The International Seafood Sustainability Foundation (ISSF) has issued an updated snapshot of large-scale tuna purse seine fishing fleets report as of June 2019

The total number of large purse seine vessels, calculated based on data from the five tuna RFMOs, has dropped from 1871 in 2018 to 1843 today, mainly due to the removal from RFMO lists of vessels under 24m that are now inactive, according to the International Seafood Sustainability Foundation’s (ISSF) snapshot of large-scale tuna purse seine fishing fleets report as of June 2019.

According to ISSF, having an accurate estimate of active vessels is critical for managing tuna fishing capacity regionally as well as globally. Although purse seine vessels account for approximately 65% of the 4.9-million-tonne global tuna catch, several databases must be searched to count all authorised purse seine vessels.

To provide an annual best estimate – and to track capacity changes from year to year – ISSF analyses and aggregates information from the five tuna RFMOs and other sources.

97% of the large-scale tropical tuna purse seiners operating today have publicly available IMO numbers, while in 2011 that figure was 12%, according to ISSF

As ISSF’s report explains, these figures may underestimate the total fleet, because many small-scale purse seiners or purse seiners operating in only one exclusive economic zone (EEZ) do not have to be listed on RFMOs’ records of authorised fishing vessels.

ISSF concludes that in the tropical tuna large-scale purse seine (LSPS) fleet, fish hold volume (FHV) increased by 1% since 2018.

The report indicates that approximately 686 vessels (up 2%, from 673 last year) defined as large-scale purse seine (LSPS) vessels targeting tropical tuna species (skipjack, yellowfin, and bigeye), with a combined fishing capacity of over 860,000 cubic metres.

The increase is not all due to new vessel constructions, but also to the addition to RFMO lists of older vessels that were not listed in the past. These vessels may have been inactive for some time or participating in different fisheries, but this type of information is not readily available.

The report states that around 18% of the 686 large-scale vessels are authorised to fish in more than one RFMO jurisdiction and about 2% of these vessels changed flags in the last year.

Among the RFMOs, the Western and Central Pacific Fisheries Commission (WCPFC) still has the highest number of LSPS registrations (347), more than half of the total worldwide.

The majority of large-scale vessels (515) are registered on the ISSF ProActive Vessel Register (PVR); PVR-registered LSPS represent 75% in number and 83 percent in fish hold volume (FHV).

Nearly 100% of the purse seine vessels listed on PVR have IMO numbers. ISSF has long recommended in its RFMO advocacy positions and in Conservation Measures 4.1 and 4.2 that vessels obtain IMO numbers, identifiers that do not change even if the vessel ownership, national registration, or name changes. Unique vessel identifiers (UVIs) like IMO numbers are an important tool to combat illegal, unreported and unregulated (IUU) fishing.