OCEAN SPRINGS — Little is known about whale sharks or why they come to the northern part of the Gulf by the hundreds in June and July, within 30 miles of the Coast.

But they do. And biologists from USM’s Gulf Coast Research Lab took what they do know about the giant, docile animals from the data they have collected and went whale shark hunting last week.

They were successful beyond their wildest expectations, placing satellite tags on three and measuring and documenting several more.

Shark biologist Eric Hoffmayer and research assistant Jennifer McKinney, along with a German videographer and a British photographer, set out on the expedition sponsored by a commercial red snapper fisherman who offered his 70-foot boat and crew.

“We had some idea of the hot spots in some regions” where the sharks were likely to be, Hoffmayer said. “But it was like trying to find a needle in a haystack.”

They started near the mouth of the Mississippi, because a chart of sightings in recent years flags that area of the Gulf, below Louisiana. They stayed along the Continental Shelf and used an aerial spotter — an airplane out of Ocean Springs Airport with marine biologist Gary Gray aboard — early in the search. By Day 3 their boat was sitting among whale shark.

The sharks had gathered near a weed line where fish were spawning, sending out millions of tiny eggs the sharks were feeding on. They also eat plankton, said researchers.

Researchers went into the water. Hoffmayer’s goal was to tag the giants with $4,000 transmitters that record data for nine months, then release from the fish, float to the surface and beam their findings to the lab via satellite.

Trying to swim alongside a whale shark, mid-body for the tagging, was an adventure all its own, he said. It’s the ocean’s largest fish.

Hoffmayer exhausted himself swimming as hard as he could, only to have them easily glide out of his reach.

But he was successful with three.

“They were feeding so they were a little slower and more tolerant of us, but some were still skittish,” he said.

With the new tags they hope to find out where they go the rest of the year, whether they travel together and how they know when to show up for an egg-feeding event.

Hoffmayer is also analyzing the fish eggs to find out what breeds might attract the sharks.

“This is just the beginning,” he said. “We’re just starting whale shark research.”

They’ve been collecting data since 2003 but urgently need boaters, pilots and oil-rig crews to report the locations of sharks they see to help the research. Last year was a banner year with 75 sightings reported.

“Every sighting gets us one step closer to understanding their movement patterns,” Hoffmayer said. “We’re really trying to figure out what these guys are doing. We’re starting to find out that there are more out there than we ever thought.”