Table 1.

Herbivorous fish biomass at high vs. low tide.

	High tide	Low tide	P value	Test
	Fish biomass (grams/150 m2)	Fish biomass (grams/150 m2)
Labridae (Scarinae)	3305 ± 1614	2734 ± 283
Acanthuridae	973 ± 143	2102 ± 666
Siganidae	240 ± 93	173 ± 84
Kyphosidae	71 ± 71	0 ± 0
Key browsers	70 ± 40	1434 ± 801	0.014	Mann-Whitney
Naso lituratus	67 ± 37	783 ± 367	0.014	Mann-Whitney
Naso unicornis	3 ± 3	651 ± 634	0.053	Mann-Whitney
Key grazers	1796 ± 214	2133 ± 410	0.431	t-test
Acanthurus triostegus	35 ± 10	30 ± 11	0.777	t-test
Ctenochaetus striatus	739 ± 122	519 ± 163	0.307	t-test
Chlorurus spilurus	612 ± 86	1352 ± 225	0.002	t-test
Scarus rivulatus	411 ± 205	231 ± 122	0.603	Mann-Whitney

We surveyed the abundance and size of herbivorous fishes across the available habitat at high tide (the entire reef; n = 12) and low tide (lagoons; n = 6). Fish biomass (grams; calculated using known length-weight relationships) per 150 m² area is reported (mean ± s.e.m.) for each herbivore family (upper section) and for species identified as the predominant browsers and grazers in the system (lower sections). Biomass at high vs. low tide was compared for each key species with a t-test or Mann-Whitney test.