Age and growth of Pennahia argentata in the offshore waters of southern Zhejiang

Abstract:

To understand the age and growth of Pennahia argentata, 655 specimens of Pennahia argentata were collected from the offshore waters of southern Zhejiang. Age determination by sagitta otolith, and the growth function equation were fitted using Logistic, Gompertz and Von Bertalanffy growth function to analyze the structures and growth characteristics of the collected samples. It was found that:(1) Body length of samples ranged from 40 to 200 mm with a mean body length of (96.73±26.27) mm, and body weight varied from 0.8 g to 185.9 g with a mean body mass of (23.79±23.67) g; (2) The relationship between body length (L) and body mass (W) was not significantly different between males and females (P>0.05), and the function of body length-body mass was expressed as W=2×10^-5×L^3.0021 (R²=0.9800); (3) 157 otoliths were analyzed, and they aged between 0 and 4, age 0 being the dominant age group, accounting for 65.60%, while age 1 accounting for 18.47%, age 2 accounting for 6.37%, age 3 accounting for 7.64%, and age 4 accounting for only 1.91%; (4) Body length (L) and sagitta otolith short radius (S_R) was not significantly different between males and females (P>0.05), and the relationship was expressed as S_R=0.0108 L-0.310 6 (R²=0.8766); (5) Von Bertalanffy growth function seemed to be the most adequate model to describe growth based on the Akaike information criterion (AIC) test, with resulting growth parameters of L_∞=204.2 mm, K=0.4 per year and t₀=-1.56. The inflection point of the growth curve occurred at 1.19 years with a body length of 136 mm and body weight of 50.8 g.