Saving Seafood

The oceans’ circulation hasn’t been this sluggish in 1,000 years. That’s bad news.

April 11, 2018 — The Atlantic Ocean circulation that carries warmth into the Northern Hemisphere’s high latitudes is slowing down because of climate change, a team of scientists asserted Wednesday, suggesting one of the most feared consequences is already coming to pass.

The Atlantic meridional overturning circulation has declined in strength by 15 percent since the mid-20th century to a “new record low,” the scientists conclude in a peer-reviewed study published in the journal Nature. That’s a decrease of 3 million cubic meters of water per second, the equivalent of nearly 15 Amazon rivers.

The AMOC brings warm water from the equator up toward the Atlantic’s northern reaches and cold water back down through the deep ocean. The current is partly why Western Europe enjoys temperate weather, and meteorologists are linking changes in North Atlantic Ocean temperatures to recent summer heat waves.

The circulation is also critical for fisheries off the U.S. Atlantic coast, a key part of New England’s economy that have seen changes in recent years, with the cod fishery collapsing as lobster populations have boomed off the Maine coast.

Some of the AMOC’s disruption may be driven by the melting ice sheet of Greenland, another consequence of climate change that is altering the region’s water composition and interrupts the natural processes.

Read the full story at the Washington Post

Ocean Acidification Could be a Net Positive for Some Fish

March 30, 2018 — One of the consequences of pumping more and more carbon dioxide into the atmosphere is the changing chemistry of the world’s oceans. Until now, the ocean has acted as a big sponge, soaking up about one-third of the CO2 released by human activities.

But now, scientists are watching a vast experiment unfold. All that carbon dioxide is triggering chemical reactions that is turning the oceans more acidic, which in turn is making life tough for lots of marine organisms. Oysters and other shellfish have been hit by die-offs in the Pacific Northwest and Gulf of Maine, while tropical reefs are dissolving faster than they can rebuild, according to a recent study in the journal Science.

Some researchers are seriously considering geoengineering to reverse the slow acidification of the ocean. Dissolving minerals like olivine or limestone into seawater would increase its alkalinity. (Remember the pH strip in your 10 gallon fish tank? Blue=alkaline, red=acidic.) Not only would that make it easier on marine life, but it would also allow the ocean-sponge to soak up more carbon dioxide from the atmosphere. Two British scientists proposed this idea last year in a paper in the journal Reviews of Geophysics, predicting that with a bit more research (and money) it may be possible to capture hundreds of billions to trillions of tons of carbon without messing up the marine ecosystem.

But this kind of massive planetary experiment needs lots of small-scale work in the laboratory before it’s ready. So in the meantime, marine scientists are trying to find which species will come out on top in a more acidic ocean.

In Sweden, a group of researchers tested survival in an artificially acidic ocean. In a fjord, they built an enclosed, floating test tube they called a “mesocosm” and filled it with phytotoplankton, zooplankton, and tiny herring larvae. Then they turned up the dissolved carbon dioxide, tracking herring survival over time as the acidity increased.

A similar lab experiment with codfish, another important Northern European food fish, killed off the fish. “Our surprise is that we didn’t find that,” said Catriona Clemmesen-Bockelmen, a marine ecologist from the GEOMAR Helmoltz Center for Ocean Research in Kiel, Germany, and a co-author on the study in Nature Ecology and Evolution. “Instead, we had a higher survival rate.” The herring, it seemed, liked the extra acidity.

Read the full story at Wired

 

Endangered status of Atlantic sturgeon up for review

March 27, 2018 — Federal fishing regulators say they are conducting a five-year review of threatened and endangered populations of Atlantic sturgeon.

Populations of sturgeon are listed as threatened in the Gulf of Maine and endangered in New York Bight, the Chesapeake Bay and off the Carolinas and South Atlantic.

The National Oceanic and Atmospheric Administration says the Endangered Species Act requires the agency to conduct the review to ensure the listings are still accurate. The listings are intended to be based on the best available scientific data.

The Atlantic States Marine Fisheries Commission said last year that a sturgeon stock assessment indicated the population is still very low compared to its historical abundance. They face threats such as climate change, ship strikes and fishing.

Sturgeon suffered overfishing in the 20th century when it was harvested for eggs for caviar.

Shortnose sturgeon are listed under the Endangered Species Act (ESA) as an endangered species throughout their range. Atlantic sturgeon are listed as five distinct population segments with those that hatch out in Gulf of Maine rivers listed as threatened, and those that hatch out in other U.S. rivers listedas endangered.

