SDSU Marine Researcher Is a Man With a Porpoise : His Study Looks at Bottlenose Dolphin as Adapter, Wanderer, Surfer Extraordinaire

Outboard motor growling, a warm breeze whipping by, the small powerboat bounced across the springtime chop just outside the surf zone, heading up the North County coastline. R. H. Defran stood at the wheel, scanning the breakers for his target.

Suddenly, he throttled down. The white-hulled Boston Whaler slumped into the swells, slowing to a crawl. Defran had spotted something. As the craft eased closer, they came into focus--the shiny gray backs and dorsal fins of two dozen bottlenose dolphins lolling in a calm stretch of water off the rocky shores of south Carlsbad.

“Oh, yes,” Defran murmured. “We’ve got close to 25. Oh, yes.”

The San Diego State University scientist turned the wheel over to his assistant, graduate student Gina Shultz, and pulled out a camera with a bazooka-like telephoto lens. Passive before, the dolphins now seemed to take their cue.

As Defran fired off film, a solitary dolphin flipped out of the water, its underbelly glistening in the sun. Others darted beneath the boat, riding the swell that was cresting off the bow. An especially adventurous pair dived into a gnarly shoreline breaker, skimming down the face, then popping out the back with an elemental grace.

“You see them surfing!” Defran yelped with primal glee. “He was right at the peak! You could see him like a gray shadow, right in the middle of that wave!”

Such excursions are a semimonthly ritual for Defran, who takes to the sea to collect data for an ongoing research project aimed at determining behavioral characteristics and the size and range of the bottlenose population plying the waters off Southern California.

So far, Defran’s project, conducted under the auspices of the SDSU Center for Marine Studies, has prompted as many questions about the dolphin as it has provided answers. Though the playful marine mammal may seem as familiar as Flipper, its habits in the wild remain something of a puzzle.

While the cadre of marine biologists

studying the species along the Atlantic and Gulf coasts have found the dolphin to be something of a homebody, sticking relatively close to a defined territory, Defran has determined that its Pacific Coast cousins are a more nomadic breed. Some charge up and down the shoreline from Santa Barbara as far south as Ensenada. Others may travel even farther.

Population Thriving

Moreover, Defran suggests after more than four years of study that the dolphins along the Southern California coast seem to be “thriving,” even as some biologists warn that increasing levels of pollutants and other interference from man threaten the fragile habitat of the bottlenose as never before.

“These guys are the ultimate in flexibility,” Defran said. “People draw parallels to coyotes in terms of their ability to be near human populations and adapt to them. We see dolphins out there with jet skiers, lobster fishermen, surfboarders--and pollution. They’re out there through it all.”

During their forays into the near-shore waters of North County, Defran and his students have observed schools of dolphins ranging from just a few individuals up to a group of 90 sighted in February, 1985, a veritable dolphin convention that stretched along three miles of shoreline south of Torrey Pines State Park.

The SDSU team, working in conjunction with biologists from Orange County, has catalogued nearly 400 different bottlenose since the survey was launched in January, 1984. Defran estimates that 300 to 500 bottlenose are off the Southern California coast at any one time, frolicking as they typically do near the surf zone no more than 500 yards from shore.

Surveillance Missions

Aside from taking a nose count, the researchers have in recent months focused on providing a precise inventory of the daily habits and foibles of the friendly marine animal. An SDSU graduate student under Defran’s tutelage is conducting a series of surveillance missions, hunkering down with high-powered binoculars at various spots dotting the North County coast, every few minutes recording each jump and tail splash of the dolphins he spots.

“We’re studying dolphin societies,” Defran explained. “We’re interested in the structure of that society; we’re interested in the dynamics, the movements; we’re interested in the whole picture.”

A stout man with sea-blue eyes and a face framed by a thick, graying beard and hair, Defran took a roundabout route to his days with the dolphins. He arrived at SDSU in 1970, fresh out of graduate school and with a background in behavior modification, pointed toward research on a hot topic of the day: self-paced instruction for schoolchildren.

