118 Asian Fisheries Science 33 (2020):118–127 Induced Spawning of Giant Trevally, Caranx ignobilis (Forsskål, 1775) using Human Chorionic Gonadotropin (hCG) and Luteinising Hormone- releasing Hormone Analogue (LHRHa) ©Asian Fisheries Society ISSN: 0116-6514 E-ISSN: 2073-3720 https:// doi.org/10.33997/j.afs.2020.33.2.004 MARIA THERESA MERCENE MUTIA, FREDERICK BUENSALIDA MUYOT*, MYLEEN LUNA MAGISTRADO, MYLA CELEMEN MUYOT, JANET LUCITO BARAL National Fisheries Research and Development Institute, 101 Mother Ignacia Ave., South Triangle, Quezon City 1103, Philippines *E-mail: fredbmuyot@yahoo.com | Received: 21/09/2019; Accepted: 16/05/2020 Abstract The giant trevally, Caranx ignobilis (Forsskål, 1775) was induced spawned at the National Fisheries Research and Development Institute, Taal, Batangas, Philippines to assess the possibility of captive breeding. Caranx ignobilis captive broodstock, six to eight-year-old (4.83 kg mean wt) were injected with: (a) 1,000 IU human chorionic gonadotrophin (hCG).kg -1 ; (b) 100 µg luteinising hormone-releasing hormone analogue (LHRHa).kg -1 ; (c) 5 mg carp pituitary extract (CPE).kg -1 ; and (d) No injection (Control). Ripe female fish was given two sequence intramuscular injections at 0600 to 0700 h and 1800 to 1900 h while male fish was given half dose injection at 1800 to 1900 h. One breeding set (1 female: 2 males) were released to spawn spontaneously in each of the four units of 40-ton circular tanks, done in five replications. Successful spawning was achieved in LHRHa- and hCG-injected fish at 28–30 g.L -1 salinity and 27.6–29.25 °C in March to April of 2011 and 2012. Spawning occurred 24–52 h after 2 nd injection and eggs hatched in 11–17 h. Fertilisation rate was significantly higher (P < 0.05) in LHRHa treatment (60.88 %) than hCG treatment (30.53 %). Mean spawned eggs, hatching rate and mean larvae produced were not statistically different (P > 0.05) between hCG (223,068 eggs.kg -1 breeder, 43.06 % and 41,547 larvae.kg -1 breeder, respectively) and LHRHa treatment (176,524 eggs.kg -1 breeder, 71.07 % and 56,040 larvae.kg -1 breeder, respectively). This is the first recorded captive breeding of C. ignobilis in the Philippines and an initial step towards developing the seed production technology for this new aquaculture species. Keywords: carangid species, captive breeding, hormone induction, seed production Introduction The giant trevally, Caranx ignobilis (Forsskål, 1775) of the Family Carangidae, is a highly prized food fish and game fish widely distributed throughout the tropical and sub-tropical regions of the Indian and Pacific Oceans (Smith-Vaniz, 1999). One of the most delicious food fishes in many parts of the world, the giant trevally is widely sought by commercial fishermen and professional game fish anglers because of its high market price and wide consumer preference (Honebrink, 2000). Due to its commercial importance and suitability for culture in captivity, C. ignobilis has been identified as a potential new species for aquaculture in several countries (AQUACOP et al., 1989; Liao, 2000; Abdussamad et al., 2008; Alaira and Rebancos, 2014). In the Philippines, C. ignobilis which is locally known as “maliputo”, is considered as a highly prized food fish and most popular indigenous migratory fish in Lake Taal, Philippines (Herre, 1958; Mercene, 1997; Mutia et al., 2004). Its development for aquaculture has always been one of the priority programs of the government (CNIFDP 2006) through its “maliputo” (C. ignobilis) development program. Production of seedstock is a continuing bottleneck for many marine fish species, and a major challenge in marine finfish hatchery technology is related to the complex life cycles of marine fish compared to freshwater fish (Watanabe et al., 2019). One of the limiting factors in the development of C. ignobilis as an aquaculture species is the lack of a seed production technology for at present, wild sourced seedstock has been used for culture. Although Taiwan is reported as