Once thought to number less than 100 in the Merrimack, the river’s shortnose sturgeon population has been on the rebound, researchers have said. Atlantic sturgeon are also found in the Merrimack, up to the Essex Dam in Lawrence.

Two distinct groups of adults, numbering more than 2,000, inhabit the river. One group includes fish born in Haverhill’s spawning grounds, while the other consists of fish born in Maine rivers such as the Kennebec and Androscoggin, which migrate to the Merrimack.

Researchers say that for much of the year, sturgeon are looking for food in the lower part of the Merrimack — from Amesbury to the Joppa Flats in Newburyport — and live there from November to March.

Haverhill is the only place in the river where sturgeon lay their eggs, and that happens in the spring.

Read the full story at the Gloucester Times

 

Warming world will affect fish size and fisheries

March 26, 2018 — Current fishery targets may become unachievable as the planet warms.

A new study, led by Plymouth Marine Laboratory (PML), has found that the proportion of large  in the North Sea may decrease as climate change unfolds, by as much as 60% in some areas. The effects of warmer waters and ocean acidification may mean proposed fisheries management targets based on fish size could be unachievable if the effects of  on fish size are not considered.

Using state-of-the-art modelling and comparison with real-life surveys, the researchers demonstrated they can simulate how fish size is changing in our marine environment, under the pressures of fishing and environmental factors. This form of modelling, combining important indicators and environmental change, can help with sustainable exploitation of fished stocks by helping policy makers consider how wild populations are impacted by changing, warmer and more acidic oceans into the future.

Indicators based on fish size are widely used in the study and management of wild populations exploited by commercial fishing. The Large Fish Indicator (LFI) is one such example, determining the biomass of fish above a certain size in a community, and used to inform policy and guide the .

While widely used, however, these types of indicators have not previously been used alongside predictions of future conditions in line with expected climate change. Fish size closely reflects the environment, and a warming world will change the conditions in which fish live. It has been suggested that rising water temperatures in the North Sea, for example, are driving down fish size in key species. By modelling North Sea fish populations alongside predicted  for LFI, scientists have shown how  may affect fish communities, and what it may mean for fisheries.

Read the full story at PHYS

 

Climate change threatens coastal life as we know it

March 9, 2018 — The Gulf of Maine is getting warm — quick. From 2004–2013, sea temperatures there rose faster than almost any other location on Earth.

Why it matters: The Gulf is home to a number of endangered species, and the fisheries there bring in several billion dollars per year to the U.S. and Canada, but the Gulf’s future hangs in the balance. Researchers are scrambling to understand what the warming water means for the people and animals who rely on the ecosystem, particularly as the changes there provide a glimpse into the future of coastlines around the world.

Why it’s warming

The Gulf of Maine lies at the intersection of several major ocean currents, including the Atlantic meridional overturning circulation, which moves dense, cold water down and toward the equator. Fresh water from melting sea ice seems to be weakening this current, which could be causing the Gulf to warm faster than other regions.

A combination of cold winters, warm summers, and dramatic tides make the Gulf one of the most productive ecosystems in the ocean. It’s a critical habitat for right whales, seabirds like puffins, humpback whales, bluefin tuna and other species.

Read the full story at Axios

 

These Chinook almost went extinct during California’s drought. Can this $100 million plan save them?

March 9, 2018 — During the worst of California’s five-year drought, thousands of eggs and newly spawned salmon baked to death along a short stretch of the Sacramento River below Shasta Dam.

The winter-run Chinook, already hanging by a thread, nearly went extinct.

Hoping to avoid a repeat of that dire scenario, fisheries officials announced Thursday the launch of a plan — nearly 20 years and $100 million in the making — they say would expand the spawning range of the fish to include a cold-water stream called Battle Creek. The idea is that the stream could keep the fragile winter-run alive as California’s rivers get hotter because of a warming climate.

The stakes are high and go well beyond the fate of the fish. Concerns about this run of salmon have a major impact on how water is distributed to farms and cities across California.

During the drought, for example, farmers experienced cuts to their water supply as dam managers held water in Shasta, the state’s largest reservoir, in a frantic effort to ward off extinction of the Chinook.

Read the full story at the Sacramento Bee

Climate change draws invasive species to the Arctic

February 27, 2018 — The Arctic is changing. Temperatures are increasing twice as fast as the global average and sea ice is retreating quicker than predicted.

