Enjoy the darkness: Forsake partially nocturnal sets provides a good opportunity to improve profits and sustainability in the southern Brazil longline fishery.

Pelagic longline fishing globally raises concerns for adverse interactions with non-target species, prompting the need for sustainable practices and effective mitigation. Adherence to bycatch measures varies globally, driving efforts to find cost-effective alternatives sustaining target species catch while minimizing bycatch. Our study, based in a previous research in southwestern Atlantic Ocean, confirms that fully nocturnal sets (FNS) are more effective in capturing target species (e.g. swordfish, tunas) and reducing bycatch of mako shark and loggerhead turtle compared to partially nocturnal sets (PNS). Extending the analysis to warm and cold seasons, FNS consistently outperforms PNS. In terms of profitability, trips with more FNS are generally more profitable than those with more PNS. Adopting only FNS in pelagic longline fishing seems to be viable, efficient in capturing target species, minimize bycatch, and potentially increasing profits—a promising solution for sustainable and economically viable pelagic longline fishing in southern Brazil. • We compared catches between fully- and partially nocturnal sets (FNS or PNS). • FNS captured more target and less bycatch than PNS for both warm and cold seasons. • Trips focused solely on FNS have the potential to be more profitable compared to PNS. • Forsake trips with PNS may reduce bycatch without affecting fishing incomes. [ABSTRACT FROM AUTHOR]