DOI: 10.2478/cjf-2025-0018
Original scientific paper
REPRODUCTIVE CHARACTERISTICS OF MACKEREL SCAD Decapterus macarellus (CUVIER, 1833) IN NORTHERN PHILIPPINE WATERS
2025, 83 (4) p. 167-175
Melanie Villarao, Angel Encarnacion
Abstract
Decapterus macarellus is a highly valuable species in the Philippines' municipal and commercial fishing industry, particularly in the northern Philippine waters in the Babuyan Channel fishing ground. The study determines the reproductive characteristics including the sex ratio, gonadal somatic index (GSI), gonad maturity, and size at maturity (Lm, and L95). Samples were collected in Babuyan Channel fishing ground from April 2018 to March 2020 and were analyzed using the FAO-ICLARM Fisheries Stock Assessment Tools II software and a five-point scale maturity index. D. macarellus is present throughout the year in the fishing ground with noted peaks from April to July. An unbalanced sex ratio was found between the female (1:18) and male (1). The mean fecundity was 25,546 eggs. The Gonadosomatic index revealed that the spawning season of D. macarellus occurs throughout the year with an observed prolonged spawning with a notable peak of spawning during the northeast monsoon. The length at maturity (Lm) was 14.15 cm and L95 of 17.60 cm. Of all the fishing gear catching the species, beach seine catches most of the juveniles. To protect and conserve the stock, management options like establishing additional Marine Protected Areas to support the fish populations and productivity of the species and reduction of fishing efforts.