4 Mud flats are gulf's nursery

On islands north of San Felipe, shells are exposed as far as the eye can see. Erosion by gulf waters and lack of Colorado River sediment lay them bare.

For millions of years, the Colorado's surging spring snowmelt carved the Grand Canyon and countless other chasms. The river then transported 70 percent of that sediment hundreds of miles to the delta, where it fanned out in the northern Gulf of California.

Today, tides that vary as much as 25 feet in a day expose the delta's innards in mile-wide mud flats that are rippled with hallucinatory patterns from the receding and advancing sea. The spongy, chocolate-colored mud is literally crawling with snails, crabs and worms.

These invertebrate species near the bottom of the area's food chain nourish fish, stingrays and scores of bird species.

University of Arizona scientist Ed Glenn examined the records of shrimp fishermen from San Felipe, on the Baja California Peninsula, and concluded that the year following floods, their harvest doubled or tripled. Catches of corvina, once thought to be "fished out," rebounded tenfold after the delta got more water.

End of a River 'There's plenty of water. The thing is, we abuse it.' Lisa Force, director of Living Rivers click to view Photo Gallery

Some scientists suggest the Colorado supplies valuable nutrients to the upper gulf. Glenn, however, believes the river mainly helps marine life by discouraging predator fish from entering the Colorado's final stretch, which serves as a refuge for shrimp larvae and corvina fry.

Many biologists also think that healthier flows of fresh water to the gulf would have a cascading, positive effect on the gulf's other marine species, including the vaquita, an endangered porpoise.

San Felipe fishermen such as Arnaldo Espinoza Solano also thinks more river water would help.

"When there's more water in the river, it's more productive," said Solano, 35, who estimated unemployment in the area at 30 percent.

Born to the south in Sinaloa, Solano moved north to San Felipe six years ago to look for work. This summer, he'll be going north again, visiting a relative in Phoenix, working as a cook in a seafood restaurant and maybe staying in the United States.

"El agua es la vida," Solano said as he stared out at the sea.

Water is life.