Image caption Health officials blame the treacle spill for the deaths of "many marine animals"

A 1,400-tonne treacle spill off the coast of Hawaii has killed thousands of fish, prompting health officials to issue a shark warning to swimmers.

A leak was discovered in a pipeline used to load the syrup on to ships, creating a sugary brown slick in Honolulu's harbour and nearby lagoon.

Health officials say they have already removed hundreds of dead fish from the water and expect thousands more.

Signs on nearby beaches warned bathers to stay out of the water.

Sticky predicament

The high concentration of treacle, known in the US as molasses, would make it difficult for the fish to breathe, state health department spokeswoman Janice Okubo told the Associated Press news agency.

TV footage showed some fish sticking their mouths out of the water.

"While molasses is not harmful to the public directly, the substance is polluting the water, causing fish to die and could lead to an increase in predator species such as sharks, barracuda and eels," the state health department said in a statement.

Heath officials expect the spill to be visible for weeks until tides and currents flush it out of the area.

They are concerned about potential increased growth of algae from the refined sugar.

Treacle is made at a sugar plantation on the US island state.

The firm that ships the sticky product to the US west coast about once a week, the Matson Navigation Company, repaired the hole and the pipe stopped leaking on Tuesday morning, spokesman Jeff Hull said.

Hawaiian officials said they could fine Matson for violations of the Clean Water Act, but the immediate priority was public safety.

In a statement, Matson said it would ensure spills did not occur in the future.