This week the USA and Canada are seeking a ban on two fishing devices in the Pacific known as wire leaders and shark lines. This harmful fishing gear has had deadly impacts on shark populations and is imperiling oceanic whitetip sharks. Tuna longline vessels deploy lines with wire leaders that increases the likelihood a shark will be caught and maintained on the line, even if the boat is not fishing for sharks. Shark lines, with baited hooks set shallow where sharks are more likely to feed, increases the odds of killing sharks, as well as other animals such as seabirds and sea turtles.
Currently, rules established by agreement under the Western and Central Pacific Fisheries Commission (WCPFC) allows boats to use one type of gear or the other, but not both at the same time. However, this loophole allows fishing boats to have both aboard, and in proven cases, use them with impunity.
The Western and Central Pacific Fisheries Commission (WCPFC), which governs tuna fisheries is set to vote on this proposal at the annual meeting this week in the annual meeting in Vietnam.
Banning wire leaders and shark lines would reduce fishing mortality of oceanic whitetip sharks by 40.5% and silky sharks by 30.8%, research has found.
One of the most heavily fished sharks killed as bycatch on tuna fleets and targeted for their fins, oceanic whitetip sharks are critically endangered and on the brink of extinction. A recent scientific analysis by WCPFC determined that the Pacific population of oceanic whitetips, a critically endangered species, had plummeted by around 95%. In 2011 WCOFC declared a ban on intentionally catching oceanic whitetip sharks, or if accidentally caught, keeping possession of this species, yet oceanic whitetip shark populations are still in decline.
The authors conclude that at the current levels of fishing, oceanic whitetip sharks will go extinct in Pacific.
This harmful gear also catches blue sharks by the millions, and other species like internationally protected silky sharks,
Sharks are often caught as bycatch, especially in tuna longline fisheries. In some cases, over 50% of catch may be untargeted sharks. Unable to break free, sharks can suffocate on the wire lines. In the case of monofilament leaders, the shark can bite or abrade the leader and swim free. Wire leaders retain the shark however, causing death by suffocation.
Many fisheries also target sharks intentionally, harvesting them for their fins and meat, and in some cases for their skin, livers and carcasses for fertilizer. Using wire leaders and shark lines, these fishing vessels are minimally inspected, observed or regulated. Commercial fisheries on the high seas are governed by multilateral bodies that oversee international fishing grounds under the UN- known as Regional Fisheries Management Organizations (RFMOS). The Western and Central Pacific Fisheries Commission (WCPFC) was established by the Convention for the Conservation and Management of Highly Migratory Fish Stocks in the Western and Central Pacific Ocean. Covering approximately 33.9 million km² of ocean (13.1 million mi2), this region extends from Southeast Asian waters to north and east Australia, and further eastwards encompassing smaller island countries of the South Pacific from Fiji to French Polynesia. In the north central Pacific, the WCPFC governs fisheries international waters west of Hawaii.
In a move to protect the oceanic whitetip, the U.S. and Canada have asked the Western and Central Pacific Fisheries Commission (WCPFC), which governs tuna fisheries in those waters, to prohibit the use of wire leaders and shark lines. Prohibiting this harmful gear will provide easier enforcement by officials and reduce the impacts on dwindling populations of sharks.
Sharks are in Deep Trouble
A study in the journal Nature determined that open ocean species of sharks have declined by an estimated 71% in the past half-century, with an estimated 70-100 million sharks killed per year.
A 2009 analysis of world fisheries estimated 10–26 million tons of fish are caught as illegal, unreported, and unregulated fishing (IUU) each year, equal to around 11–19 percent of the global reported catch, estimated to cost global economies between $10–23 billion per year. Millions of sharks are caught in IUU fishing, which includes shark finning, the practice of taking the shark only for the fins. To counter this, the UN and many nations have condemned this practice making it illegal to kill a shark solely for the fins. An additional measure, although not yet fully adopted in the Pacific, is to require landings of all shark bodies with their fins attached.
