Mystery of Bay Turtles Unsolved : SDSU Scholar Spent 10 Years Seeking the Key to Secret

The murky waters boiled like a witch’s caldron on the cold December day when Margie Stinson discovered the well-kept secret of South Bay.

It awed her and excited her. And, in the decade since she first glimpsed the cold malevolent eyes, gaping jaws and awesome carapaces of those giant green sea turtles, the Vista woman has dedicated her life to uncovering the mysteries of the prehistoric reptiles.

Her single-minded effort has earned her a master’s degree in biology at San Diego State University but has not yielded a single satisfactory answer to the strange behavior of the behemoths that visit San Diego Bay each winter and depart each spring.

Stinson, who may know more about green sea turtles than anyone living or dead, was a graduate student in search of a thesis in 1976 when her friend and employer, Ed McEwen, skipper of the sportfishing boat Pacific Queen, first told her of the existence of a clan of giant sea turtles that arrived each year in late October or early November and spent the winter and early spring in a narrow rocky channel where San Diego Gas & Electric Co. discharges coolant water used in its South Bay power plant.

McEwen violated an unwritten vow of silence about the turtles that has kept them from harm for the past 25 years or more. Hundreds of insiders who live or work in South Bay, plus a few “outsiders” like the late Carl Hubbs, renowned Scripps Insituation of Oceanography scientist, have guarded the privacy of the green sea turtles from those who would disturb them. Stinson didn’t believe McEwen’s tale of giant sea turtles in San Diego Bay. She thought he was pulling her leg. So she went down there to see for herself.

“Later that year (1976), during one very rainy, wind-swept December afternoon, crouched with binoculars along the bay’s southeasternmost shore, I saw for myself,” she wrote in the introduction to her 578-page master’s thesis.

“As wind whipped across the water, binoculars could not be focused fast enough to catch more than a glimpse of these giants surfacing for air. Surfacing with each rising turtle were questions concerning their biology in this bay, their existence in these northern waters,” Stinson wrote.

In the months and years that followed, Stinson spent lonely hours observing the wayward turtle band. Why, when the rest of their breed were hundreds of miles south, wintering in the 80-degree waters off southern Mexico and Central America, was this band of 25 to 30 green sea turtles braving the chilly winter waters of San Diego Bay? Why did they return every year to this narrow, inhospitable inlet in South Bay? Why, in late April or early May, just when the spring water temperatures were warming to the tropical levels in which sea turtles thrive, did they silently and as a group leave their South Bay habitat? And where, oh where, did they go?

One clue, which at first promised to answer some of these basic questions, was the water temperature in the SDG&E; discharge channel. Because the coolant water pouring into the bay from four large pipes at a rate of more than 400,000 gallons a minute was 10 to 15 degrees warmer than the bay waters, Stinson said, perhaps the South Bay turtles had cleverly discovered a tropical spa in an otherwise wintry world. Like Canadian tourists, “snow birds” who head for Southern California to escape the ice and snow of their hometowns each winter, the sea turtles pop into San Diego Bay and head for SDG&E;’s warm water inlet to cavort in the roiling waters of the discharge pipes until spring.

But, if the warm waters of the SDG&E; inlet drew them, then why did they leave just when the bay and ocean waters warmed to near-tropical levels? And, what were they doing in these northern waters in winter, year after year, when any sensible green sea turtle wouldn’t be seen dead north of the southern tip of the Baja California peninsula?

And, why, if they summered down south with the rest of their species, did they make the same mistake each year and go north for the winter? The more answers she sought, the more questions she came up with.

After years of observing the South Bay clan, of getting to know them personally enough to attach names such as Red Lady (a 380-pound loner) and Wrinkle Butt (a 312-pound female with a deformed carapace and a sagging rear end), of failing and finally succeeding in capturing a few, of attaching telemetric monitoring devices to some and forcing others to swallow lipstick-sized temperature monitors, of tracking their movements until fatigue forced her to shore, Stinson can only marvel at these hardy reptiles. She can’t explain their behavior.

Perhaps they just happened to be passing by the entrance to the bay each late October and, remembering their exclusive warm-water Jacuzzi, decided to stop off instead of making a tiring journey south. Perhaps they live here year around, heading out to sea as the spring sun warms the ocean waters. But, if so, where do they breed? There are no suitable breeding grounds within hundreds of miles of San Diego Bay.

When she managed, after two years of trial and failure, to attach monitoring devices to six captured turtles in 1979, she answered one question. The green sea turtles do not spend the summer in San Diego Bay. There were no signals from the telemetric devices between May and October. There were no sightings of turtles in the bay.

Stinson remembers the many failures trying to capture one of the turtles.

