Disease outbreaks substantially enhance greenhouse gas emissions from Asian seabass (Lates calcarifer) aquaculture pond

Abstract

Asian seabass (Lates calcarifer) is a globally important aquaculture species. Rising demand for food has driven the development of high-density and intensive farming systems. However, these practices have also heightened the risk of disease outbreaks, which now represent a major challenge for the aquaculture industry. Notably, little is known about greenhouse gas (GHG) flux dynamics during seabass culture, particularly under disease outbreak conditions. In this study, we monitored a traditional earthen pond, measuring CO2, CH4, and N2O fluxes with environmental parameters. A giant seaperch iridovirus (GSIV) outbreak occurred between June and July, causing mortality of at least 30 % of the fish stock. Our analysis showed that CO2 emissions during the outbreak increased dramatically, reaching 15 times the levels observed under normal conditions (45.33 f 28.05 g m- 2 day- 1), whereas CH4 (10.35 f 8.30 mg m- 2 day- 1) and N2O (3.23 f 0.74 mg m- 2 day- 1) fluxes did not show significant changes. In the later culture stages, however, elevated concentrations of CH4 (46.56 f 33.43 nM) and N2O (233.73 f 126.54 nM) accumulated in the water, and under strong wind conditions, pronounced flux peaks of CH4 (74.98 f 73.73 mg m- 2 day- 1) and N2O (27.02 f 34 mg m- 2 day- 1) were observed. Using the GWP100 values from the IPCC AR6 report, the average GHG flux across the culture period was estimated at 10.09 f 9.03 g CO2-eq m- 2 day- 1, confirming that seabass ponds acted as net sources of greenhouse gases. These findings highlight disease outbreaks as amplifiers of GHG emissions and stress that improved disease control is vital for both productivity and mitigation.