Concerned that overfishing is destroying the ability of menhaden to reproduce, the commission that manages the Atlantic coast fishery voted Wednesday to sharply reduce the catch.

Tiny, oily menhaden are called the ocean’s most important fish by environmentalists because they provide food for essential fish such as striped bass and for birds such as osprey, bald eagles and brown pelicans. Without menhaden, environmentalists say, the Atlantic Ocean and Chesapeake Bay ecosystems would come crashing down.

At a meeting in Boston, the Atlantic States Marine Fisheries Commission voted 14-3 to cut the amount of menhaden that can be harvested annually from 183,000 metric tons to 174,000 metric tons. The commission must now draft and vote on a plan to implement the new rule, which is likely to become effective in May 2013, spokeswoman Tina Berger said.

A single company, Omega Protein, took 160,000 metric tons of menhaden — 80 percent of about 450 million fish harvested last year — off the coast of Virginia, the only state that permits industrial fishing of menhaden. The company crushes the fish into meal to feed livestock and farmed fish around the world.

In the run-up to the vote, the 45-member commission received more than 91,000 letters, the vast majority of which urged members to drastically reduce the catch. States from Maine to Florida each have three members — only one each can vote.

The commission wants 30 percent left to spawn. That would nearly quadruple the current threshold of 8 percent.

Menhaden stocks are in steep decline: 50 years ago, about 90 billion were a year old or less, according to commission estimates. Twenty-five years ago, there were 70 billion. Now only 18 billion menhaden that age remain.

“Certainly there was concern about the population,” Berger said, explaining the commission’s vote.