Proportional growth and maturation in Penaeus indicus

Abstract

A least squares estimation of inflected linear regression is used to interpret the relationships between carapace length (CL) and total length, abdominal length and abdominal width respectively, in Penaeus indicus and Metapenaeus monoceros. In both species well-defined inflection points with significant differences between slopes are evident in each of these relationships. In P. indicus males, changes in proportional growth are evident at 27.5–29.3mm CL. In females two inflection points are evident, one at 28.8–31.0mm CL and another at 39.7mm CL. Similarly, in M. monoceros, males show a proportional growth change at around 22mm CL and females at 27mm and 34mm respectively. These changes in P. indicus occur at the approximate sizes at which mating maturity and ovarian maturity are attained, suggesting that they may be linked.


Keywords: Penaeus indicus; Metapenaeus monoceros; morphometrics; inflected regression; maturation


(Afr J Aqua Sci: 2000 25: 33-36)