At least 230 people have been confirmed dead and an estimated 365 remain missing as result of crossings gone wrong, often as a result of unscrupulous smugglers forcing the migrants overboard.
The number fleeing is twice as high as the previous period last year. Over two-thirds of the migrants are Somali, while the majority of the others are Ethiopian, UNHCR said.
Increasing numbers of Somalis are fleeing the Islamist insurgency in their country as violence has picked up in recent months.
Almost daily battles have blighted Somalia since Ethiopian troops invaded in 2006 to remove the Islamic Courts movement from power, and restore the Western-backed transitional government.
Islamist insurgents have since fought back, taking over the key port town of Kismayo and hammering Ethiopian, government and AU peacekeeping troops.
Civilians have borne the brunt of the fighting, with aid agencies now estimating almost 10,000 have died since the insurgency began in early 2007.
Over one million people have fled the conflict, 200,000 of them to neighbouring Kenya.
Somalia has been plagued by chaos and clan-based civil war since dictator Mohamed Siad Barre was toppled in 1991. dpa ml jbl
- Deutsche Presse Agentur
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