bands found per month ageing whole vertebrae, showed an annual ring formation, i.e., in winter.
对在巴西南部海岸捕获的无沟双髻鲨（Sphyrna lewini，由格里菲斯和史密斯于1834年命名）进行的年龄和生长研究，基于对115条雄性、116条雌性以及14条性别未知的鲨鱼的脊椎骨切片进行年轮测量，这些鲨鱼的全长在48至344厘米之间。通过反推数据，冯·贝塔朗菲生长模型得到了最佳拟合。雄性的生长参数为：L∞ = 266厘米；K = 0.05/年；L0 = 47厘米。雌性的生长参数为：L∞ = 300厘米；K = 0.05/年；L0 = 51厘米。一条成年雌性鲨鱼全长达到217厘米，年龄为31.5岁。另一方面，一条成年雄性鲨鱼年龄为29.5岁，全长234厘米。雄性和雌性的寿命估计为55年。因此，无沟双髻鲨是一种长寿鱼类。基于IAPE指数的年龄测定精度为5.6%。对全长小于105厘米的双髻鲨，根据MIR指数进行的边缘增量分析，与对整个脊椎骨每月进行年龄测定时发现的不透明带和透明带的百分比进行比较，结果显示每年形成一个年轮，即在冬季形成。