It is now just a question of time before the Arctic becomes ice free in summer.

But while we humans react slowly to the problem at hand, evidence suggests that animals are on the move- on land, sea, and in the air. And in the cold Arctic, invasive species are drawn to regions where they could not previously have survived.

But invasive species pose a big problem for native animals, whose numbers can decline to the point of collapse. They also pose a threat to fisheries, with economic consequences on both a local and global scale.

In fact, our recent study showed that blue mussels have become much more common in the Arctic in recent years, just like other exotic species of bluefin tuna and killer whales.

Read the full story at Phys.org

 

To get good credit, Alaska’s fishing towns may have to factor in climate change

February 15, 2018 — Late last year one of the world’s largest credit rating agencies announced that climate change would have an economic impact on the U.S.

Moody’s suggested that climate risks could become credit risks for some U.S. states.

Even though Alaska is warming nearly twice as fast as the rest of the U.S., its credit rating doesn’t seem to be in danger. But take a closer look at some of the state’s coastal communities and the story changes, especially when Alaska’s fishing towns consider adding climate risks to their balance sheets.

Frank Kelty is the mayor of the Unalaska, a tiny town is on an island sandwiched between the Bering Sea and the Gulf of Alaska, near some of the richest fishing grounds in the world.

Kelty has been there for 45 years, and lately, he’s seen a lot of changes.

“We’ve had a huge increase in humpback whales coming right into the inner harbor by the road system. Just hundreds of them hanging around,” he said.

People have been pulling off of the road to watch what he calls the “whale show.”

Read the full story at KTOO

 

Ocean Acidification Threatens Our Shellfish

February 2, 2018 — The Massachusetts legislature is current considering a number of bills regarding ocean acidification. If passed into law, the bills will establish a special commission or task force to study the effects of coastal and ocean acidification on coastal communities, fishing and aquaculture industries, and local commercially-harvested species. These bills come at a very critical time when what we do or don’t do next to address the effects of ocean acidification could very well alter the Commonwealth’s culture and economy.

What is ocean acidification?

Excess carbon dioxide in our atmosphere from the burning of fossil fuels is driving climate change and along for the ride is increased global temperatures, rising sea levels, and increased storm intensity. We hear about it almost daily. But on a planet that’s 70 percent ocean, what’s happening below the waves? They call it global warming’s evil twin: ocean acidification.

Much like the atmosphere, the ocean is absorbing more and more carbon dioxide. As a result, ocean temperatures are not only rising, but the actual chemistry of the ocean is changing. Research estimates that the ocean has become 30 percent more acidic since the Industrial Revolution. In particular, the Gulf of Maine is especially vulnerable because its colder waters can absorb more carbon dioxide than other ocean areas. Massachusetts’ bays and sounds are among those waters impacted by ocean acidification.

Why do we need to act?

Ocean acidification should be very alarming to Massachusetts and its legislators because it poses a grave threat to the Commonwealth’s shellfish fisheries – the most valuable in the Commonwealth. Increased ocean acidity interferes with the ability of shell-forming organisms such as clams, mussels, and oysters to build and maintain their calcium carbonate shells. The planktonic larval stages of many species are also vulnerable, a concern for hatcheries and wild populations of shellfish.

Read the full story at TalkingFish

 

GLOUCESTER TIMES: Lobster industry’s discipline staves off collapse

February 1, 2018 — Conservation pays off.

For years, lobstermen in the Gulf of Maine have been returning large and egg-bearing females to the water, instead of selling them for a short-term profit. The long-held practice, called “v-notching” because the females’ tails are marked to alert other lobstermen of their fertility, has kept the lobster stock healthy. A 5-pound lobster can produce another thousand lobsters in its lifetime, fisheries scientists say. A 1.5-pound lobster produces about 100. The last several years have been some of the most profitable in the industry’s history.

Now, it looks like those years of self-restraint are going to help the industry weather a new challenge — climate change.

In a report released late last month, scientists predicted the Gulf of Maine lobster population will drop as much as 62 percent over the next 30 years. The change is coming as the waters warm, making it more difficult for baby lobsters to survive. That’s the bad news.

The good news is that the conservation efforts used over the past several decades by lobstermen from Rockport and Gloucester to the state of Maine fostered exponential growth in the lobster population. Ironically, the warming waters also helped, until the temperature rose past a healthy level for young lobsters.

Read the full editorial at the Gloucester Times