Marques S, Ferreira B P
Universidade Federal de Pernambuco, Departamento de Oceanografia, Recife, 50740-550, Brazil.
J Fish Biol. 2016 Jul;89(1):1009-25. doi: 10.1111/jfb.12923. Epub 2016 Apr 13.
This paper presents results on the age, growth and population structure of a small grouper, the mutton hamlet Alphestes afer, and discusses the observed size and age structure patterns in relation to reproductive strategies among the epinephelids. Ages were determined by examination of sectioned otoliths, which showed a distinct pattern of alternating translucent and opaque zones that formed annually, as validated with tetracycline labelling. The von Bertalanffy growth function was adjusted to the length-at-age data of the males and females, but no significant differences were observed between the resulting parameters. The females, however, were older at given sizes and attained larger sizes and ages, with a maximum observed longevity of 13 years and a total length (LT ) of 26 cm, while the males attained maximum longevities of only 10 years and a 22 cm maximum LT . The LT and age range for the sex change was 16-25 cm and 3-11 years. The total mortality rate (Z) was estimated to be 0·55 for females and 0·82 for males. With the males younger and smaller than the females, this species differed from the pattern commonly observed for protogynous epinephelids. Males had slower growth after maturation, probably due to energy allocation to sperm production during sexual development. This study shows that demography is an important tool to understand the pathways for reproductive strategies in grouper populations.
本文展示了关于小鳞石斑鱼（Alphestes afer）的年龄、生长和种群结构的研究结果，并讨论了在石斑鱼中观察到的大小和年龄结构模式与繁殖策略的关系。通过检查切片耳石确定年龄，耳石呈现出每年形成的明显交替的半透明和不透明带模式，这已通过四环素标记得到验证。将冯·贝塔朗菲生长函数应用于雄性和雌性的年龄体长数据，但所得参数之间未观察到显著差异。然而，雌性在相同体长时年龄更大，达到的体长和年龄也更大，观察到的最大寿命为13年，全长（LT）为26厘米，而雄性的最大寿命仅为10年，最大LT为22厘米。性转变时的LT和年龄范围为16 - 25厘米和3 - 11年。估计雌性的总死亡率（Z）为0.55，雄性为0.82。由于雄性比雌性更年轻、更小，该物种不同于常见的雌性先熟石斑鱼模式。雄性成熟后生长较慢，可能是由于在性发育过程中能量分配用于精子生产。这项研究表明，种群统计学是理解石斑鱼种群繁殖策略途径的重要工具。