Along the way, the young researcher was snagged by Sea World to teach operative instruction principles to the park’s dolphin and killer whale trainers. In exchange, Defran was given research space and a pair of dolphins to work with.

Approached by Colleague

He began laboratory tests with the animals, conducting experiments on cetacean vision, echo-location techniques and hearing. By 1978, that research had given way to new work, this time observing the social structure and behavior of bottlenose dolphins and other marine mammals in captivity.

In 1983, Defran was approached by another San Diego-based researcher, Larry Hansen, who was investigating the bottlenose along the county coastline. Hansen asked his colleague if he would like to assume control of the project. Defran jumped at the chance.

From the beginning, however, the research has been conducted on a shoestring budget. While Defran dreams of one day receiving sufficient aid to begin outfitting dolphins with radio tags to monitor their movements around-the-clock, his current operation is far more humble.

The group’s boat, a 17-foot fiberglass-hulled craft well suited for work near shore, is provided by the university’s Center for Marine Studies. A 400-millimeter lens and other camera gear are on loan from the National Marine Fisheries Service. Defran pays for the film and developing out of his own wallet.

Own Set of Fin Nicks

Despite such Draconian restraints, he and his cohorts have managed to compile an impressive log of data. Most of the work has been conducted in the principal study area between the Scripps Pier in La Jolla and the Encina power plant in Carlsbad, but Defran has made numerous jaunts in Santa Barbara waters as well as off the coast of Ensenada.

Much like a human is identified by its fingerprints, dolphins can be identified by the distinguishing nicks and cuts on the trailing edge of their dorsal fins. The nicks, caused by what Defran describes as “roughhouse play,” are nearly always unique to a particular animal.

After Defran clicks off photographs with his Nikon, a light-projection board is used back on campus to make tracings of each fin from the negative. Although the technique is not unique, the SDSU researchers have developed a new method to establish a ratio between various nicks on the fin. The coordinates are fed into a computer for easy and quick cross-referencing with future dolphin sightings.

“I think that type of work is valuable,” said Peter Boveng, an operations research analyst with the National Marine Fisheries Service in La Jolla. “In particular, the information they get on the movements of individuals has real implications for future management.”

Though such identification methods have helped the researchers begin to fix the size and range of the local dolphin population, questions remain. Perhaps most perplexing to Defran and his colleagues is the riddle of why these dolphins move up and down the coast, apparently at random.

Many marine mammals, such as gray whales, follow fixed migratory routes, but dolphins along the Southern California coast tend to travel north and south in no readily discernible pattern, Defran said.

The pursuit of fish and other prey might be one explanation, but a perplexing phenomenon shrouds that hypothesis. On several occasions, the researchers have seen two distinct schools of dolphins traveling toward one another. The groups mix, but then break apart again, each moving away from the other, as if going fishing is the furthest thing from their minds.

“It’s like you have two caravans passing in the desert,” Defran said.

He suggested that the Pacific Coast bottlenose dolphin may be prone to wandering because of the open nature of the shoreline, with its few bays and eddies for protection.

Indeed, the prime variable “is the ecology, the environment, and how it puts pressures on them to develop behavior patterns that are different” from aquatic peers along other coasts, Defran said. Just as a La Jollan differs from a resident of Appalachia, a Pacific Coast dolphin differs from its Atlantic or Gulf coast brethren.

Scientists believe the species typically sticks close to the shoreline, but bottlenose populations also exist near Santa Catalina and the Channel Islands off Santa Barbara. Questions remain about whether the near-shore and offshore colonies mix, but Defran hopes to provide answers in the coming months by conducting identification missions along the islands.

In recent years, a furor has brewed over tuna fishermen who catch dolphins in their nets in the tropical Eastern Pacific. According to officials at the National Marine Fisheries Service, the species involved are the spotted dolphin and spinner dolphin, which frequent waters deeper than that of the bottlenose.

