The Oak Bluffs Monster Shark tournament resumes this weekend when some of the top fishermen from up and down the East Coast descend on the Island in hopes of landing the prize-winning fish. But with it also comes the return of the debate over the ethical aspects of the event and opposition from several national animal rights groups.

In its early days the shark tournament was a low-key affair, largely viewed as a harmless fishing competition that attracted top fishermen while generating a moderate boost in business for local shops and restaurants.

But when ESPN began broadcasting the event in 2005, the tournament suddenly was exposed to a worldwide audience.

Interest in — and criticism of — the tournament escalated; and the event became a target for animal rights groups. A majority of the opposition comes from the Humane Society of the United States, which three years ago set up a booth during the tournament at Post Office Square in downtown Oak Bluffs and collected over 1,000 signatures from people opposed to the event.

Two years ago, ESPN stopped covering the event, and since that time the Oak Bluffs selectmen voted to end the practice of granting one-day liquor licenses for all shark tournaments, which prompted tournament organizer Steven James to move the headquarters for the event from the town-owned Washington Park to the Lampost nightclub on Circuit avenue.

Mr. James told the Gazette last year he would no longer speak with the newspaper because of an editorial on the tournament. He could not be reached for comment for this article. It is understood that the Lampost will once again serve as headquarters for the tournament this year.

Although the national Humane Society of the United States has once again launched a public campaign in opposition to the tournament, it has been done in a much more low-key manner. And while the event has generated statewide and even national attention in previous years, there now appears to be a noticeable lack of interest in the event among Islanders.

Opposition to the event reached a fever pitch just two years ago when the humane society placed an article on its Web site encouraging people to contact the Oak Bluffs board of selectman and Martha’s Vineyard Chamber of Commerce to express opposition to the tournament, which resulted in thousands of angry letters, phone calls and e-mails from people across the world.

Just last year the society angered town officials — many of whom had previously supported their cause — by suggesting the Oak Bluffs police department was somehow implicated in a high-stakes gambling scheme that took place during the tournament.

The society is running a full-color ad in today’s edition of the Gazette in opposition to the tourney. But there have been no visits to town selectmen this year, no campaign urging people to call Island officials, no letters to the editor, no public service announcements, and only a brief mention of the event on the society’s web site.

In fact, John W. Grandy, senior vice president of the Humane Society of the United States, told the Gazette yesterday there are no plans for representatives of the animal rights group to attend the tournament this weekend. He said the group remains fully committed to opposing and ending the tournament.

“Bringing an end to this barbaric, gruesome slaughter of these beautiful and important animals is still one of our priorities. . . . It will always be a priority,” he said.

Mr. Grandy said the society this year asked Mr. James to make the tournament a fully catch-and-release event, meaning all sharks caught would be measured, recorded and then returned to the ocean. He said the society recently helped convince the organizers of a shark tournament in Fort Myers, Fla. to switch to a full catch-and-release format.

Switching to a catch-and-release contest on the Vineyard would both save the lives of some sharks and send the message that killing sharks for sport is not acceptable, he said.

“Hunting big sharks doesn’t make sense anymore — if it ever did. To glorify the killing of a sharply declining species is shockingly out of step with the times. Relentless international fishing pressure has driven many shark species to the brink of extinction. And that includes some of the species that the boats streaming out of Oak Bluffs will hook and bring back to display in a grotesque celebration of death,” Mr. Grandy said.

Several people involved with the tournament said the number of boats that will participate in the tournament is down sharply, from around 235 boats just two years ago to around 125 boats this year as of yesterday.

Oak Bluffs harbor master Todd Alexander said he did not know the exact number of boats enrolled in the tournament. He said as of last week there are substantially fewer boats than previous years. He speculated there are fewer boats because of the faltering economy; the entry fee for the tournament this year was $1,375 if paid before May 3 and $1,475 if paid after that date.

“Times are tough this year. . . . The economy has been awful. I think people are thinking twice about spending that type of money,” he said.