**3. Results**

In total, 213 fishes from seven of the eight indicator families and 845 hard coral colonies from 22 genera were recorded. Across all sites, the *Acanthuridae* (surgeon fishes) were the dominant family in terms of individuals, followed by the *Chaetodontidae* (butterflyfishes). From the other families, relatively few individuals were recorded (Table 1).


**Table 1.** Mean number of fish families per site ± standard deviation.

For corals, the most abundant genera were massive *Porites* followed by *Acropora* (Table 2). The benthic analyses showed a dominance of macroalgae and turf algae at all sites (Table 2). Hard corals, sand, seagrass, and rubble also formed a large part of the benthos, whereas herbivorous invertebrates (mainly sea urchins), *Halimeda* algae and soft corals were less abundant (Table 3).





Based on the Akaike Information Criterion (AICC), the best supported model for coral genus richness was one in which seagrass and macroalgae both had negative effects (Table 4). Coral genus richness doubled as macroalgae cover dropped from 69 to 2% (Figure 2A). The data indicated, on average, a loss of one coral genus for every additional 20% increase in the cover of macroalgae. Coral genus richness was similarly negatively related to seagrass substrate cover (Figure 2B). In the second- and third-best models, the presence of turf algae had an additional negative effect on coral genus richness (Table 4). In the best supported model of the factors influencing coral cover, (log-transformed) herbivorous invertebrate abundance and fish family richness both showed significant positive effects (Table 4). On average, there were twice as many corals on the transects where invertebrate numbers were the highest compared to those where it was lowest (Figure 2C). Similarly, we observed a significant increase in coral cover with increasing fish species richness (Figure 2D). However, in the second-best model, it was fish abundance instead of the fish family richness that showed a positive relationship. In the third model, turf algae cover had an additional negative impact (Table 4).

**Table 4.** Results of the AICC based model selection for the environmental variables coral genus richness (CGR) and coral cover (CA), using the predictor variables AMAC (macroalgae), ATRF (turf algae), FABUND (fish abundance), FFM (fish family richness), Lg1(INV) (log-transformed herbivorous invertebrate abundance), and SGR (seagrass). '\*' *p* < 0.05; '\*\*' *p* < 0.01; '.' 0.05 < *p* < 0.10. Successive lines show the results for the best supported, and second- and third-best supported models.


Fish family richness was best explained by a model in which coral cover had a positive impact, whereas herbivorous invertebrate abundance had a negative impact (Table 5). Fish family richness tripled along a gradient of coral cover from 2 to 69 percent (Figure 3A), whereas there were approximately twice as many fish species on sites with low invertebrate abundance as on those with high abundance (Figure 3B). In the second-best supported model, seagrass cover appeared to have an additional negative impact, whereas in the thirdbest model coral cover alone influenced the family richness of fish. In the best model for fish abundance (Table 5, Model B), macroalgae and coral cover both had positive effects on fish abundance. There were more than twice as many fish on the most coral rich site as on the least coral rich site (Figure 3C), while fish abundance also doubled along a gradient of macroalgae cover from 1 to 69% (Figure 3D). The second-best supported model explaining fish abundance showed a negative impact of turf algae and seagrass, whereas the third-best model contained only the positive impact of macroalgae abundance.

**Figure 2.** Relationship of different substrate variables to coral genus richness and coral cover at the reefs in Gazi Bay. Black lines correspond to model prediction analysis, orange lines represent the estimates derived from multiple regression analysis. Coral genus richness decreased with increasing macroalgae (**A**) and seagrass cover (**B**). Coral cover increased with increasing herbivorous invertebrate abundance (**C**) and fish family richness (**D**). Grey data points show individual values on each of the 30 transects. The dashed line indicates that parameter estimates are only marginally significant (0.05 < *p* < 0.10).

**Table 5.** Results of the AICC based model selection for fish family richness (FFR) and fish abundance (FA) using the key predictor variables AMAC (macroalgae), ATRF (turf algae), CA (coral cover), Lg1(INV) (log-transformed invertebrate abundance), and SGR (seagrass). '\*' *p* < 0.05; '.' 0.05 < *p* < 0.10. Successive lines show the results for the best supported, and second- and third-best supported models.


**Figure 3.** Relationship of different environmental factors to fish family richness and fish abundance. The orange lines represent the estimates derived from multiple-regression analysis. Fish family richness increases with increasing coral cover (**A**) and decreases with increasing invertebrate/sea urchin abundance (**B**). Fish abundance increases with increasing coral cover (**C**) and macroalgae cover (**D**). Grey dots show individual measures of response variables on the 30 transects.
