Growth patterns and longevity of the pandalid shrimp Plesionika izumiae (Decapoda: Caridea)

Abstract

ABSTRACT The pandalid Plesionika izumiae Omori, 1971 is widely distributed in the west Pacific regions. This is a relatively common shrimp in the coastal waters of Japan, except off northern Honshu and Hokkaido, and is commercially important for small-scale bottom seine fishery. The growth patterns and longevity of P. izumiae were estimated in Kagoshima Bay, southern Japan, using time series of the length-frequency distributions during February 2007 to January 2011. Carapace length ranged from 4.4–14.5 mm in males and 4.0–14.7 mm in females. Both males and females were first recruited in autumn (October—November) with modal size around 7.0 mm carapace length. The growth was best described by the Pauly and Gaschutz equation as Lt = 11.95[1 - exp{-3.991(t/12 - 0.118) - (2.866/2π) sin(2π(t/12 - 0.955))}] for males and Lt = 12.73[1 - exp{-4.084(t/12 - 0.142) - (2.646/2π) sin(2π(t/12 - 0.912))}] for females. Females grew faster and reached a larger size at the same age than males. Monthly growth rate was lower...