. Atoll research bulletin. Coral reefs and islands; Marine biology; Marine sciences. 11 Figure 3: Number of transects needed to obtain a desired level of accuracy in estimating the median number of groupers per unit area (dashed line) and percent of all species observed (solid line) on the slope at Gaagandu (reference values are 23 for median density and 17 for total number of species observed). 100 T3 « J3 o n .a u 2. c 0-. 13 20 25 30 Number of Transects DISCUSSION Habitat can be viewed on a number of different scales. The density and distribution of groupers were related to within and among
. Atoll research bulletin. Coral reefs and islands; Marine biology; Marine sciences. 11 Figure 3: Number of transects needed to obtain a desired level of accuracy in estimating the median number of groupers per unit area (dashed line) and percent of all species observed (solid line) on the slope at Gaagandu (reference values are 23 for median density and 17 for total number of species observed). 100 T3 « J3 o n .a u 2. c 0-. 13 20 25 30 Number of Transects DISCUSSION Habitat can be viewed on a number of different scales. The density and distribution of groupers were related to within and among zone differences in habitat type. First, at the macro-scale, there were clear differences in the density and diversity of groupers at Gaagandu Island between the lagoon, crest, reef 1, and the slope. The slope had a higher sampling effort so that rarer species were more likely to be observed. These different zones vary in the amount of refuge available for groupers. The lagoon and crest had little relief. The lagoon at Gaagandu has been mined for coral (M. Haleem pers. com.). The lagoon at Olhugiri has not been mined extensively and still has large coral heads. The density at the lagoon at Olhugiri exceeded all sites except the slope at Gaagandu. This indicates that the lagoon at Gaagandu probably supported a much higher density of groupers prior to mining. Reef 1 had high relief, but consisted mainly of dense thickets of Acropora sp., which might have limited their use by certain species as the interstices were probably too small for movement and hiding (the dense thickets most likely inhibited the efforts of the surveyor as well). Harmelin-Vivien (1977) found that spur and groove reefs at 6-18 meters depth had more species of fish and a higher biomass than the deeper sloping Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly
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