Effect of high nitrate-N on the growth and survival of juvenile and larval anemonefish, Amphiprion ocellaris

Abstract

Growth and survival of juvenile and larval anemonefish, Amphiprion ocellaris, were compared at low and high levels of nitrate-N. Two 800-l pumped aquarium systems with Instant Ocean ® as the culture medium were used. Sodium nitrate was added to raise the level of NO 3-N in the high-nitrate system to 100 mg NO 3-N/l. Three groups of juveniles, aged 72 and 40 days, and two tanks of newly-hatched larvae, were tested. Survival of the juveniles was 100% after 84 days, but growth was reduced in the high-nitrate system. Survival of larvae in low- and high-nitrate systems at 21 days were 37 and 34%, respectively, but delayed metamorphosis occurred in 97% of the fish in the low-nitrate system, compared with only 40% in the system with high nitrate. The survival of larvae to 72 days were 37 and 12%, respectively. The high nitrate level did not affect juvenile survival, but reduced growth. The rate of larval metamorphosis, and also subsequent survival and growth, were reduced in the high-nitrate system.