Dataset: Phillips_2011 - Experiment 2 Larval Velum Size

In this experiment, larval growth and metamorposis was tested using different food levels.

Larvae hatched on October 10, 2009 and ~50 were distributed into each tubs on 500mL filtered sea water (FSW). Because the greatest metamorphic success was in the Isochrysis galbana treatment during experiment 1, only that species was used in this experiment.

Three food densities were created high food (4 x 104 cells mL-1 ), low food (4 x 103 cells mL-1 ) plus an Unfed treatment in which larvae were raised in FSW. The height and width of fully extended velums on live larvae 3-, 6- and 9-day post-hatch were measured. Approximately 20 larvae from each replicate container were pipetted into small petri dishes with FSW, under a dissecting microscope. When larvae were first introduced to the dish their vela were withdrawn. After approximately 1 min, the vela were extended and the larvae began to swim. The larvae were measured when the vela was fully extended vela and the larvae were still on the bottom of the dish and in focus (i.e. before swimming). Because this was logistically challenging, numbers measured per container and per treatment varied and sample sizes were relatively low (N per food treatment = 6–20, after pooling larvae across replicate containers).