Effects of natural food availability on larval condition of Balanus glandula in the laboratory and the field

Abstract

Food availability in the coastal oceanic environment off Oregon was shown to limit energy reserves and developmental rates of barnacle nauplii in some experiments but not others. In laboratory studies, when naupliar feeding rates measured by gut contents and fecal pellet production rates were similar for larvae raised on natural and supplemented rations, larval lipid content and development were similar between these rations (2 trials). When feeding rates of nauplii differed between food treatments so did lipid content and development (2 trials). A parallel study sampled lipid content and size of naturally occurring larvae and chlorophyll-a in the water column. While chlorophyll-a was an accurate measure of food availability measured by fecal pellet production, it explained little (2-4%) of the variation in cyprid quality. Efforts to understand variation in quality of natural populations of larvae will need to combine the effects of genetic variation, feeding history, and food quality.