Effect of food level on the growth and survival of laboratory-reared larvae of bay anchovy ( anchoa mitchilli Valenciennes) and scaled sardine ( harengula pensacolae Goode & Bean)

Abstract

The effect of food levels on the growth and survival of laboratory-reared larvae of scaled sardines ( Harengula pensacolae Goode & Bean) and bay anchovies ( Anchoa mitchilli Valenciennes) was determined. Wild zooplankton, most of which was copepod nauplii and copepodids, was used as food. H. pensacolae larvae grew 0.80 mm/day at a low (444 organisms/1) and high food level (1324 organisms/1). Survival was appreciably better (14.5%) at the low than (3.5%) at the high food level, 23 days after hatching. A. mitcchilli larvae grew faster at medium and high food concentrations. Average growth rates for three replicated experiments were 0.48 mm/day at low food (621–692 organisms/1), 0.50 mm/day a t medium food (1330–1688 organisms/1), and 0.54 mm/day at high food (2811–3323 organisms/1). Survival of A. mitchilli larvae, 20 to 28 days after hatching, ranged from 0.0 to 17.8% and was better at medium and high food levels than at the low food level. The resultsng indicate that 500 to 1000 copepod nauplii and copepodids/1 provided adequate food for rearing H. pensacolae but 1500–2000/1 were consistently required to rear A. mitchilli.