Combined direct and indirect impacts of warming on the productivity of coral reef fishes

Abstract

Ocean warming is already causing widespread changes to coral reef ecosystems worldwide. Warming is having direct and indirect impacts on food webs, but their interaction is unclear. Warming directly affects fishes and invertebrates by increasing their metabolic rate, resulting in changes to demographic processes such as growth rates. Indirect effects involve a loss of reef habitat quality as coral bleaching reduces the availability of refuges. We used a size‐structured dynamic energy budget model of fishes and invertebrates, coupled to a spatially explicit model of coral and algae, to explore potential changes to ecosystem function with warming. Modeled changes in biomass for +3°C of warming were found to be controlled predominantly by the direct effects of warming on growth rates, rather than by indirect effects via the changed coral habitat. Crucially for fisheries, the biomass of predators decreased by at least 50% with +3°C of warming, and productivity of predators decreased by at least 60%.

Is the variability of butterflyfish species domination driven by its habitat conditions?

“…However, Chelmon rostratus and C. trifasciatus were not significantly had a relationship with the variation of SST (p = 0.12 and p = 0.058, respectively). Temperature variations will also affect reef fishes through production rate decrease [3], and the elevation of temperature could threaten the future species diversity wherein predicting the habitat suitability is more important than the species tolerance to temperature [24]. Relation between temperature and reef fish could be predicted the species abundance response to future temperature change, however, the alga shifting in coral zones also affected by climate change also influences the abundance distribution of fish [25].…”

“…Among two types of reef fish e.g., specialist and generalist, wherein some fish with a specialist type has distributions were constrained by temperature, and the benthic habitat availability limited others. Variations in benthic habitats and temperature might describe these environmental changes and could drive the fish responses [2], the temperature change has also affected the fish by increasing their metabolite and growth [3]. Butterflyfish (family Chaetodontidae) are closely related to coral reefs, and some fish rely on live coral.…”

Habitat‐specific impacts of climate change on the trophic demand of a marine predator

“…However, known prey items are found in these habitats and previous studies have shown grouper remain resident in home reefs (Blincow et al, 2020; Dahlgren et al, 2016). Finally, we assume that increasing temperatures have a positive effect on prey productivity, but there are possible scenarios where it has negative effects such as decreased fish growth rates and indirect changes to reef state, such as a loss of coral cover and/or a loss of rugosity (Millington et al, 2022). When considering the impact top predators may have on their ecosystems, it is important to consider how habitat complexity may strengthen or weaken predator–prey interactions (Johnson, 2006), and investigate the hunting efficiency of predators across habitats.…”