Changing Patterns of Microhabitat Utilization by the Threespot Damselfish, Stegastes planifrons, on Caribbean Reefs

Abstract

BackgroundThe threespot damselfish, Stegastes planifrons (Cuvier), is important in mediating interactions among corals, algae, and herbivores on Caribbean coral reefs. The preferred microhabitat of S. planifrons is thickets of the branching staghorn coral Acropora cervicornis. Within the past few decades, mass mortality of A. cervicornis from white-band disease and other factors has rendered this coral a minor ecological component throughout most of its range.Methodology/Principal FindingsSurvey data from Jamaica (heavily fished), Florida and the Bahamas (moderately fished), the Cayman Islands (lightly to moderately fished), and Belize (lightly fished) indicate that distributional patterns of S. planifrons are positively correlated with live coral cover and topographic complexity. Our results suggest that species-specific microhabitat preferences and the availability of topographically complex microhabitats are more important than the abundance of predatory fish as proximal controls on S. planifrons distribution and abundance.Conclusions/SignificanceThe loss of the primary microhabitat of S. planifrons—A. cervicornis—has forced a shift in the distribution and recruitment of these damselfish onto remaining high-structured corals, especially the Montastraea annularis species complex, affecting coral mortality and algal dynamics throughout the Caribbean.

Loss of Structural Complexity in Staghorn Coral Rubble Habitats Influences the Density of Damselfish in Dry Tortugas National Park, Florida, USA

“…Although several factors in addition to structural complexity have been previously linked to reef fish density, including the nearby presence of live coral, benthic macroalgae, depth, fish community, and relative fishing pressure (Bell and Grazin, 1984;Chabanet et al, 1997;Ö hman and Rajasuriya, 1998;Jones et al, 2004;Nagelkerken et al, 2005;Medeiros et al 2010;Precht et al 2010), these factors are similar between our study sites (J. Grim et al, unpubl.).…”

“…Thus far, reports of damselfish abundance within the Gulf of Mexico have generally been limited to the ecology of damselfishes occupying moderately affected or pristine lowenergy patch reefs (e.g., Emery, 1973;Wallman et al, 2004;Precht et al, 2010). Previously, we reported that damselfish densities vary significantly between live strands of very highly rugose staghorn coral (Acropora cervicornis) and dead, very-low-rugosity A. cervicornis rubble (Wilkes et al, 2008).…”

Unusual “Knob-Like Chimney” Growth Forms on Acropora Species in the Caribbean

“…In contrast, others have suggested that damselfish abundances have historically been high (Kaufman, 1981). Moreover, others argue that damselfish densities are related to the availability of microhabitats rather than predator abundance (Precht et al, 2010). In Cocalito, the fish biomass is dominated by grunts (Haemulidae ∼100 g/m 2 ), with much lower biomass of snappers (Lutjanidae ∼20 g/m 2 ), and a similar biomass of angelfish (Pomacanthidae ∼16 g/m 2 ) (Supplementary Figure 3).…”

“…as disease outbreaks have caused massive mortality (Aronson and Precht, 2001). However, the remaining Acropora colonies continue to be the preferred microhabitat of damselfish and disease prone vectors (Lirman, 1999;Precht et al, 2010;Bruckner and Bruckner, 2015). On many occasions, damselfish bites and white pox disease have been easily confused, but white pox tends to manifest as irregular lesions, rather than perfectly symmetrical circular lesions (Pollock et al, 2011;Bruckner and Bruckner, 2015).…”

“…Further investigations on the spatial patterns of predation by damselfish and polychaetes (fireworms), as well as their abundances, recruitment and relationship to knob growth patterns is warranted. Monitoring present lesions and conducting new coral-wound regeneration experiments in the field under different environmental conditions may reveal the aspects that are key to recovery and algal/coral interactions (Precht et al, 2010;Wolf et al, 2014). These studies could be conducted using field assessments such as permanent transects, colony tagging, and lesion monitoring using photographs and videos.…”