YARMOUTH — The Maine lobster industry is being threatened by a lack of supply of herring, the bait fish crucial to the industry. Rivers like our Royal River in Yarmouth once upon a time had a run of alewives, a local species of herring. The annual migration of these fish was familiar to the people who lived here.

Today, Casco Bay and the Gulf of Maine are bereft of groundfish like cod, haddock and flounder – all of which feed off the diminished herring population. And now our lobster fishery, which contributed $495 million to the Maine economy in 2015, is having difficulty finding enough baitfish.

It is essential, therefore, for us to ensure a healthier Casco Bay, to begin at the bottom of the food chain, by rebuilding the population of herring. Free-flowing rivers will enable herring to spawn in greater numbers, which in turn will help rebuild our bottom fisheries and lobster populations. Our celebration of World Fish Migration Day on the Royal River last spring was just the first of a series of events that we are planning over the next year to call attention to the plight of our native fish populations.

On World Fish Migration Day, which took place May 21, over 450 events were held around the world to celebrate healthy rivers and the fish that swim in them. In Yarmouth, along the banks of our beloved Royal River, approximately 500 people joined a dedicated alliance of concerned environmentalists to learn about the river’s past, present and future health.

Why is fish migration so important, you ask? Fish migration is essential for healthy rivers. Migratory fish all over the world depend on free-flowing rivers.

Today, river barriers like dams and other obstacles threaten the survival of many fish species. Free-flowing rivers allow fish to travel upstream, increase fish populations in the river and ensure a healthy river life.

Hundreds of years ago, before the European settlers came to Maine, the region looked very different. Free-flowing rivers roared their way out to the Gulf of Maine. And a dozen species of native sea-run fish migrated up Maine’s rivers every year.

But with the damming of our rivers to accommodate industrial development and the need for power, there came along pollution and huge declines in native fish populations. Now, early in a new century, we face the prospect of crashing marine fish populations as the years of river neglect have caught up with us. We can’t go back in time, but we can work together toward a better future.

Can we save our Gulf of Maine fishery? There are many success stories that we can point to. The Penobscot, Kennebec and St. Croix rivers are all waterways that have had fish migration obstacles removed and have seen immediate results. State fisheries biologists have declared that the Kennebec now annually hosts the largest river-herring run in the United States.

And the restoration doesn’t end with just the fish. Eagles, osprey, great blue heron, gulls, terns, cormorants, seals, whales, otter, mink, fox, raccoon, skunk, weasel, fisher, snakes, turtles – many other creatures are sustained by consuming fish that come from our rivers.

Healthy rivers lead to healthy communities for people, too. Researchers now confirm that not only is exercise good for you, but there are added mental and physical health benefits from taking walks in a natural environment. And what better place to do that than along a river?

The walkway along the Royal River is precious to this community, but wouldn’t it be great for our kids to experience that stretch of the river with an annual run of migratory fish and the accompanying birds that follow to feed on them?

Our planet is one large interconnected ecosystem. Our rivers feed into Casco Bay, which in turn is part of the Gulf of Maine and the oceans of the world. In Yarmouth, we are hoping to restore the health of our Royal River, which in turn will help ensure a healthy Casco Bay, a healthy Gulf of Maine and a healthy planet for the generations who will follow. Yarmouth’s Royal River is a small part of a larger system, but we together are its stewards.