Implications of feeding frequency, prey size and condition, and intraspecific competition for the commercial aquaculture of the nudibranch Berghia stephanieae

Abstract

AbstractMarine ornamental aquaculture is a growing industry. Although most species are cultured for aesthetic purposes, there is increasing interest in organisms that provide functional services. Nudibranchs provide an example in which they act as biological controls by consuming aquaria pests. Berghia stephanieae is a commercially relevant nudibranch that feeds on Exaiptasia anemones, which overgrow sessile invertebrates. However, information pertaining to B. stephanieae feeding habits remains unaddressed. Therefore, this study investigated the following: (a) the effect of feeding frequency on fecundity, (b) optimum prey size, (c) the ability to feed on prey fragments, and (d) the influence of intraspecific competition. Distinct feeding frequencies were tested and embryos produced were quantified; growth of nudibranchs offered different anemone sizes was measured; whole and fragmented anemones were offered, with preference recorded; and growth and mortality of juvenile nudibranchs were recorded in the absence and presence of adult conspecifics. Results show that feeding daily produced the highest number of embryos. Juveniles fed on medium‐sized anemones showed the highest growth rate. Smaller juveniles were unable to feed on whole anemones and preferred fragmented anemones. Juvenile growth and survival decreased in the presence of adults. To maximize production, breeders must feed broodstock daily, provide medium‐sized anemones or fragments, and segregate juveniles from adults.