Abstract
The rates of growth, gut evacuation and ingestion of Pacific chub mackerel (Scomber japonicus) larvae were determined under experimental rearing conditions. Temperature was shown to have a significant effect on the growth, evacuation and ingestion rates. The daily specific growth rate (in weight) ranged from 16.8% at 16°C to 52.6% at 25°C. Instantaneous gastric evacuation rates ranged from 0.68 to 1.44 between 16 and 22°C, respectively. Daily ingestion ranged from 29.1% (10 days after hatching; DAH at 16°C) to 126.4% (15 DAH at 22°C) body dry weight. The developmental stage (daily age) also affected ingestion and growth. Daily ingestion rate increased from 10 DAH to 15 DAH at each temperature, while gross growth efficiency (mean value of 3 temperatures) decreased from 48.8% on 10 DAH to 28.4% on 15 DAH. These high ingestion and fast growth characteristics during the early life stage of Pacific chub mackerel well agreed with other scombrid species. Bioenergetics to determine growth rate were discussed in relation to changes in temperature.
