Shore-distance heat links gave no stable common bleaching pattern in four Atlantic and Pacific samples in 2003-2019

We tested whether distance from shore changed the heat link to coral bleaching. We used 5,336 repeated-site months from Reef Check in two oceans and two periods. Models controlled site, year, month and depth. Three primary interaction intervals included zero. The later Pacific interaction was +3.80 bleaching percentage points per four TSA degree-heating weeks per unit log10(1 + distance in km), with a four-test country-cluster interval of +0.31 to +7.29. This interval included zero with year clusters, ecological-region clusters, same-site calendar-month comparisons, or a heat-by-turbidity control. These results do not establish a stable common coastal buffer. Missing reports, selected visits, sparse high heat in the Atlantic and uncertain error dependence limit inference. Shore distance does not measure pollution, and bleaching does not measure coral death or species loss.

coral bleaching · heat stress · shore distance · observation bias · regional replication · fixed effects