NEW YORK (TheStreet) -- Somali pirates hijacked a ship Monday owned by Navios Maritime Partners (NMM - Get Report), the sister company of Navios Maritime Holdings (NM - Get Report).

The ship -- a 52,000 deadweight-ton handymax called the Navios Apollon, with a crew of 18 or 19 -- was carrying Mosaic ( MOS) phosphate fertilizer from Tampa, Fla., to India, according to reports. Pirates attacked the ship 200 nautical miles east of the Seychelles island chain in the Indian Ocean.

It was a busy day for Somalia's pirate gangs. First, they surrendered a container ship from Singapore, the Kota Wajar, but not before obtaining a reported $4 million in ransom.

Then, another vessel, a chemical tanker called the St. James Park and flying a U.K. flag was seized on Monday. Between 10 and 12 ships are now being held for ransom by Somali pirates in the Gulf of Aden and surrounding waters. Recently, the gangs have grown more daring in their attacks, targeting ships as far as a thousand miles offshore.

Navios, based in Greece, isn't the first publicly traded dry-bulk shipper to have a vessel successfully hijacked. In February, pirates seized DryShips' ( DRYS) Saldanha, a panamax-size coal carrier, which the company has since retrieved, presumably by paying a ransom. DryShips has refused to comment on the incident since.

Navios couldn't immediately be reached for comment.

--Written by Scott Eden in New York

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Scott Eden has covered business -- both large and small -- for more than a decade. Prior to joining TheStreet.com, he worked as a features reporter for Dealmaker and Trader Monthly magazines. Before that, he wrote for the Chicago Reader, that city's weekly paper. Early in his career, he was a staff reporter at the Dow Jones News Service. His reporting has appeared in The Wall Street Journal, Men's Journal, the St. Petersburg (Fla.) Times, and the Believer magazine, among other publications. He's also the author of Touchdown Jesus (Simon & Schuster, 2005), a nonfiction book about Notre Dame football fans and the business and politics of big-time college sports. He has degrees from Notre Dame and Washington University in St. Louis.