2123. Fish Stocks Are Declining Worldwide, and Climate Change Is on the Hook

By Clare Lechin-Hoar, NPR, December 14, 2015

A fisherman shovels grey sole, a type of flounder, out of the hold of a ship at the Portland Fish Pier in Maine, September 2015. New research finds the ability of fish populations to reproduce and replenish themselves is declining across the globe. The worst news comes from the North Atlantic, where most species are declining. Photo: Gregory Rec/Portland Herald via Getty Images.

For anyone paying attention, it's no secret there's a lot of weird stuff going on in the oceans right now. We've got a monster El Nino looming in the Pacific. Ocean acidification is prompting hand wringing among oyster lovers. Migrating fish populations have caused tensions between countries over fishing rights. And fishermen say they're seeing unusual patterns in fish stocks they haven't seen before.

Researchers now have more grim news to add to the mix. An analysis published Monday in the Proceedings of the National Academy of Sciences finds that the ability of fish populations to reproduce and replenish themselves is declining across the globe.

"This, as far as we know, is the first global-scale study that documents the actual productivity of fish stocks is in decline," says lead author Gregory L. Britten, a doctoral student at the University of California, Irvine.

Britten and some fellow researchers looked at data from a global database of 262 commercial fish stocks in dozens of large marine ecosystems across the globe. They say they've identified a pattern of decline in juvenile fish (young fish that have not yet reached reproductive age) that is closely tied to a decline in the amount of phytoplankton, or microalgae, in the water.

"We think it is a lack of food availability for these small fish," says Britten. "When fish are young, their primary food is phytoplankton and microscopic animals. If they don't find food in a matter of days, they can die.”

The worst news comes from the North Atlantic, where the vast majority of species, including Atlantic cod, European and American plaice, and sole are declining. In this case, Britten says historically heavy fishing may also play a role. Large fish, able to produce the biggest, most robust eggs, are harvested from the water. At the same time, documented declines of phytoplankton made it much more difficult for those fish stocks to bounce back when they did reproduce, despite aggressive fishery management efforts, says Britten.

When the researchers looked at plankton and fish reproduction declines in individual ecosystems, the results varied. In the North Pacific — for example, the Gulf of Alaska — there were no significant declines. But in other regions of the world, like Australia and South America, it was clear that the lack of phytoplankton was the strongest driver in diminishing fish populations.

"When you averaged globally, there was a decline," says Britten. "Decline in phytoplankton was a factor in all species. It was a consistent variable."

And it's directly linked to climate change: Change in ocean temperature affects the phytoplankton population, which is impacting fish stocks, he says.

Food sources for fish in their larval stage were also a focus of research published earlier this summer by Rebecca Asch, now a post-doctoral research associate at Princeton University. Asch studied data from 1951 to 2008 on 43 species of fish collected off the Southern California coast and found that many fish have changed the season when they spawn. When fish spawned too early or too late in the season, there can be less plankton available to them, shrinking their chance of survival. She calls it a "mismatch" between when the fish spawn and when seasonal plankton blooms.

Knowing just how vulnerable our fisheries are to potential climate change is on the radar of NOAA Fisheries. The agency has put together a Fish Stock Climate Vulnerability Assessment report expected to be released in early 2016. And like many things associated with climate change, there will be winners and losers.

Jon Hare is the oceanography branch chief for NOAA Fisheries' Northeast Fisheries Science Center and a lead researcher on the agency's assessment. He says they looked at 82 fish and invertebrate species in the Northeast. About half of the species, including Atlantic cod, were determined to be negatively impacted by climate change in the Northeast U.S. Approximately 20 percent of the species are likely to be positively impacted—like the Atlantic croaker. The remainder species were considered neutral.

Similar assessments are underway in the California Current and the Bering Sea, and eventually in all of the nation's large marine ecosystems.

"This is where the idea of ecosystem-based management comes in. It's not only fishing that is impacting these resources," says Hare. "We need to take a more holistic view of these resources and include that in our management.”

Britten says the fact that productivity of a fishery can change should be an eye-opener for fisheries management.

"It's no longer just pull back on fishing and watch the stock rebound. It's also a question of monitoring and understanding the ability of stocks to rebound, and that's what we demonstrated in this study. The rebound potential is affected as well," says Britten.

1722. Where Have All the Cod Gone?

By W. Jeffrey Bolster, The New York Times, January 1, 2015

PORTSMOUTH, N.H. — IN November, regulators from the National Oceanic and Atmospheric Administration shut down recreational and commercial cod fishing in the Gulf of Maine, that enchanting arm of the coastal sea stretching east-northeast from Cape Cod. 
They did not have much choice: Federal law requires action to rebuild fish stocks when they are depleted, and recent surveys revealed cod populations to be at record lows, despite decades of regulations intended to restore them.

