Age, growth and population aspects of Fistularia commersonii (Rüppell, 1838) from the Eastern Mediterranean region, Alexandria, Egypt

This study is a pioneering effort to investigate demographic characteristics and assess the stock status of Fistularia commersonii in the Mediterranean Sea. A number of 746 specimens were collected from trawling catches in the west of Alexandria, with total lengths ranging from 24.1 cm to 107.5 cm. Females exhibited maximum length (mean = 58.96 ± 16.809). The collected specimens were assorted into five age groups, where the first and second groups—with mean lengths of 42.82 ± 3.46 and 57.52 ± 6.12, respectively— showed maximum frequencies of 38.16 and 34.67 %, respectively. A long life span (tmax = 16.02 yr) was calculated for the fish. A high asymptotic length and weight were observed (L∞= 136.194 cm and W∞= 2105 g) with a slow growth rate of K = 0.187 yr−1. Adaptability to the zonal habitat and good growth as well were clarified, where the growth performance indexes; Φ‘L = 3.54 and Φ‘W = 1.49. The length at first capture (Lc) was disclosed at 40.82 cm, the length of recruitment (Lr) at 34.33 cm, and the optimum length at 83.21 cm. Mortality coefficients were estimated—i.e., the natural mortality (M) = 0.358 yr−1 and the fishing mortality (F) = 0.582 yr−1, with a highlight of overfishing in view of biological reference points (Fopt = 0.179 yr−1 and Flimit = 0.239 yr−1). The current exploitation rate (E = 0.619) strongly confirmed stock overexploitation. As revealed, the maximum yield per recruit (Y/R) can be attained by reducing (F) and (E) by a rate of 31.27 and 48.47 %, respectively. The findings of this study advocate for limiting fishing efforts to preserve the population and an extensive examination of feeding behavior to clarify the potential impact on native taxa.