Hard coral cover gave no clear common heat-response change in four Atlantic and Pacific samples in 2003-2019

We tested whether the link between surface heat stress and coral bleaching varied with hard coral cover. Four site, year and month models used 6,338 Reef Check surveys in the Atlantic and Pacific in 2003-2010 and 2011-2019. Interaction estimates were +7.27, -0.68, +1.17 and +0.43 bleaching points per four TSA degree-heating weeks per 10 points more cover. Only the early Pacific country-cluster interval was above zero after adjustment for four tests. That interval included zero after several planned record, weight and error checks. Neither Atlantic sample had high-heat surveys with at least 50% cover. The evidence did not establish a common interaction. Cover and bleaching were measured together, so this test cannot establish protection by cover. Missing surveys, community change, limited heat support and few clusters restrict inference. The package gives the survey panel, source hashes, code, all results, a figure and independent checks.

coral bleaching · hard coral cover · heat stress · interaction · observation bias · regional replication