title: Growth anomalies on the coral genera Acropora and Porites are strongly associated with host density and human population size across the Indo-Pacific.
abstract: Growth anomalies (GAs) are common, tumor-like diseases that can cause significant morbidity and decreased fecundity in the major Indo-Pacific reef-building coral genera, Acropora and Porites. GAs are unusually tractable for testing hypotheses about drivers of coral disease because of their pan-Pacific distributions, relatively high occurrence, and unambiguous ease of identification. We modeled multiple disease-environment associations that may underlie the prevalence of Acropora growth anomalies (AGA) (n = 304 surveys) and Porites growth anomalies (PGA) (n = 602 surveys) from across the Indo-Pacific. Nine predictor variables were modeled, including coral host abundance, human population size, and sea surface temperature and ultra-violet radiation anomalies. Prevalence of both AGAs and PGAs were strongly host density-dependent. PGAs additionally showed strong positive associations with human population size. Although this association has been widely posited, this is one of the first broad-scale studies unambiguously linking a coral disease with human population size. These results emphasize that individual coral diseases can show relatively distinct patterns of association with environmental predictors, even in similar diseases (growth anomalies) found on different host genera (Acropora vs. Porites). As human densities and environmental degradation increase globally, the prevalence of coral diseases like PGAs could increase accordingly, halted only perhaps by declines in host density below thresholds required for disease establishment.
authors.affiliation: Hawaii Institute of Marine Biology, Kaneohe, Hawaii, United States of America.
authors.forename: Greta S
authors.initials: GS
authors.lastname: Aeby
authors.forename: Gareth J
authors.initials: GJ
authors.lastname: Williams
authors.forename: Erik C
authors.initials: EC
authors.lastname: Franklin
authors.forename: Jessica
authors.initials: J
authors.lastname: Haapkyla
authors.forename: C Drew
authors.initials: CD
authors.lastname: Harvell
authors.forename: Stephen
authors.initials: S
authors.lastname: Neale
authors.forename: Cathie A
authors.initials: CA
authors.lastname: Page
authors.forename: Laurie
authors.initials: L
authors.lastname: Raymundo
authors.forename: Bernardo
authors.initials: B
authors.lastname: Vargas-Ángel
authors.forename: Bette L
authors.initials: BL
authors.lastname: Willis
authors.forename: Thierry M
authors.initials: TM
authors.lastname: Work
authors.forename: Simon K
authors.initials: SK
authors.lastname: Davy
mesh_terms: D000820:Animal Diseases / Q000453:epidemiology*; D000818:Animals; D037421:Anthozoa / Q000145:classification / Q000254:growth & development*; D017753:Ecosystem; D004777:Environment; D006130:Growth Disorders / Q000453:epidemiology; D006802:Human Activities / Q000706:statistics & numerical data; D006801:Humans; D019156:Indian Ocean; D010140:Pacific Ocean; D011156:Population Density; D015995:Prevalence