She had tried to capture the reptiles using tuna fishermen’s nets strung across the width of the channel only to find that the force of the water gushing from the SDG&E; discharge pipes flung the nets about wildly and entangled members of the Navy’s SEAL team who had volunteered for underwater turtle-catching duties.

“I was sure that I had caused those poor men to drown,” she said of the frantic moments before the nets and divers were retrieved.

Later, lighter-weight gill nets were tried but “those turtles cut right through them like they were butter,” she recalled. “Finally one summer we got smart and went down and watched how the Mexicans caught turtles. Then we did the same.”

The keys were different netting and using the tidal flow. It was about dawn on Jan. 27, 1979, when the first green sea turtle was captured.

“We’d had the nets out for two days and nothing,” Stinson said. “There was a gale blowing from the south, so strong that we couldn’t keep the tents up. It was the crack of dawn when we spotted this flipper waving on the surface of the water. I suppose we could have just reached out and pulled it in but about five of us jumped in, up to our necks in the water, to get that turtle.”

As the catch was brought ashore by the soggy crew, the sun rose over snow-covered mountains to the east, a moment Stinson will never forget. “It seemed like the most exciting moment of my life,” she said.

The turtle was hardly a prize catch. It was a 30.5-pound juvenile, too young to determine its sex, nicknamed Peanut. Within hours, Stinson and her volunteers had captured three others, all males, weighing 184, 190 and 220 pounds. Despite their size and appearance the turtles “were extremely docile,” and quite cooperative despite the indignities that Stinson imposed upon them in compiling her scientific data and attaching monitoring devices.

That, too, was a trial and error experience. The first monitors proved faulty and the first method of attaching them--Super Glue--proved unsatisfactory. The glue dissolved in the salty water and left the monitors buried in the muddy bay bottom. Again the Navy came to Stinson’s rescue, this time using sophisticated electronic equipment to locate the missing monitors. Redesigned devices later were attached by drilling holes in the turtles’ tough carapaces and securing the monitors with plastic thongs.

Stinson learned to sail a skiff through the South Bay shallows so that she could follow the reptiles through their daily paces, noting their routes and routines, speculating on why they often surfaced in groups--a practice of air-breathing fish to confuse predators but hardly a necessary protective maneuver for the huge reptiles whose only major predator is man.

Five 24-hour vigils devoted to Red Lady, the largest female, earned several pages in Stinson’s thesis and led her to suggest that other biologists were in error when they postulated that sea turtles’ feeding and activity periods were daylight pursuits. Red Lady was a nocturnal diner who, with others in the band, spent her days in aimless ease, hanging around in the temperate waters of the power plant’s discharge waters.

Stinson also turned to local libraries to track her reptile prey. Newspaper clippings of 1857 appeared to solve the mystery with the story of a whaling ship captain named Bogart who decided to earn his fortune by importing hundreds of green sea turtles from 350 miles south of San Diego to holding pens on what is now North Island Naval Air Station. The huge reptiles, meant to be sold to San Diego restaurants or shipped up to San Francisco for gourmets there, broke out of their pens and swam free in the bay.

Could the maverick band that wintered in South Bay today be the grandchildren and great-grandchildren of Capt. Bogart’s escapees? Carl Hubbs frowned on Stinson’s speculation, pointing out that if that were so, the turtles would certainly remain in San Diego Bay year around or, if they did leave, would have left in the winter months many years before the SDG&E; plant’s warm-water outfall was constructed in 1960.

Stinson agrees. Newspaper stories were plentiful until the turn of the century, telling of the problems the giant turtles caused for fishermen in San Diego Bay and False Bay (now Mission Bay) and of local catches of sea turtles up to 500 pounds. But the newspaper reports dwindled to nothing by 1910. Between 1910 and 1960, only one or two reports of turtle sightings in the bay were recorded. If today’s turtles are descendants of those imported sea turtles of the 1850s, where were they for those 50 years?

She expanded her turtle research south into Mexico and north as far as the Gulf of Alaska, discovering that, contrary to most scientific reports, sea turtles were not uncommon along the northern U.S. coastline and sightings were on record within five degrees of the Arctic Circle. The sightings, however, were mainly in the summer months when ocean temperatures were moderate, not in the October-to-April period when the South Bay turtles appeared.

Despite the cold, wet nights, the failures, frustration and fatigue, Stinson would do it all again. And she would recruit all her friends, her family, her SDSU colleagues and advisers, the Navy, the sportfishing captain and crew “and everybody I ever knew that owed me a favor.”

In fact, she admits, she might just start all over again, get her doctoral degree and this time enlist satellites and the lastest space-age technology in tracking her wrong-way turtle band. “But first I have to get the money for it.” She’s spent thousands of hours, 10 years of her life and, “easily, $10,000 of my own money” seeking answers to the riddles that the South Bay sea turtles pose.