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Baselines and benchmarks (B&Bs) are needed to evaluate the ecological status and fisheries potential of coral reefs. B&Bs may depend on habitat features and energetic limitations that constrain biomass within the natural variability of the environment and fish behaviors. To evaluate if broad B&Bs exist, we compiled data on the biomass of fishes in ~1000 reefs with no recent history of fishing in 19 ecoregions. These reefs spanned the full longitude and latitude of Indian and Pacific Ocean reefs and included older high-compliance fisheries closures (>15 yr closure) and remote reef areas (>9 h travel time from fisheries markets). There was no significant change in biomass over the 15 to 48 yr closure period but closures had only ~40% of the biomass (740 kg ha^-1, lower confidence interval [LCI] = 660 kg ha^-1, upper confidence interval [UCI] = 810 kg ha^-1, n = 157) of remote tropical reefs (1870 [1730, 2000] kg ha^-1, n = 503). Remote subtropical reefs had lower biomass (950 [860, 1040] kg ha^-1, n = 329) than tropical reefs. Closures and remote reef fish biomass responded differently to environmental variables of coral cover, net primary productivity, and light, indicating that remote reefs are more limited by productivity and habitat than closures. Closures in fished seascapes are unlikely to achieve the biomass and community composition of remote reefs, which suggests fisheries benchmarks will differ substantially from wilderness baselines. A fishery benchmark (B₀) of ~1000 kg ha^-1 adjusted for geography is suggested for fisheries purposes. For ecological purposes, a wilderness baseline of ~1900 kg ha^-1 is appropriate for including large and mobile species not well protected by closures.

Item Type:	Refereed Article
Keywords:	Reef Life Survey, citizen science, MPAs, reef fish, baselines, coral reef fish, fisheries and ecological indicators, pristine or virgin biomass, sustainability
Research Division:	Biological Sciences
Research Group:	Ecology
Research Field:	Marine and estuarine ecology (incl. marine ichthyology)
Objective Division:	Environmental Management
Objective Group:	Terrestrial systems and management
Objective Field:	Assessment and management of terrestrial ecosystems
UTAS Author:	Edgar, GJ (Professor Graham Edgar)
UTAS Author:	Stuart-Smith, RD (Dr Rick Stuart-Smith)
ID Code:	131297
Year Published:	2019
Funding Support:	Australian Research Council (LP100200122)
Web of Science® Times Cited:	35
Deposited By:	Ecology and Biodiversity
Deposited On:	2019-03-12
Last Modified:	2020-01-06
Downloads:	31 View Download Statistics