Editorial Type:
Article Category: Research Article
 | 
Online Publication Date: 01 Sept 2003

Visual Biology of Hawaiian Coral Reef Fishes. II. Colors of Hawaiian Coral Reef Fish

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Page Range: 455 – 466
DOI: 10.1643/01-055
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Abstract

The colors of 51 species of Hawaiian reef fish have been measured using a spectrometer and therefore can be described in objective terms that are not influenced by the human visual experience. In common with other known reef fish populations, the colors of Hawaiian reef fish occupy spectral positions from 300–800nm; yellow or orange with blue, yellow with black, and black with white are the most frequently combined colors; and there is no link between possession of ultraviolet (UV) reflectance and UV visual sensitivity or the potential for UV visual sensitivity. In contrast to other reef systems, blue, yellow, and orange appear more frequently in Hawaiian reef fish. Based on spectral quality of reflections from fish skin, trends in fish colors can be seen that are indicative of both visually driven selective pressures and chemical or physical constraints on the design of colors. UV-reflecting colors can function as semiprivate communication signals. White or yellow with black form highly contrasting patterns that transmit well through clear water. Labroid fishes display uniquely complex colors but lack the ability to see the UV component that is common in their pigments. Step-shaped spectral curves are usually long-wavelength colors such as yellow or red, and colors with a peak-shaped spectral curves are green, blue, violet, and UV.

Copyright: The American Society of Ichthyologists and Herpetologists
 Fig. 1.
 Fig. 1.

Examples of Hawaiian fish colors plotted as percent reflectance relative to a white “Spectralon” standard (Endler, 1990; Marshall, 1996). The colors of the curves are approximate matches to the color in life as seen by humans. Note that color reflectance takes two forms: step-shaped and peak-shaped. Colors with one of either of these shapes are classed as simple, colors with two or more of either shape (i.e., two peaks or a peak and a step or two peaks and a step as in Chlororus sordidus) are classed as complex (Marshall, 2000a). For each example, the numbers on the body areas in the photographs correspond to the numbered reflection curves for the fish. (A–B) Zanclus cornutus. (C–D) Chromis ovalis. (E–F) Chlororus sordidus. (G–H) Coris gaimard. The photographs show close-ups of body regions in this brilliantly colored fish. They are (clockwise) the dorsal fin, the base of the pectoral fin, and the tail close to the caudal peduncle


 Fig. 2.
 Fig. 2.

The 50% reflection points (R50) for step-shaped colors (A) and positions of the peak in peak-shaped colors (B) in Hawaiian reef fish. The curve plotted through the data is a five-point moving average with 1-nm wide points


Received: 13 Feb 2001
Accepted: 01 Feb 2003
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