Feeding preferences of adult and juvenile rabbitfish Siganus argenteus in relation to chemical defenses of tropical seaweeds

• Published in: Marine ecology. Progress series (Halstenbek) Vol. 60; no. 1/2; pp. 23 - 34
• Main Authors: Paul, Valerie J., Nelson, Stephen G., Sanger, Herling R.
• Format: Journal Article
• Language: English
• Published: Inter-Research 01-01-1990
• Subjects: Algae; Chemicals; Coral reefs; Feeding preferences; Herbivores; Herbivorous fishes; Marine; Marine ecology; Metabolites; Seaweeds; Siganus argenteus; Teleostei; Young animals; Guam
• ISSN: 0171-8630; 1616-1599
• DOI: 10.3354/meps060023

The role of algal secondary metabolites in determining feeding preferences of adult and juvenile rabbitfish Siganus argenteus was examined in outdoor tanks on Guam. Secondary metabolites could not explain the preferences of these herbivores, although the presence of secondary metabolites appeared to account for the low palatability of some seaweeds, such as Tydemania expeditionis and Microcoleus lyngbyaceus. Other species, including Desmia hornemanni and Halimeda discoidea, that contained secondary metabolites with feeding-deterrent properties were of medium preference. Further species that produced secondary metabolites, including Asparagopsis taxiformis, Caulerpa spp., Chlorodesmis fastigiata, Dictyota spp., and Liagora farinosa were rapidly eaten, and neither their extracts nor their isolated metabolites significantly deterred grazing. Responses to algal chemistry differed between adults and juveniles. Juvenile S. argenteus were not deterred by extracts of T. expeditionis, Halymenia durvillaei, H. discoidea, and Enhalus acoroides, or the isolated metabolites chlorodesmin and flexilin that deterred the adults. As regards morphological defenses, several calcified seaweeds were of medium preference for both adult and juvenile rabbitfish; however, none of the highpreference seaweeds were calcified, and calcification and toughness were associated with low feeding preference.