For about 30 years, Portland has been engaged in a long conversation over how to best use its waterfront.

In the early ’80s there was the development of condominiums on Chandler’s Wharf, which was followed by the citizen-initiated referendum that limited the piers to water-dependent businesses only.

Now the pier owners have successfully campaigned to relax those rules, opening up just under half of the ground floor space in their buildings for restaurants, offices, shops and other non-water-dependent businesses. The zoning change received the blessing of the Maine Department of Environmental Protection last week, opening the door to development that has not been possible for many years.

The new zoning is not a total reversal: Another Chandler’s Wharf project could not be built under these rules, which don’t permit residential development on the waterside. And 55 percent of ground floor space is still reserved for processors, bait dealers and other businesses that cannot operate away from the water.

This is another attempt to get the balance right, and it should be seen that way. The working waterfront is a rare resource that needs to be protected as well as exploited. If it turns into a sterile business district, Portland would likely lose what remains of the combination of commercial fishing and heavy industry that not only provides jobs to the people who work in those fields but also gives the city its history and character.

The pier owners have made a compelling argument that overly restrictive zoning actually hurts the working waterfront because they don’t collect enough income to support dredging and other improvements needed to keep their dilapidated properties functioning. Now it’s the pier owner’s turn to show that they can find businesses that want to coexist with the sights, sounds and even smells of a real working waterfront, and that success of those other businesses will result in more investment in the marine infrastructure.

This change should not be seen as a rejection of working waterfront protection but a way to help it work better. It’s the latest part of a long conversation, and it should not be considered the last word.