Commercial tuna fisheries are among the most valuable fisheries on Earth, and with sales valued at more than US$40 billion a year, they play a vital role in coastal economies.1 Transshipment – the transfer of marine products from fishing vessels to carrier (i.e., transport) vessels at sea or in port – has emerged as a way to efficiently move fish to processing plants and markets.2
However, because of a lack of research, relatively little is known about the global scale and value of transshipment, leaving many people concerned that this activity could be an avenue for illegal, unreported, and unregulated fishing, the entry of illegal products into the marketplace, and other transnational crimes, especially in areas of the ocean where effective monitoring and controls are lacking.
To begin illuminating the business of transshipment, The Pew Charitable Trusts commissioned a first-of-its-kind comprehensive analysis by Poseidon Aquatic Resource Management Ltd. This research examined fishing industry data from 2012 to 2018 to estimate the volume of fish managed by the world’s five tuna regional fisheries management organizations (RFMOs) that was transshipped as well as the value of the transshipped quantities of tuna species during that span.3
The data shows that transshipment plays a significant role in the fishing industry worldwide. Poseidon estimates that in 2018 – the latest pre-pandemic year for which data is available – RFMO-managed fleets transshipped about 1.4 million metric tons of tuna, worth US$10.4 billion dollars at the final point of sale, as well as roughly 200,000 metric tons of other species.4
This chartbook documents the findings of the Poseidon research, including detailed information on the volume of transshipped fish reported to all tuna RFMOs in 2018, as well as economic data for six highly valuable tuna species: skipjack (Katsuwonus pelamis), albacore (Thunnus alalunga), bigeye (T. obesus), yellowfin (T. albacares), Atlantic bluefin (T. thynnus), and southern bluefin (T. maccoyii). It also outlines a set of recommendations, compiled by Pew experts, to help RFMOs improve the oversight of transshipment and with it, the overall health of global fisheries.
The type of fishing gear used influences the scale of transshipment of various species. Tuna vessels fall into two main gear categories: purse seine and longline.
Purse seine vessels, which land most tunas worldwide, use large nets to encircle schools of fish. Because this gear is efficient at catching large volumes, it is the dominant method used for skipjack and yellowfin destined for canneries.
Longline vessels drag elaborate fishing lines made of up main lines that can be miles long and smaller branch lines that together carry thousands of baited hooks. Longlines are the second-most common type of gear (after purse seine), are used to catch several species of tuna, and mainly supply high-quality fresh or frozen fish to the market. Yellowfin, bigeye, and bluefin tunas for sashimi caught with longlines and handlines command higher prices per metric ton than tuna for canning that is caught by purse seine vessels.
The tuna RFMOs oversee substantial transshipment of commercial tunas as well as billfishes, sharks, other tunas, and other unidentified species.5 In 2018, skipjack and yellowfin were the most transshipped tuna species, making up nearly 75% (more than 1.2 million metric tons) of all transshipped catch reported to the tuna RFMOs. Tuna fleets also reported transshipping some species that are not managed by tuna RFMOs. For example, more than 8,000 metric tons of oilfish, primarily caught by longline vessels in the Indian Ocean, was transshipped in 2018.
The Pacific Ocean is home to the majority of transshipment of tuna and tuna-like species—69% of the global total—with most of this activity occurring in areas managed by the Western and Central Pacific Fisheries Commission (WCPFC), including in the geographic overlap between WCPFC and the Inter-American Tropical Tuna Commission (IATTC).
The significant tuna catch in the Pacific and the overall size of the area explain the large volume of fish transshipped in the region.
Most transshipment occurs in port between carrier vessels and purse seine vessels, which mainly catch tuna that end up in cans and which accounted for 84% of all transshipped catch in 2018. Longline vessels primarily transship at sea, allowing high-value fresh catch, such as bigeye tuna, to reach the dock as quickly as possible.
Although many marine products are transshipped, six highly valuable tuna species drive the transshipment practices of tuna fleets around the world.6 In 2018, transshipment of these species accounted for more than 1.4 million metric tons of tuna, or about 27% of the year’s total tuna catch, with most of that transshipped in port.
In 2018, vessels transshipped more than US$9 billion worth of tropical tunas, skipjack, yellowfin, and bigeye. Of those, skipjack and yellowfin, which are primarily caught by purse seine vessels, made up the most significant portion. Although caught primarily with longlines and with less frequency, bigeye tuna requiring prompt delivery to high-end sushi and sashimi markets also accounted for a large share of the transshipped value worldwide.
Table 1
End value and volume by gear type in metric tons, 2018
| Gear | 2018 volume by gear (metric tons) | 2018 transshipped end value per metric ton (end value/volume) |
|---|---|---|
| Purse seine | 1.23 million | US$6,100 |
| Longline | 195,000 | US$14,600 |
Source: Graeme Macfadyen, Transshipment Estimations, 2022
Although tuna caught by purse seine vessels makes up the bulk of the transshipped volume, longline-caught tunas, primarily bigeye, bluefin, and albacore, are the most valuable per ton, mainly because of the higher prices that consumers pay for tuna sushi, sashimi, and loins. These high-value species drive the at-sea transshipment industry, as fishers aim to bring these products to seafood markets as quickly as possible.
Transshipment serves an important role in the seafood supply chain, particularly for valuable tuna fisheries. More than 27% – US$10.4 billion’s worth – of global tuna catch is transshipped each year. And although many RFMOs have already begun to more closely monitor and manage transshipment, wider adoption of the United Nations Food and Agriculture Organization’s (FAO’s) Voluntary Guidelines for Transshipment, which include reporting, monitoring, and information-sharing, can guarantee more comprehensive oversight.8 To ensure that these transfers are legal and sustainable, fisheries managers and government officials should implement the guidelines and improve individual oversight in three key areas:
Whether at sea or in port, transshipment is a major part of the global tuna fishing industry. Strong oversight and port inspections are integral to keep illegal seafood out of global supply chains, particularly because nearly a third of high-value tuna is transshipped. Decision makers at RFMOs should embrace Pew’s recommendations and the FAO’s voluntary guidelines to improve the process and strengthen rules on the high seas and in port. Through intergovernmental and regional coordination, countries and RFMOs can continue to develop and implement regulations to ensure that all transshipment of catch is legal and verifiable, reduce opportunities for illegal products to reach the market, and maintain a healthy, transparent marine economy.