Saving Seafood

Melting ice poses fleeting ecological advantage but sustained global threat, Stanford scientist says

August 31, 2018 — From collecting field samples inside the ocean’s frozen ice pack to analyzing satellite images in the comfort of his Stanford office, Kevin Arrigo has been trying to figure out how the world’s rapidly thinning ice impacts polar food chains. Arrigo, a professor of Earth system science at Stanford School of Earth, Energy & Environmental Sciences, found that while melting ice threatens to amplify environmental issues globally, ice sheet retreat can provide much-needed food in local ecosystems.

Through this work, Arrigo discovered that thinning ice at the poles can alleviate polar food deserts by extending phytoplankton blooms. However, the silver lining associated with melting ice cannot make up for imminent threats, such as rising sea levels, associated with unchecked glacial shrinkage.

Arrigo, who is also the Donald and Donald M. Steel Professor in Earth Sciences, spoke with Stanford Report about his work on polar phytoplankton blooms and discussed whether recent news about sea ice breaking up suggests we’ve reached a tipping point.

What have you learned about how glacial melt impacts food chains in the extreme environments of the poles?

It turns out that when glaciers form, they accumulate particles and dust that contain essential nutrients like iron, on which all living things depend for survival. As glaciers melt, they add nutrients to the ocean and fertilize the local ecosystem. In Greenland and Antarctica, the ocean is short on iron, so melting glaciers make up for the lack of iron.

Read the full story at Stanford News

 

Waters off New England in midst of record year for warmth

August 31, 2018 — The waters off of New England are already warming faster than most of the world’s oceans, and they are nearing the end of one of the hottest summers in their history.

That is the takeaway from an analysis of summer sea surface temperatures in the Gulf of Maine by a marine scientist with the Gulf of Maine Research Institute in Portland. The average sea surface temperature in the gulf was nearly 5 degrees Fahrenheit above the long-term average during one 10-day stretch in August, said the scientist, Andy Pershing, who released the work Thursday.

Aug. 8 was the second warmest day in recorded history in the gulf, and there were other sustained stretches this summer that were a few degrees higher than the average from 1982 to 2011, Pershing said. He characterized this year as “especially warm” even for a body of water that he and other scientists previously identified as warming faster than 99 percent of the global ocean.

Read the full story from the Associated Press at ABC News

Global fisheries could still become more profitable despite global warming

August 30, 2018 — Researchers from Japan’s Hokkaido University, the University of California, Santa Barbara (UCSB), National Center for Ecological Analysis and Synthesis, and Environmental Defense Fund  (EDF) found that harvesting sustainable amounts of seafood globally over the next 75 years can lead to higher total food production and profits, even taking into consideration the fish populations which are projected to decline as the ocean warms and habitats change.

This is because, under what has been determined as the best management scenario, some major fish and shellfish stocks that are commercially harvested, broadly referred to as fisheries, will grow and become more profitable, offsetting the many others projected to shrink or even disappear. On a global average, profitability could rise by 14 billion USD and harvest by 217 million metric tons above today’s levels, according to the study.

There is a catch. In the model, the growth was achieved under the projected moderate warming of 2.2°C (3.9°F) above average global temperatures by 2100. But if temperatures rise further, global fish harvest and profits are expected to decline below today’s levels even with the best management in place.

The researchers say their study, published in Science Advances, conveys an important message: the oceans can continue to be a source of healthy seafood and sustainable livelihoods for billions of people, but only if action is taken to manage the stocks well and limit the carbon emissions that drive climate change.

Read the full story at Science Daily

Fish populations could rise in warming climate with better management

August 30, 2018 — Better management of fisheries and fishing rights around the world could increase profits and leave more fish in the sea as long as measures to meet climate obligations are taken, new research has found.

Even if temperatures rise by as much as 4C above pre-industrial levels – in the upper range of current forecasts – the damaging effects on fishing can be reduced through improving how stocks are fished and managed.

Governments are meeting from 4 September in New York for the first round of talks on a new global treaty of the high seas, which would aim to conserve overfished stocks and make access to key fisheries more equitable. Any agreement is likely to take several years to negotiateand longer to come into force, but scientists say there is no time to be lost, given the magnitude of the threat to the world’s marine ecosystems.

Climate change is already causing the movement of some species as their traditional habitats grow warmer, and overfishing is wreaking heavy damage on stocks. However, by adapting fisheries management to a warming climate, and instituting better systems such as monitoring of fleets, the global catch can be increased despite these factors, according to the paper published on Wednesday in the journal Science Advances.

“This is a positive message amid the doom and gloom,” said Kristin Kleisner, one of the authors of the study and a senior scientist at the US Environmental Defense Fund. “We can control how we manage our fisheries. We will have severe effects [from climate change] but this shows what we can do as humans to control that.”