It’s easy to imagine this recent drop in the cod population as a new phenomenon — a result, perhaps, of global warming, or some combination of climate change and overfishing by giant steel ships armed with electronic fish-finders and precise GPS navigation systems. And it’s just as easy to imagine that, after a season or two of belt-tightening, fish populations will rebound — it is, after all, a strategy that state and federal regulators have pursued for decades.

In fact, humans have been affecting the Atlantic’s fish stocks for centuries, beginning with technology so simple that people today would not even consider it “technology.” Forgetting that history, we opt for short-term fixes, which only compound the problem.

The fishery resources of the western Atlantic once seemed virtually limitless, with fish supposedly as numerous as grains of sand in the Sahara. And yet the current emergency effort to restore cod populations is simply the latest chapter in a 150-year saga in which fishermen, scientists, industrialists and politicians have consistently confronted emptier nets and fewer fish.

As early as the 1850s, fishermen from Maine and Massachusetts began to pester their governments to do something about declining cod catches. Those men fished with hooks and lines from small wooden sailboats and rowboats. Fearing “the material injury of the codfishing interests of this state” by increased fishing for menhaden, a critical forage fish for cod, fishermen from Gouldsboro, Me., implored the Legislature in 1857 to limit menhaden hauls.

Yet annual cod landings in the Gulf of Maine continued to slide, from about 70,000 metric tons in 1861 to about 54,000 metric tons in 1880, to about 20,000 tons in the 1920s, to just a few thousand metric tons in recent years. There have been a few upticks along the way, such as one bumper year in the mid-1980s when the cod catch reached 25,000 tons (due, in part, to an unnecessarily large expansion of the fishing fleet), but for the most part the trend has been noticeably downward since the era of the Civil War. There have been plenty of warnings along the way. Maine’s fishery commissioner, Edwin W. Gould, spoke out plainly in 1892. “It is the same old story,” he said. “The buffalo is gone; the whale is disappearing; the seal fishery is threatened with destruction.” For Mr. Gould, the path forward was clear: “Fish need protection.”

In July 1914, after more than 40 years of reports on declining fishery resources by the United States Fish Commission and state fish commissions, The New York Times ran an article forecasting disaster. “Extermination Threatens American Sea Fishes — Cost to Consumer Has Risen between 10 and 600 Per Cent Because of Decrease in Supply.”

But that was right before a technological revolution in the fisheries. Sails and oars and hooks and lines were about to be replaced by steam and diesel engines, and massive nets dragged along the bottom that snared every fish in their path. Decades of well-founded concerns about depletion were overwhelmed by an avalanche of cheap fish. The new generation of draggers could fish faster, harder and deeper for the few fish that remained. Fishermen breathed a sigh of relief.

Twentieth-century cod populations, ravaged by draggers’ efficiency, declined further. In 1954 a fisheries economist from Boston charged fishing interests with continuing “to exploit recklessly the limited self-renewing stocks of these species.” That was just before the first factory-equipped freezer-trawler arrived at the prime fishing waters around the Grand Banks off Newfoundland from Europe. The size of an ocean liner, it could scoop up everything in its wake. Those ships made the steam-powered draggers from 1914 look positively quaint. And they caught lots of fish.

Overfishing has been the norm for a very long time, but the market has masked the mess in two fundamental ways. At every step fishermen confronting declining catches developed gear that fished more intensively, taking a larger percentage of the fewer fish that remained. Such a strategy was clearly not sustainable. Meanwhile, fishermen continued to earn enough to make fishing worthwhile, even if many encouraged their sons to pursue other careers because there would be little future in fishing. The Gulf of Maine cod stocks today are probably only a fraction of 1 percent of what they were during George Washington’s presidency.

If there is any lesson in this story of large-scale, long-term environmental degradation, it is not that fishermen were (or are) to blame, or that scientists were (or are) to blame, or that politicians were (or are) to blame. The system was (and is) to blame. Our system of exploiting nature’s resources, with its checks and balances, its desire for prosperity and security, its willingness to honor a multiplicity of voices, and its changing sense of “normal” is insufficiently nimble to stop the desecration of commonly held resources on which the long-term good of everyone depends.

The recent ban on cod fishing in the Gulf of Maine was an important step toward restoration, though clearly marine systems are very complex and subject to many variables. Considering that ban in light of history, however, is crucial. Historical perspectives provide a vital sense of scale for the sobering restoration challenges we face.

The fisheries story, however, also provides a heading into the future, revealing as it does the tragic consequences of decision makers’ unwillingness to steer a precautionary course in the face of environmental uncertainties. At every step of the way, decisions could have been made to exploit fish stocks more sustainably. That’s a tale worth pondering.