The letter asks lawmakers to instead focus on various ways to improve what already exists.

"A few voices calling for the overturn of the entire ... system have been amplified in the media," the letter reads. "Unfortunately, this has led to a series of increasingly dangerous proposals that truly put the future of our businesses and fisheries at risk."

The letter comes about a month after Sens. Scott Brown of Massachusetts and Kelly Ayotte of New Hampshire introduced a new bill that could wipe out the new system, if more than 15 percent of participating fishermen lost their jobs in the first year. But fisheries advocates say the letter was about more than Brown's bill.