Read the full story The Guardian

Climate Change Impacts On Cold Water Fishing

August 23, 2018 — Each year, more than 49 million Americans fish recreationally in freshwater rivers and lakes. Some fish to relax, and some for the thrill. But in a changing climate, a new generation of anglers will have to get used to conditions far different from those of their parents and grandparents. Warming water in streams, rivers, and lakes is changing the habitats and behavior of fish, and resulting in a wide range of impacts in different parts of the U.S.

Cold water fish, like trout and salmon, struggle in warmer water. The amount of dissolved oxygen in the water drops as the water warms, causing the fish to become less active. For these fish, that critical temperature is about 70°F. In the Northwest, a general decline in snowpack has led to lower streamflows and warmer water in spring and summer, meaning that the 70°F threshold is exceeded more often. Montana has recently closed some rivers to recreational fishing, even for catch-and-release, because of physical stress on the fish.

Although smallmouth and largemouth bass do just fine at water temperatures above 70°F, which are more common in the Southeast, the warmer water creates a more active breeding ground for bacterial infections and parasites. In the Northeast, a 2005 die-off of smallmouth bass in the Susquehanna River was traced to a bacterial disease called Columnaris, which becomes more contagious at higher water temperatures. And in the Great Lakes, warmer water has increased the size and feeding rates of the parasitic sea lamprey, which latches onto and devastates trout, salmon, perch and catfish. Just one sea lamprey can kill 40 pounds of fish during its 12-18 month feeding period.

The best time of the year for fishing is also changing in a warming climate, which has an economic impact on communities across the country. Bass, salmon, and shad in the Pacific Northwest and trout in New England are migrating or spawning earlier in the year. Anglers who plan vacations based on the best time year to fish may find the peak of the season has passed by the time they arrive. In addition to the disappointment, this mistiming can affect everything from businesses selling fishing equipment and operating field guides to housing and hospitality revenues. All told, freshwater fishing contributed $41.9 billion to the to the U.S. economy in 2016.

Read the full story at KBZK

MAINE: Odds may be bad for winter shrimp fishery

August 22, 2018 — Scientists gathered at a downtown hotel last week for a three-day “peer review” of the latest Northern Shrimp Benchmark Stock Assessment from by the Atlantic States Marine Fisheries Commission.

The assessment evaluates the condition of the Gulf of Maine northern shrimp resource and provides regulators with the information they need to manage the fishery.

The sessions were mostly open to the public but, as of Tuesday morning, the ASMFC had yet to publish a summary of the proceedings.

Whatever happened, the odds are against the fisheries managers allowing any shrimp fishing this coming winter.

Last year’s stock report showed that stock abundance and biomass between 2012 and 2017 were the lowest on record during the 34 years records have been kept. The 2017 numbers were the lowest ever observed.

Recruitment — the number of animals entering the fishery — has been poor since 2011 and includes the four smallest year classes on record.

There is little to suggest those numbers are likely to improve.

Recruitment of northern shrimp is related to both spawning biomass and ocean temperatures, with higher spawning biomass and colder temperatures producing stronger recruitment.

Read the full story at The Ellsworth American

Can dogfish save Cape Cod fisheries?

August 21, 2018 –Low clouds hang over the pier as fishing boats line up to drop off their catch for the day. Fishermen in orange suspendered waders and rugged boots perch on the edges of their boats. The fishermen, with weathered faces and hands toughened by their work, ignore the tourists gawking and snapping photos from a viewing platform overhead.

Then, the fog descends, giving the scene a sense of timelessness. But this scene has changed from decades past. For 400 years, fishermen across Cape Cod caught boatloads of, well, cod. The fish was so plentiful and valuable that fishermen bought houses and new boats off cod profits alone. But today, there’s a different fish filling the piers: spiny dogfish.

Cape Cod has nearly lost its namesake fish, due to overfishing and climate change. So fishermen have switched to dogfish, skates, and other more plentiful options. This move could help revive the Massachusetts fishing industry, and might even help the cod rebound, researchers say. But getting Americans to bite may not be as easy.

“This is the fish we could feed the United States with,” says Chatham fisherman Doug Feeney. “We have people that are hungry. We have prison systems. We have vets. We have homeless people. There’s just so much that can be done with this product.”

For a long time, fishermen saw dogfish as an annoyance. They were a “trash fish” with little value that often ended up clogging their nets. The large spines on their fins especially made them a pain to throw back, and they eat pretty much everything smaller than them – including juvenile codfish.

Read the full story at The Christian-Science Monitor

Climate Change Is Cooking The Oceans

August 16, 2018 — Heat waves aren’t just for land lubbers. Climate change has turned the oceans into cauldrons of scalding water, upending marine ecosystems around the world.

