Do reef fish catches fall after mass bleaching? A test with reported and reconstructed catch data in 51 countries and 95 exclusive economic zones, 1986–2024
Kitlesel ağarmalardan sonra resif balığı avı düşüyor mu? Bildirilen ve yeniden yapılandırılmış av verileriyle 51 ülke ve 95 münhasır ekonomik bölgede sınama, 1986–2024
This paper is being prepared for journal submission. The journal name and full text will be added after acceptance.
Abstract
The prediction that mass coral bleaching will cause reef fisheries to collapse is one of the main arguments in the debate on reef conservation; yet this prediction has not been tested at global scale with realised catch data. In this study the test is carried out with two independent catch data sets: national catches reported to FAO (51 countries, 1986–2024) and the reconstructed catches of the Sea Around Us initiative, which include subsistence and small-scale fisheries (95 exclusive economic zones, 1986–2019). Both data sets are matched with the heat-stress records of the regional stations of NOAA Coral Reef Watch, and the change in the catch of reef-associated fish over the ten years following heat-stress years is estimated by local projections with unit and year fixed effects. The two data sets give the same result: there is no decline in catch after heat stress. In reported catches the estimated change five years after severe heat stress is −4% (95% confidence interval −13% to 7%); in reconstructed catches it is 5% (−6% to 18%). In the reconstructed data, catches rose by 7% on average three to five years after moderate heat stress (permutation p = 0.01); however, catches of other species in the same zones also rose and the share of reef fish did not change, so the increase is not specific to reefs. Pre-event trends are zero in both data sets. The negative sign seen after repeated events in the reported data is not replicated in the reconstructed data. Over the five years following severe heat stress, the reconstructed data rule out a decline in reef fish catch of more than seven per cent and the reported data one of more than thirteen per cent. Catches continued to rise over the same period. The result indicates that the effect of bleaching on fisheries should be sought in catch composition, effort and at local scale rather than in total catch, and that catch volume cannot be used as an indicator of reef health.
Keywords
Coral bleaching; Degree heating week; Reef fisheries; Reconstructed catch; Local projection; Statistical power
Open code and data
Loading code…