Onset and development of aggressive behavior in the early life stages of the seven-band grouper Epinephelus septemfasciatus

Onset and development of aggressive behavior were observed in the early life stages of seven-band grouper Epinephelus septemfasciatus. Fish culture was divided into two terms: the first term, from hatch until 21 days after hatching (DAH); and the second term, from 21 DAH until settlement (65 DAH). During the second term the effect of different aeration rate on survival was investigated. Survival during the first term was 14.1 ± 7.1%. In the second term, survival in control tanks (aeration rate 200 mL/min) was 14.7 ± 10.2% and 18.8 ± 7.8% in the increasing aeration tanks (aeration rate 200–800 mL/min). Behavioral observations were conducted at about 8-day intervals and aggressive behavior was quantified by the frequency of chase behavior. Aggressive behavior was first observed on 52 DAH when pigment appeared on the dorsal area of the metamorphosing larvae (standard length 16.6 ± 6.0 mm). Aggressive behavior significantly increased from 59 DAH coinciding with the beginning of settlement.