“And given that the complete voiding of undigested matter in a great white’s stomach can take up to three days, but usually no longer, I believe it’s fair to assume the great white attacked the merfolk within seventy-two hours of getting hooked on the fishing line.”

“That’s an impressive deduction, Marty. Yet three days is still a heck of a long time. And great whites are fast swimmers.”

“Indeed they are. But as you most certainly know, they have particular and predictable swimming habits. They will often spend months in one hunting ground before traveling hundreds if not thousands of miles through open ocean to reach another. Did you happen to measure the lipid stores in the great white’s liver during the necropsy?”

She nodded. “They were nearly full.”

“Well, there you go!” he said triumphantly. “Lipids fuel a great white’s migratory swim, which mean it wasn’t migrating when it was hooked but rather foraging in a hunting ground somewhere off the coast. Consequently, it wouldn’t have traveled very far at all during the seventy-two hours in question. How many fishing charter operators do you think there are along the coast here?”

“Hundreds, most likely,” she told him. “There are at least a dozen in Mirissa alone. However, I think I can save you a lot of time.” She paused a beat. “I know where the shark was hooked.”

Chapter 12

MARTY

“It was tagged!” Marty exclaimed, repeating what Elsa had just told him. It was the second-best news he’d received that day, and he couldn’t believe his luck. Over the last two years, he’d become accustomed to disappointment and setbacks in his search for merfolk. That the stars were finally aligning for him seemed too good to be true.

Elsa said, “My colleagues at SBMC tagged it. We routinely tag several species of sharks to identify their migratory patterns, seasonal feeding movements, and daily habits.”

“Was it an acoustic or SPOT tag?” he asked eagerly. Acoustic tags employ a basic transmitter-receiver technology, so a tagged shark has to come within range of an underwater receiver for its ID code to be recorded. SPOT tags, however, are the latest in tagging technology. They employ a much more powerful transmitter that communicates with a network of satellites each time the wet/dry sensor on the tag senses that the shark’s fin has broken the surface of the water, allowing the shark to be tracked actively, and much more precisely, over broad geographical areas.

Elsa said, “Since 2018 we’ve used SPOT tags exclusively.”

“Excellent!” Marty’s mind raced. “Your data—how would I go about viewing it? If it’s not too late, or too much trouble, I would happily come to your office…”

She was shaking her head. “Not necessary. It’s all uploaded on the web. May I use this computer?”

“Absolutely.”

Elsa sat in the seat Pip had vacated. As her hands darted across the keyboard, she said, “The young girl who showed you to the SBMC shed earlier has a PhD in information technology from Colombo University. She’s now overhauling the digital side of our tracking program. She’s also working on a very nifty app that will allow everyday people to upload photos of shark sightings along our beaches. The goal is to crowdsource critical data points to help facilitate the peaceful coexistence between humans and sharks.”