Before-survey warmth slopes did not clearly exceed after-survey slopes in four coral samples in 2003-2019

We tested whether coral bleaching had a stronger link to sea temperature before a survey than after it. Four Atlantic and Pacific samples in 2003-2010 and 2011-2019 used 4,854 repeat-site monthly records. Joint models controlled site, year, month and depth. All four country-cluster, four-test intervals for the before-minus-after slope included zero. Differences were +19.10, -1.22, +2.33 and +2.22 bleaching percentage points per C. The later Pacific before-survey slope was positive, but its difference from the after-survey slope was uncertain. Same-site calendar-month controls, year clusters and a positive-bleaching outcome also gave no clear contrast. This is a test of time specificity, not evidence of equal slopes or a causal heat effect. Sea temperature persistence, coarse monthly exposure, missing surveys and limited error clusters restrict inference. We provide source hashes, derived survey and monthly panels, code, checks and a figure.

coral bleaching · observation bias · sea surface temperature · temporal specificity · regional replication · null result