Age-based growth dynamics of solitary and schooling Snapper <i>Chrysophrys auratus</i>; a comparative analysis

This study investigates the age and growth-based population dynamics of snapper (Chrysophrys auratus) in the SNA1 management area, comparing recreationally and commercially caught fish as proxies for solitary and schooling stocks, respectively. Fishing gear selectivity influenced age and size distribution between the two groups, with recreationally caught snapper exhibiting a wider range (3-28 years; 260-830mm SL) compared to commercially caught snapper (2-13 years; 240-439mm SL). The two main von Bertalanffy Growth Function (VBGF) parameters of asymptotic length (L∞) and growth coefficient (K), indicated that the average asymptotic length for recreationally caught snapper was slightly greater at 433.48 mm (SL), in contrast to 406.51 mm for those caught commercially. However, both groups exhibited comparable growth coefficients of 0.21 and 0.22, respectively. Likelihood ratio tests assessing growth parameter differences between the two groups showed no statistically significant variation. Our findings suggest that despite different fishing pressures, the growth profiles of solitary and schooling snapper are the same, highlighting the importance of implementing uniform management strategies for both the recreational and commercial sectors.