Last Thursday, the longtime head of the Florida Sea Grant science program, Karl Havens, gave a speech at an Everglades conference and then had lunch with his boss, Jack Payne of the University of Florida's Institute of Food and Agricultural Science.

Payne said Mr. Havens was in high spirits, cracking jokes about his inability to park his rented pickup truck. He also showed off some photos he shot amid the flames of a controlled forest burn he'd passed on the way, even though it left him covered in soot.

The next day, after lunch with a colleague, Mr. Havens said he was suffering from heartburn and went home early. It wasn't heartburn. He died of a heart attack at age 61.

Mr. Havens, a Buffalo native who held a Ph.D. in biology from West Virginia University, led the Florida Sea Grant cooperative for 11 years, and also served as a professor in fisheries and aquatic science at the University of Florida. Florida Sea Grant is a university-based program that supports research, education and extension to conserve coastal resources and enhance economic opportunities along the state's coasts.

Whenever a major biological crisis came up in Florida — from toxic algae blooms to the BP oil spill to the rapid decline of the state's oyster industry — Mr. Havens was often in the middle of it, looking for explanations and solutions.

"Karl was my go-to guy for so many issues," Payne said Monday, noting that Havens had produced more than 160 peer-reviewed scientific papers.

"He's just a good scientist," Payne added, still using the present tense for his friend. "He stands up for what the data shows."

Julie Wraithmell, the executive director of Audubon Florida, tweeted Monday that Mr. Havens "was always a voice for scientific rigor as well as educating Floridians about our water issues & how they can help."

Sometimes that involved bucking what the politicians wanted, Payne said. For instance his task force on the causes of the Apalachicola oyster decline decided the problems were caused by drought, followed by two tropical depressions, followed by overfishing that was prompted by then-Gov. Rick Scott lifting oyster harvest limits in the wake of the storms, Payne said.

Those findings ran counter to the claims in a lawsuit that Scott had filed against Georgia, accusing that state of using too much water from the river that flows through Apalachicola, Payne said. Havens wound up being called to testify by Georgia.

"I know that didn't make the governor happy," Payne added.

And when toxic blue-green algae bloomed on Lake Okeechobee, Mr. Havens was quick to point out that due to budget cuts the state had dropped the ball on collecting water quality data on a regular basis.

"No one is out on the lake collecting water samples of the bloom," he told a Miami Herald reporter. "We're flying blind."

In addition to chairing the university's oil spill task force in the wake of the 2010 Deepwater Horizon disaster, he was also in charge of its blue-green algae task force and strongly advocated using aerial photography and Geographic Information Systems technology to pinpoint the locations of tens of thousands of commercial lobster traps displaced by Hurricane Irma.

Co-workers hailed his ability to talk about scientific topics in a way that made sense to non-scientists. They also talked about what an enthusiastic person he could be, and how he was eager to collaborate with other scientists rather than try to forge his own path.

Mr. Havens also was "just a fun guy to be around," recalled Kelly Samek, Florida Sea Grant's program leader in the national Sea Grant office. She said when the national program held its annual fish fry in Washington, D.C., Havens was there touting his "Florida Keys seafood dip."

"He was always such a booster for all that Florida could be," Samek said.

Mr. Havens' other great enthusiasm was shooting pictures with old-school cameras, such as Leicas, and posting them on Instagram. He was co-host of a podcast called Classic Lenses, where he was described as "CEO of Lens Purchasing, Wearer of Manly Shorts."

He was devoted to his wife, Pam, and their son, Andrew, Payne said. His death "is such a loss to science."

Senior news researcher Caryn Baird contributed to this story. Contact Craig Pittman at craig@tampabay.com. Follow @craigtimes.