Matt Rigney thinks that if people spent as much time out on the ocean as he does, they might have a better appreciation for how imperiled much of the sea’s creatures are.

Rigney, 44, has spent much of his life sport fishing, looking for big fish. But in 2007, a National Geographic magazine series about the global “ocean crisis” made him feel outrage over the damage fishing, shipping and other activities were having on marine life.

And since Rigney’s family has long had a home in Kennebunkport, he was specifically concerned about what was happening in the Gulf of Maine.

So Rigney, who lives most of the year near Northampton, Mass., and works as an educational consultant, decided to write a book about his adventures in sport fishing and his encounters with majestic marine life.

“Unless you bring people out there, they probably have no idea what it’s like to encounter these fish,” said Rigney.

Rigney traveled waters around the world to write his book, “In Pursuit of Giants: One Man’s Global Search For the Last of the Great Fish” (Viking, $26.95). The book went on sale in June.

Q: Why did you want to write this book?

A: Because I was outraged when I realized what was happening to the ocean, specifically the Gulf of Maine — overfishing, shipping, have caused so much damage. I wanted to deal with the issues from the perspective of a sport fisherman, and bring people out on an adventure to encounter these fish.

Q: What was your goal?

A: I wanted to persuade people that the ocean and the life in it are not just resources, but part of a complex ecosystem. It has to be looked at in a more nuanced way. The book is an adventure story about encountering these animals, and it’s clearly a conservation book. I’m opposed to certain practices — like bottom dragging. But basically I think what we’re doing is squabbling over crumbs of what used to be an enormous pie. We need to grow back the pie as much as possible.

Q: How did you begin?

A: I thought, if I care about this I’ve got to do what I can. There are a number of good books about problems with the ocean, but none of them deal with encountering these huge fish. I wanted a book for the everyday reader, where they could feel like they were with me as I went to these places around the world to encounter these fish face to face, so they could better understand what is happening.

I went to places like the Great Barrier Reef off Australia. Most people are lucky to see a thousand-pound marlin once, but I saw two in one morning. I was on the Greenpeace ship Rainbow Warrior in the Mediterranean. I was talking to fishermen in Nova Scotia. Over five years (while also working) I traveled 75,000 miles, to Nova Scotia, Mexico, Japan, Australia, New Zealand and the Mediterranean.

Q: How did you afford the travel?

A: I got an advance on the book, but I blew through that pretty fast. The rest was from my savings, and by the good graces of people who wanted to support what I was doing.

Q: What do you hope people get out of this book?

A: I think anyone who wants to know more about the ocean, about fish, would find this a good, basic introductory on commercial and recreational fishing. And I think it will give people an idea of what the great creatures of the ocean are like up close.

Staff Writer Ray Routhier can be contacted at 791-6454 or at: [email protected]