conservationists were praising the success of a catch-and-release programme.

The 583-pound, 12-foot fish was caught by a honeymooning couple from Vermont as they neared the end of a marathon all-day fishing trip on the charter boat Sea Wolfe , skippered by Capt. Russ Young Jr.

Spokeswoman for the Sea Wolfe , Mrs. Hilda Young, said yesterday: "The captain asked the couple if they wanted to release it, but they wanted to take it in to have the mount. We would have preferred to have it put back. Our policy is to release as many as we can.'' This week Department of Tourism fishing consultant Mr. Tom Smith revealed the success of a conservation programme which encourages tourists to hang a special "certificate of release'' on the wall instead of a mounted fish. In 1991 the number of marlins released by charter boats doubled to 231 -- 80 percent of fish caught compared to 40 percent in 1985, when the programme began. The Sea Wolfe released 18 out of 22 caught last year.

This season's first blue marlin was caught 45 minutes after being hooked, 22 miles offshore, said Mrs. Young. "The people on their honeymoon were very excited.'' She stressed her business is very sensitive to the issue of conserving marlins. "This is only the second fish mount that we have had ordered this year. We would like to do replica mounts but there is very little time to photograph the fish because it is in a traumatic state, and you have to tag it before releasing it. And there's no certainty that they live once released anyway.'' Bookings are a cause for concern so far this year, she added.

Mr. Smith, who was called on to weigh the fish, said: "I wish the couple had released it. But it was their first one.'' The couple, Mr. and Mrs. Geoffrey Jackson, were not available for comment last night.

MARLIN FOR THE KILLING -- The first blue marlin of the season, caught by honeymooning couple Mr. and Mrs. Geoffrey Jackson. The fish was killed despite recent praise by conservationists on the success of a catch-and-release programme promoted by the Department of Tourism.