HONOLULU -- Warning signs were posted Sunday after thousands of gallons of sewage spilled out of manholes in several areas across Oahu.

This weekend's heavy rains are being blamed for the overflows from Nuuanu to Kailua.

Fishermen cast their nets in Kaelepulu Stream at Kailua Beach, where fish are plentiful right after heavy rains.

"Usually, when there's heavy rains, they open the mouth of the river to relieve the water, and when the high tide comes in, the fish smell that fresh saltwater and they come out," fisherman Curtis Chung said.

But the heavy rains also caused three sewer manholes to overflow, including one at Keolu Drive and Hele Street.

More than 4,000 gallons of sewage spilled onto the streets and emptied into drainage systems and into Kaelepulu Stream.

"When the tide goes down in the brown water, you can see it coming back because the fresh water is going out," Chung said.

Warning signs in English and Japanese advised the public against fishing and swimming in the area. But that didn't stop kayakers. And fishermen said they didn't notice the signs, which were posted across the street and behind where the fishermen were casting.

Sewer manholes also overflowed at two locations in Nuuanu.

Rocks sat on a manhole on Luakini Street, where more than 2,300 gallons of sewer overflowed into Nuuanu Stream behind a residential area. Signs also were posted there.

Back at Kaelepulu Stream, experienced fisherman and novices were hitting the jackpot.

They caught piles of awa awa. One man caught a 5-pound Samoan crab. While some said they might eat the fish, others admitted they're concerned about the polluted water and won't eat their catch.

"I just do this for practice, (so) when I go out in the ocean, I've still got my skills," a fisherman named John said.

Others said they would sell it or give it away.

"So it's not bothering you at all?" reporter Jodi Leong asked Chung.

"No," he said, with a laugh. "But I wouldn't eat none of it."