Reproductive Biology and Population Dynamics of Largehead Hairtail (Trichiurus lepturus Linnaeus, 1758) in Babuyan Channel, Philippines

Trichiurus lepturus is a highly valuable species in the commercial fishing industry along the Babuyan Channel, a significant fishing ground in the Philippines. Data was collected from April 2018 to March 2020 at the established National Stock Assessment Program (NSAP) fish landing centers along the Babuyan Channel. The population parameters and gonadosomatic index were analyzed using FAO-ICLARM Fisheries Stock Assessment Tools II software and a five-point scale maturity index, respectively. A total of 2,597 fish samples were collected, with a higher number of female individuals. The mean fecundity observed was 48,576 eggs, with spawning occurring mainly in May (1st peak) and October to November (2nd peak). The majority of the observed females were at Stages IV and V, indicating that the Babuyan Channel is a spawning area. The length at first maturity (Lm) was 44.61 cm for males and 55.94 cm for females. The fishing mortality value (F = 1) is slightly higher than the natural mortality value (M = 0.59), indicating a slight increase in fishing pressure. The exploitation rate is E = 0.63, which is higher than the 0.5 sustainable level of exploitation. Thus, to protect and conserve the stock, management options such as banning active gear, using environment-friendly fishing gears, strict implementation of fishery laws, and establishing additional marine protected areas to support species productivity are recommended.