MEPS 214:267-277 (2001)  -  doi:10.3354/meps214267

Spectral sensitivity of larval and juvenile coral reef fishes: implications for feeding in a variable light environment

Suresh D. Job1, Julia Shand2,*

1Department of Marine Biology, James Cook University of North Queensland, Townsville, Queensland 4811, Australia
2Department of Zoology, University of Western Australia, Crawley, Western Australia 6907, Australia

ABSTRACT: The spectral sensitivity of larval and juvenile stages of 3 species of coral reef fishes, Apogon compressus (Apogonidae), Pomacentrus amboinensis (Pomacentridae) and Premnas biaculeatus (Pomacentridae) has been investigated using feeding behaviour. Ontogenetic and taxonomic differences in spectral sensitivity were determined by establishing the minimum light intensity at which larvae and juveniles could strike prey at 12 restricted wavelength bands between 355 and 650 nm. Following construction of chromatic action spectra, the wavelength of maximum sensitivity (λmax) and the median wavelength (λP50) of the 3 species were found to be located close to 500 nm. All 3 species increased in sensitivity during growth, with A. compressus becoming the most sensitive prior to settlement. Ontogenetic shifts in spectral sensitivity towards longer wavelengths occurred in P. amboinensis and P. biaculeatus, but not in A. compressus. Spectral efficiency (wavelength-dependent efficiency of photon capture) was modelled for eutrophic and oligotrophic coral reef waters (Jerlov types Oceanic IA, Oceanic III and Coastal 1) at 2 different optical depths. Spectral efficiency was highest in the intermediate coral reef water type (JOIII) in all 3 larval fish taxa throughout early ontogeny, regardless of water depth. The results imply that the larvae would be able to feed across a broad spectrum of coral reef water types and depths.

KEY WORDS: Colour vision · Chromatic action spectrum · Feeding behaviour · Ontogeny · Pomacentridae · Apogonidae

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