Rowell will present the team's research at the Gulf of California conference held June 13-16 at the Westward Look Resort in Tucson, Ariz. Her presentation, "Isotopic Logs from the Sea of Cortez: Environmental and Life History Records From Totoaba and Gulf Corvina Otoliths " will be given at 4 p.m. on Monday, June 14, in Colorado River Delta Session. Her coauthors are Flessa and David Dettman, a research scientist in UA's department of geosciences.

The research was funded in part by the National Science Foundation, the Southern Arizona Environmental Management Society, the Chevron Research Fund and T&E, Inc.

Totoaba macdonaldi was the first commercially important fish in the northern Gulf of California. The fish can live 20-something years and grow to six feet in length. "San Felipe used to be just an ephemeral fishing village for totoaba," Rowell said. "They used to ship them overland to San Francisco and San Diego. It was the first time they tried to use refrigerated cars."

The commercial totoaba fishery crashed in 1975. Overfishing has been blamed for totoaba's decline. The fish was listed by the United States as federally endangered in 1979. The current size of the totoaba population is unknown.

Gulf corvina, Cynoscion othonopterus, are still fished commercially, although the American Fisheries Society, the professional society of fisheries biologists, has recently identified the species as "vulnerable," because of habitat changes in the fish's nursery area and heavy fishing pressure in fish's spawning site.

Estuaries, zones where fresh river water and salty ocean water mix to form brackish water, are known to be nursery areas for many species of marine life, including many fishes.

Both totoaba and gulf corvina spawn in the mouth of the Colorado, according to fishermen's reports. Rowell wondered whether otoliths from totoaba a
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8-Jun-2004