Blue Shark near the Azores. 07/14/2012 © Robert Marc Lehmann / Greenpeace

It's a macabre case spanning continents. A European vessel crewed by under paid and ill-treated Indonesian fishermen turned up in the port of Suva this week. Meanwhile, an illegal shipment of sharks, shark fins and other fish from the vessel is seized in Spain – and the owners are reportedly in a deal with New Zealand company SeaDragon to supply shark livers to be rendered into a cure-all product that's questioned by science.

The ship in question, Artico, doesn't have a great reputation. It's there on the Greenpeace monsterboats list – a compilation of vessels from Europe that are decimating fish stocks around the world on an industrial scale. Although flagged to Portugal and owned by Pescarias Cayon & Garcia LDA, the ship actually operates on the opposite side of the world, deploying its massive longlines with thousands of baited hooks in international waters just beyond the 200-mile limit of New Zealand's Exclusive Economic Zone (EEZ). Longline fishing is indiscriminate at the best of times, but the shipment seized in Vigo, Spain, has now raised suspicion that sharks may not just be an unfortunate bycatch in the quest to catch tuna: It indicates they could actually be the target catch of this illicit operation. Of the 190 tons of fish, 59 tons were shark species including 4.5 tons of severed fins.

Shark finning is a practice that is driving shark species around the world into serious decline, with many sharks listed as threated species and subject to conservation efforts and trade restrictions. In an initiative led by Tokelau and Palau, shark fishing is banned altogether by at least ten Pacific Island nations and territories that have declared their EEZ's as shark sanctuaries. Shark fishing is allowed in New Zealand and international waters, but not shark finning, which is banned by New Zealand and the Western and Central Pacific Tuna Commission. Finning is even more tightly regulated by the European Union, and those laws apply to the Portuguese vessel – despite operating on the far side of the world – through what are known as 'flag state responsibilities' of the European nation.

Some shark species have seen such alarming population declines that they are listed under the Convention on the International Trade in Endangered Species (CITES), which last year added five more shark species to the list. One, the oceanic whitetip, is the subject of a special conservation agreement by the Western and Central Pacific Tuna Commission, which requires that any of these animals that are caught be released back into the ocean.

The shipment from Artico reportedly contains a mixture of shark species, along with detached fins. These pose further difficulties for identification and some may even come from additional sharks whose bodies were not retained onboard. These uncertainties are why international best practice is to require that sharks are landed with their fins naturally attached to the bodies.

All things considered, it is clear that the Artico shipment is likely in violation of multiple laws from various jurisdictions.

Now holed up in Fiji, Artico is one of those vessels that simply should not be fishing. The ship must be seized and fully inspected, and once all evidence is gathered, its owners brought to justice. Ships like this belong in the scrapyard, not fishing in the Pacific Ocean. Greenpeace will be considering the vessel for addition to its pirate fishing blacklist. We urge retailers and other companies not to trade with the owners of blacklisted fishing vessels.

And what of the New Zealand company, SeaDragon? Is shark oil the new snake oil? It represents itself online with every bit of clean, green and 100% pure imagery it can muster, as well as a bold list of health benefits that fish oil can "assist with" including cardiovascular health, brain health, immune support, joint health and (who doesn't want this?) "general health". Yet it's peddling a fishy product that's questioned by science. Even worse, it has supply contracts with the owners of a vessel accused of poor crew treatment, and now of illegal shark finning.

Anyone thinking of dosing up or smearing shark liver oil on their face for purported health benefits or radiant skin should really stop and think. Is the rendered liver of a shark, which may have been caught illegally by underpaid crew eating only fish bait and drinking water from a rusted tank, really necessary to your health and beauty regime?

Karli ThomasKarli Thomas is senior oceans campaigner with Greenpeace Aotearoa New Zealand. She has spent many months at sea in fishing grounds, from the Mediterranean Sea to the Pacific Ocean and as far south as Antarctic waters. Karli coordinates Greenpeace's pirate fishing blacklist and works on illegal, unreported and unregulated fishing.