The four tropical-tuna RFMOs — the Inter-American Tropical Tuna Commission (IATTC), International Commission for the Conservation of Atlantic Tunas (ICCAT), Indian Ocean Tuna Commission (IOTC), and Western and Central Pacific Fisheries Commission (WCPFC) — prohibit purse seiners, and other vessels under certain conditions, from transshipping at sea. But at-sea transshipment overall has increased in recent years.
