Abrupt ocean warming could lead to mass fish deaths, a study suggests. Studies of the ecological impacts of ocean warming have traditionally focused on the duration and maximum temperatures of warming events but not on the rate of warming. Amatzia Genin and colleagues examined the mass mortality of fish that occurred in the northern Red Sea following two rapid warming events in July 2017. During both events, temperatures rose by more than 3 °C in 2.5 days, although the maximum temperatures reached were well within the normal temperature range for the season. For 10 weeks following the initial warming event, hundreds of fish carcasses were collected along the coast near Eilat, Israel. Necropsies performed on moribund and freshly dead specimens revealed infection by Streptococcus iniae, a ubiquitous bacterial pathogen of fish, in nearly all cases. Piscivorous and benthic grazing species, such as groupers and parrotfish, were disproportionately represented among the carcasses, suggesting that the infection likely spread through consumption of infected fish and their carcasses. The authors reexamined two earlier documented mass fish kills, in Kuwait Bay in 2001 and western Australia in 2011, and found that both were immediately preceded by rapid warming spikes. The results suggest that the rapid onset of warming, regardless of the final temperature attained, might trigger widespread mortality of coral reef fish, according to the authors.
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Article #20-09748: "Rapid onsets of warming events trigger mass mortality of coral reef fish," by Amatzia Genin, Liraz Levy, Galit Sharon, Dionysios E. Raitsos, and Arik Diamant.
MEDIA CONTACT: Amatzia Genin, The Hebrew University of Jerusalem and the Interuniversity Institute for Marine Sciences, Eilat, ISRAEL; tel: +972-54-8820934; e-mail: a.genin@mail.huji.ac.il
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Proceedings of the National Academy of Sciences