However, a potential threat looms for the bottlenose: near-shore pollution. Biologists have found higher concentrations of DDT and heavy metals in dolphins off Southern California than in any other marine mammal.

Many Young Sighted

Nonetheless, Defran said his research has indicated that, if anything, the bottlenose population is flourishing. Nearly one out of 10 dolphins sighted is a youngster, suggesting that the reproductive cycle of the species is healthy, he said.

But Defran offers a note of caution. Though bottlenose dolphins may be able to carry a higher load of pollutants, “it is not to say there isn’t a time bomb ticking” that could ultimately have a profound impact on the species.

“The dolphin is an index of the robustness of the marine ecology,” he said. “For the most part, they’re the top dogs. So if these guys are gone, there’s some bad things happening down below.”

Shifts in population can happen in a blink. Last summer, more than 250 dolphins washed up on beaches from New Jersey to Virginia, victims of a common ocean bacteria. Such environmental calamities buttress the resolve of Defran and other researchers to see ongoing population counts taken of the Pacific Coast bottlenose.

Guaranteed Show Stopper

The counts can also prove fruitful if future management of the dolphin is necessary. Should a commercial fishery develop that is attractive to the bottlenose, a definitive population figure would be needed to correctly set limits on the numbers of bottlenose that could be taken in fishermen’s nets.

On the behavioral front, the SDSU team is beginning to make headway. The bottlenose has carved a permanent niche as the guaranteed show stopper at marine amusement parks such as Sea World, but it has been subjected to little solid behavioral research in the wild.

Much of the data being gathered by Defran and his assistants has yet to be analyzed, but several characteristics of the dolphin are already common knowledge to anyone who has watched the animals cavorting in the sun-dappled waters off San Diego County.

Dolphins seem to spend a great deal of time in play, surfing atop waves or dragging blooms of kelp with their dorsal fin “like a chimp might drag around a burlap sack,” Defran said.

Surfing for Play

“They surf at length. You’ll see them waiting for a big set to come. They’re just like the guys out there on the boards, spending time in the ‘green room.’ And they do it a lot.”

Like humans, the animals nurse their young for prolonged periods, and often develop long-term relationships. Defran said his studies have identified several dolphins that were sighted together on different occasions several years apart.

The dolphins’ adaptability is remarkable. When the warm ocean current known as El Nino shifted dramatically northward in 1983, many species of warm-water fish moved with it. Defran believes the bottlenose dolphin mirrored that shift.

Since El Nino has subsided, however, many of the dolphins have continued to thrive in waters far north of their traditional haunts, he said. The dolphin once inhabited coastal waters only as far up the coast as Los Angeles, but its northern limits are now believed to be near Santa Barbara.

“It’s like the sailors who came to San Diego during the war. Some of them came and never left,” said Defran, who will present a paper on the topic during a conference in La Jolla later this month. “These animals may be exploiting this new niche. They found they liked it and are staying.”

BOTTLENOSE DOLPHIN: A profile

Tursiops truncatus

Warm-blooded mammal. Small, toothed whale.

Length: Up to 12 feet.

Weight: As much as 500 pounds.

Coloring: Gray with lighter belly.

Location: All oceans. Prefers warm or tropical waters. Ranges from the equator as far north as Japan and Norway, and as far south as Argentina, New Zealand and South Africa. Most hug the shoreline, but some bottlenose have been seen in deeper waters.

Diet: Fish and squid. Termed “smorgasbord” eaters.

Natural enemy: Sharks.

Of note: Dolphins rank among the most intelligent of animals, with chimpanzees and dogs. Most of the performing dolphins are bottlenose caught in the Gulf of Mexico, where they can be herded into shallow bays and captured. They have a highly developed sense of hearing, good vision, a keen sense of touch and a natural sonar system. They have no sense of smell and little, if any, sense of taste. Young are nursed for about 16 months. Dolphins can live 25 to 35 years in the wild.