Other than catching the biggest striped bass, bluefish, false albacore or bonito during the Martha’s Vineyard Striped Bass and Bluefish Derby, catching all four species might be the most difficult feat a derby angler can accomplish. Catching all four species on a flyrod is rarer still.

But that’s exactly what Zach Horrocks, a professional outfitter and guide from Lake Placid, N.Y., has done this year.

It’s no fluke. He did it last year too. In the 2016 derby it took him until the fourth week of the fishing tournament to complete the achievement, fishing from his 19-foot Pathfinder center console boat. This year, with hard fishing and the good fortune of good weather, he weighed in all four species in the first week.

“My bluefish and my bass were up in the rocks fishing real tight,” he told the Gazette. “I’ve got a special little small boat that I can get up into the wash. All sight fishing, spotting the fish, stalking them, putting a good shot on them. The bonito and the albie were both south of the Island, out there in this really stormy weather, just before the hurricane, fishing the big swell. No one else was out there. I got it all done in one week. I was trying to get it done before this storm. I was pretty happy. I was definitely pretty excited.”

It’s called a grand slam, and just like in baseball, tennis, or golf, it puts the contestants on a revered plane of extraordinary skill. Each of the four species is an individual target, requiring its own special knowledge, skill and tackle to hook and land. Of course, all the knowledge and skill in the world does not amount to much without perseverance. Zach Horrocks has plenty of that.

“The last four or five years, my priority has always been the grand slam,” said Mr. Horrocks. “That’s my challenge. I won the fly rod grand slam last year, that was my first priority this year. Priority number one.”

It would be a mistake to imagine that the grand slam in two consecutive years lessens the difficulty of the exploit. Mr. Horrocks has long been frustrated in the pursuit.

“I’ve always gotten three out of the four,” said Mr. Horrocks. “It always drove me nuts. Then last year I kind of figured out the last little bit. I had a good year. For me it’s always the bones or the bass. There are years where there are just not one or the other around, or they’re hard to find on a fly. Probably the bass is the toughest thing for me.”

Like many flyrod enthusiasts, Mr. Horrocks ties his own flies. Experience honed his knowledge and led to a recent change in the flies he fashions from bird feathers, animal hair and other materials.

“I’ve adjusted my fishing to more of the fly tying, understanding the four different species of fish,” said Mr. Horrocks said. “I’m kind of tying four separate styles of flies to target these big fish. Last year I figured out a certain style of fly, using much bigger flies. All of a sudden it started triggering those much bigger fish.”

Mr. Horrocks, 29, has his own guide service in Lake Placid, stalking the native species in upstate New York. For a kid who loves fishing, a dream childhood.

“I think this is my 25th year of the derby,” he said. “My dad has been doing the derby 30-something years. I always came here for at least four or five weeks of the derby every year. He always pulled me out of school, shot me up here.”

Now, his guide seasons align perfectly with fishing the derby on Martha’s Vineyard, though one has to wonder if it’s all that much of a coincidence.

“I typically have about a month off between the end of my trout season and the beginning of my hunting season,” said Mr. Horrocks. “I always come down for three or four weeks.”

If you ask derby veterans about Mr. Horrocks, the reply is usually some variation on the theme of: “That guy can fish,” or, “Really nice guy.”

Those are compliments he does not take lightly.

“It means a lot coming from the guys at the derby,” Mr. Horrocks said. “It’s always been my favorite thing to do, every year. I do a lot of fishing back home for trout and bass and pike, but my heart always kind of lies in saltwater. This is for me, a lot of fun.”