At the end of each experiment, the contents of individual aquariawere collected on a 25 m mesh screen and washed into separate50 mL vials containing 4% formaldehyde solution in buffered sea-water. Survival and growth were estimated by removing triplicate1 mL sub-samples from each 50 mL vial and examining the contentsusing an optical microscope (200X). The number of surviving larvaewere counted and the shell length (APM) of 20 random individu-als was measured. Relative larval production, or yield mL−1, wascalculated by multiplying initial density by mean survival. The nor-mality of raw data was assessed using probability plots of residual