Hot water for fisheries management

As climate change deepens, we’ll need to understand entirely new marine ecosystems.

Here’s the good news: Since 1990, the catch of Maine lobsters has quintupled.

Okay, the rest of the news, as in other stories about climate change, is not so good.

The bumper crops of lobsters apparently have been driven by warming in the Gulf of Maine. Sea surface temperatures have climbed about four times as much in recent decades in the Gulf as in the global ocean average, according to Andrew Pershing, chief scientific officer at the Gulf of Maine Research Institute.

Lobster populations have moved northeast from southern New England waters,  Pershing said, speaking at a Metcalf Institute seminar on climate change held in Cambridge last Saturday. The shift has been a boon for Maine but a bust for fisheries south of Cape Cod.

Warmer water in the Gulf also has knocked down populations of other marine life, including some we eat (or once ate) such as northern shrimp and cod.

For hundreds of years, cod in the northwest Atlantic was one of the world’s richest fisheries. Back in the 1970s, my older brother took a trip to Georges Bank as a whale watcher on a giant Russian factory ship. At night, the sea looked like a city, dotted with the lights of dozens of fishing vessels busily sucking up cod and everything else on the seafloor.

Cod never recovered. The U.S. soon took control of our waters out 200 miles and managed the seafood take as well as it could. But most of the cod we eat now comes from China or Iceland.

Today climate change is delivering not just disruptions in ocean temperature and circulation patterns but acidification, extreme storms, loss of mangroves and marshes… As fisheries are disrupted around the world, the familiar difficulties of managing them get worse.

We don’t really know how to model newly emerging marine ecosystems, Tatiana Rynearson of the University of Rhode Island remarked at the Metcalf session. We lack the years of data needed to understand the fluctuations in conditions and populations, as Jorge García Molinos and colleagues pointed out in a 2015 paper.

Our need for long-term ocean monitoring and related research couldn’t be clearer, but climate change research is under heavy attack in the U.S.

Fortunately, compared to most of the waters of the world, we do have good historical information on Gulf of Maine waters and seafood. And while lobsters are a luxury food, they offer a positive example for management.

Unlike the case in some other states, Maine fishers must toss back lobsters that are too big as well as too small. Simulations have shown that saving the big ones has helped the shellfish survive the fishing onslaught in the Gulf, where 90% of legal-size lobsters are caught each year, Pershing said.

The saga of Maine lobsters, of course, rolls on. The catch dropped significantly in the last two years, and the highest landings keep moving north.

Watching the river flow

The Thames Barrier is still prepped for decades defending London against high water.

On Tuesday, the warmest winter day ever recorded in Britain, there was not a cloud in the sky over the Thames Barrier. A tug calmly pulled its barge through one of the channels in the Barrier, which shuts off the Thames when the incoming tide will rise over sixteen feet. This offbeat superdam doesn’t look like anything else: a necklace of giant steampunk silver mussel shells stretched a third of a mile across the river. London began seriously contemplating means of protection after a major dousing in the great North Sea storm of 1953. The Barrier went into operation three decades later. It has decades of usefulness ahead; although climate change was not considered in its design, sea levels along the southern English coast aren’t inching up from geologic causes as fast as originally expected. The Barrier has been shut about 200 times, 50 of them in the 2013/2014 season, when the culprit was not super surges from the ocean but super rain surges that incoming tides would have pumped up further. “It is designed to be bomb-proof and failure-proof,” the Londonist once noted. “When a 3,000-tonne dredger hit the Barrier in 1997, the ship sank. The Barrier lost a ladder.” One of these decades, the enormous wall may be supplemented by a much more enormous dike downstream. In the meantime, “the structure is fundamental to the lives of millions of Londoners,” the London Review of Books commented, “which may be the reason very few of them want to look at it.”

Canaries in a coal-mined world

Environmental writers tell great stories about life across our fast-changing globe.

We’re seeing a remarkable series of stories about climate change and other manmade or partly manmade threats—some even complete with hints of solutions. Here’s a fairly random baker’s dozen from this striking crop (hmm, only two of these pieces come from for-profit publications).

Public Spectacle

A beacon of hope in a changing climate.

kid Spectacle

On a clear hot August day you can take a ferry to Spectacle Island and walk a winding path up to its northern summit, admiring wildflowers and eating blackberries. The summit is the highest point of land on Boston Harbor, with low wooded islands scattered around.

Off to the east you can spot a windmill near the huge sludge-digesting eggs of Deer Island, and a second windmill a few miles south at the tip of the Hull peninsula. These two points of land bracket the entrance from Massachusetts Bay to the harbor’s inner archipelago.

One distant day, Deer Island and Hull also may anchor a massive sea barrier, holding off an ocean that’s now projected to climb as much as eight feet by 2100.

Today it’s hard to imagine how we might start to build such a Big Dike, given our current politics.

But you can also see hopeful signs on this Spectacle for our ability to clean up our own messes.

The first time I sailed past the island it was a garbage dump, with the remnants of a horse-rendering plant buried under many feet of still-smoldering refuse.

Now that’s all taken away and replaced by fill from the Big Dig. The island was reengineered and replanted. Rich ecosystems began to reappear. On summer days like this, children swim a stone’s throw away from the site of the old factories.

In wildness is the preservation of the world, as Thoreau said. But not just in wildness.