Yemen's coastguard said Somali pirates seized the fishing boat and its nine crew members off Yemen's southern coast as it was heading to the Mukalla port, according to a statement from the Ministry of Interior's website.
The statement said the pirates took the hijacked ship out 130 nautical miles south of the Yemeni island of Socotra.
"(They) did not head to the Somali coast," the statement said, "meaning it is likely the pirates will use the boat to attack merchant ships passing by the Socotra archipelago."
International navies patrolling the Indian Ocean say that pirates have been widening their attack areas further out at sea by hijacking smaller vessels to use as motherships.
Hijacking offers a lucrative alternative for many in impoverished Somalia, which is battling an Islamist insurgency.
Heavily armed Somali pirates have stepped up attacks in recent months, making tens of millions of dollars in ransoms from seizing ships in the Indian Ocean and Gulf of Aden.
