Odyssey Marine Exploration, which recovered coins from the “Black Swan” shipwreck in 2007, continues to appeal a ruling that the 17 tons of treasure from the vessel belong to Spain.

Oral arguments in the case of Odyssey Marine Exploration v. Kingdom of Spain were held before a three-judge panel on May 24 in the United States Court of Appeals for the Eleventh Circuit, Atlanta.

The “Black Swan” is the name given to a major shipwreck discovered in international waters on the floor of the Atlantic Ocean off the coast of Portugal. It was found by Tampa, Fla., firm Odyssey Marine, which announced the discovery on May 18, 2007.

Artifacts recovered from the Black Swan included more than 500,000 silver coins weighing more than 17 tons, hundreds of gold coins, additional gold items and other artifacts. At the time Odyssey Marine believed that the recovery constituted the largest collection of coins ever excavated from a historical shipwreck site. Odyssey Marine’s initial press release stated that it was not prepared to disclose the possible identity of the shipwreck at the time.

Who owns the treasure?

For the duration of the case, Odyssey Marine has argued that a “finder’s keepers” rule should give it rights to the treasure. Spain has continued its argument that international treaties and maritime law obligate Odyssey Marine to return the treasure to Spain.

Various legal battles have occurred since the discovery, much of the dispute involving the classification of the Black Swan, which Spain contends is the Spanish naval vessel the Mercedes, a Spanish frigate that exploded in 1804. Spain never abandoned the sovereignty of the vessel and has argued that the warship should be given the same rights as American lost naval vessels.

Spain has called the warship a graveyard, arguing that U.S. courts do not have jurisdiction in the matter and that Spain’s courts should settle the argument. Attorneys for the U.S. Justice Department have supported returning the treasure to Spain, contending that Spain deserves protection for sunken warships.

Spain requested to give some of its allotted oral argument time to attorneys representing the United States, reasoning, “The issues presented in this case include the shared views of the United States and Spain on the interpretation and application of the Treaty of Friendship and General Relations between the United States and Spain, 33 Stat. 2105 (1903), and, in particular, its provisions requiring recognition of immunities for the sunken vessels of both nations.”

In on Dec. 22, 2009, U.S. District Judge Steven D. Merryday issued an order agreeing with the June 3, 2009, findings of a magistrate judge who expressed doubts that an American federal court has jurisdiction over the found property. Odyssey subsequently appealed to the Eleventh Circuit Court of Appeals.

Judge Merryday ruled that the recovered coins are to remain in Odyssey’s possession pending the decision by the Appeals court. He wrote, “The ineffable truth of this case is that the Mercedes is a naval vessel of Spain and that the wreck of this naval vessel, the vessel’s cargo, and any human remains are the natural and legal patrimony of Spain and are entitled in good conscience and in law to lay undisturbed in perpetuity absent the consent of Spain and despite any man’s aspiration to the contrary.”

Odyssey Marine responded to the ruling in a press release and in its subsequent appeal that even if the coins recovered were once part of the Mercedes, the ship is not entitled to the sovereign immunity enjoyed by warships on strictly military service as it was serving a commercial function when it sank.

Interpreting evidence

Much of the oral arguments on May 24 centered on interpreting contextual evidence found at the shipwreck that would indicate that it was a warship, such as the presence and location of cannons, firearm remnants and ammunition. If the ship is classified as a warship, Spain’s claim would be strengthened as maritime law protects warships sunk during times of battle from treasure seekers.

Yet, Odyssey Marine argues that the ship sailed during a time of peace, and that the ship carried commercial merchandise, citing as evidence that the ship’s gun decks were clogged with private merchant cargo. As such, the ship would not have been able to serve its function as a warship.

Peru has also requested rights to the wreckage, arguing that it was part of the Spanish empire when the ship sank. Attorneys for Peru have accused Spain of avoiding to directly address Peru’s claim, arguing, “Peru’s ownership claim has the exact historical basis as Spain’s because ‘Spanish’ ownership in 1804 subsumed Peruvian ownership.”

The Black Swan case received press attention earlier this year when U.S. diplomatic cables released by WikiLeaks showed that the U.S. government provided confidential customs documents prepared by Odyssey Marine concerning the coins. The cables described how U.S. ambassadors offered confidential customs documents to Spain, hoping to obtain assistance in the return of a stolen Impressionist painting to a U.S. citizen. The painting remains in a Spanish museum, which refuses to release the artwork.

The Black Swan was also the subject of a Discovery Channel Treasure Quest episode in 2009.

It may take several months for the three-judge panel to issue a ruling, and that ruling may continue to be challenged by Peru and descendants of the merchants who were sending cargo on the ship. ¦