The fins from oceanic sharks are particularly coveted for the Asian delicacy shark fin soup. Oceanic whitetips in particular have suffered from bycatch on longlines and directed catch targeting their fins. In 2011 WCOFC declared a ban on intentionally catching oceanic whitetip sharks, or if accidentally caught, keeping possession of this species, yet oceanic whitetip shark populations are still in decline.
Big Business, Bad Practices
An investigation into the Chinese owned Dalian Ocean Fishing (DOF) by the journal Mongabay, revealed that many of DOF vessels routinely use both wire leaders and shark lines to target huge numbers of sharks in the Pacific and Atlantic Oceans. Through direct interview of crewmen, the investigation revealed that just five of the DOF longliners in their fleet killed an estimated 31,000 sharks in the western Pacific in 2019. According to the investigation by Mongabay, at least four of these boats, (and probably the fifth as well), were verified using wire leaders together with shark lines, in violation of both WCPFC and Chinese regulations,
According to publicly available catch data, a November 2022 report published by the NGO Oceana, found that 189,793 metric tons of blue shark (Prionace glauca) were caught and landed legally in 2019, summing up to more than 7 million individual sharks, worth an estimated $411 million.
Spain, the largest shark fishing nation in the Atlantic, also caught 3,222 metric tons of blue sharks and 52 metric tons of of tuna in WCPFC waters in 2019, the report adds. Taiwan caught 41,724 metric tons of blue shark and 44,760 metric tons of tuna in WCPFC waters in 2019, while Japan caught 20,641 metric of blue shark and 40,168 metric tons of tuna.
Reducing accidental catch and regulating shark fisheries is critical to protect endangered sharks in the Pacific. Other measures needed to protect sharks include increased enforcement, increasing onboard observers, and reducing catch limits.
Last year, a similar proposal to ban wire leaders and shark lines, submitted by the USA and supported by the Pacific Islands Forum Fisheries Agency (FFA), representing 17 member states, including Australia, New Zealand and many Pacific Island countries. Calling for additional study, Japan, Taiwan, China and the EU did not back last year’s proposal, and the proposal never made it to a vote. New evidence on the decline of oceanic whitetip sharks provides additional justification to this year’s proposal.
The USA has led the way towards reducing impacts on by being the first to ban wire leaders.
In 2020, the Hawaiian Longline association which representing the largest U.S. flagged longline fleet operating in the western and central Pacific, prohibited the use of wire leaders on its vessels. Earlier this year, the U.S. National Marine Fisheries Service also issued a ban on all US flagged longline vessels.
This year in March, China- the world’s largest fishing nation- followed suit, prohibiting its fleet from using shark lines and wire leaders. However, in the case of companies like DOF, these prohibitions are ignored.
In the Atlantic, the International Commission for the Conservation of Atlantic Tunas, agreed to develop a Fisheries Management Plan for sharks, an additional requirement urgently needed in the Pacific, and included in this year’s proposal for the Pacific. This year’s proposal would also require sharks to be freed with as little trailing gear as possible, which research shows will improve survivability of the sharks once release
Just last week, in a move to protect endangered sharks from the wildlife trade, members at the Convention of International Trade of Endangered Species Coalition of the Parties (CoP19), agreed to list over 90 species of endangered and threatened sharks, including blue sharks, under international agreement.
Additionally, the US is calling for the finalization and adoption of a comprehensive conservation and management plan for the Pacific, including the fins-naturally-attached policy and catch quotas for all sharks and rays, to prevent other species from following the tragic trajectory of the oceanic whitetip shark. The annual meeting of the WCPFC is taking place November 27- December 3 in Da Nang, Vietnam, and we are urging delegates of member states in attendance to stand up for sharks and rays that are harvested in the Pacific.
Banning wire leaders and shark lines would reduce fishing mortality of oceanic whitetips by 40.5%, and that of silky sharks (Carcharhinus falciformis), another threatened species, by 30.8%, according to research cited in the WCPFC proposal.