Estimated production, catch per unit effort, biological aspects of tuna, skipjack, and small tuna in North SumatraGussasta Levi Arnenda, Fathur Rochman, Arief Wujdi and Roy KurniawanE3S Web Conf., 322 (2021) 03003DOI: https://doi.org/10.1051/e3sconf/202132203003