A new paper in Nature shows how marine heat waves have become more common and intense in recent decades, largely due to climate change. What’s worse, it shows that even if the world manages to limit warming to two degrees Celsius, the trend will continue and humans will ultimately be the main driving force for virtually every marine heat wave. If we let the world warm past that mark, the results could be catastrophic for the high seas.

The results point to the need to get marine life ready for a world of extreme heat and also take a greater focus on protecting the ocean wilderness we have left.

The role of human-caused climate change in intensifying land-based heat waves is now well-established. But less research has focused on the ocean, where extreme heat events in recent years have wiped out portions of the Great Barrier Reef, caused bull sharks to migrate further north, and left scientists scrambling to find ways to save coral. Individual events like the 2016 heat wave in the Great Barrier Reef have been tied to climate change (it made the heat wave 175 times more likely), but there hasn’t been a big picture look at the topic featuring projections into the future.

That’s what led a team of Swiss researchers used a mix of models and satellite measurements to get a handle on how marine heat waves have already changed and what the future holds for the globe. The satellite record, which runs from 1982-2016, helped ground truth the models they used to create a pre-industrial baseline—what the oceans looked like without all the extra heat trapped by greenhouse gas emissions. They then used the models to understand how climate change is affecting the extent, duration, and intensity of marine heat waves as well as project future changes.

The findings show the number of marine heat wave days doubled between 1982 and 2016, while heat waves also increased in extent and intensity. Moreover, they show that 87 percent of marine heat waves can be attributed to climate change, meaning they would not have occurred without it.

Read the full story at Gizmodo

Why sharks are thriving near the North Carolina coast

August 15, 2018 — Climate change is negatively impacting our relationship with our state’s coast. Our famous beaches are taking a heavy hit from rising sea levels. Meanwhile, loss of property, loss of natural coastal habitats, and changes to our fisheries threaten our economic well being.

Sea levels are rising especially fast in the southeast, bringing potentially devastating losses to property values and real estate. Hurricane damage and chronic flooding due to rising seas a huge concerns. By 2045, more than 15,000 homes are at risk of being flooded on more than 26 days every year.

In addition to the property losses, so much sand is being eroded from beaches at Nag’s Head that the state spent $36 million to pump new sand from the sea floor onto beaches in 2014 and will spend $48 million in 2018. This brings total state spending on beach nourishment since 1990 to $640 million. The rising costs of beach nourishment impacts our state’s coastal tourism economy, which brought in an estimated $3 billion in 2013 according to N.C. Department of Commerce. With sea level predicted to rise at least 1 foot and by as many as 8 feet by 2100, there is much at risk.

Sea-level rise is not our only problem. Pamlico Sound had changed from an occasional feeding ground to a shark nursery as a direct result of climate change. Pamlico Sound already had many of the features of a good bull shark nursery: ocean access, proper salinity, and plenty of prey fish. The only missing piece was warmer water temperature. While adult bull sharks have been occasionally encountered in the sound for a long time, the sudden appearance and consistent presence of juveniles after 2011 signaled a change that has been correlated with rising water temperatures, particularly during late spring and early summer when bull sharks give birth.

Read the full story at The News & Observer

Warming waters and migrating fish stocks could cause political conflict

August 8, 2018 — Climate change is driving fish species to migrate to new areas, and in the process they’re crossing political boundaries – potentially setting up future conflicts as some countries lose access to fish and others gain it, according to a recent study published in the journal Science.

Already, fish and other marine animals have shifted toward the poles at an average rate of 70 kilometers per decade. That rate is projected to continue or even accelerate as the planet warms.

When fish cross into new territory, it might prompt competitive harvesting between countries scrambling to exploit disappearing resources.

“Conflict leads to overfishing, which reduces food, profit, and jobs that fisheries can provide, and can also fracture international relations in other, non-fishery sectors,” Malin Pinsky, the lead author of the study and an assistant professor of biology at Rutgers University, told SeafoodSource.

The study looked at the distribution of nearly 900 commercially important marine fish and invertebrates, examining how their movements intersect with 261 of the world’s Exclusive Economic Zones. By 2100, more than 70 countries will see new fish stocks in their waters if greenhouse gas emissions continue at their current rates.

Cutting greenhouse gas emissions could reduce the scale and number of these migrations by half or more, Pinsky said.

Conflict over shifting fish stocks is not unheard of. In the 2000s, migrating mackerel in the northeast Atlantic caused such a rift between Iceland and other nations that it played a role in derailing attempts to join the European Union. In the eastern Pacific, a bout of warm ocean temperatures in the 1980s and 1990s shifted salmon spawning patterns, prompting a scuffle between U.S. and Canada.

Read the full story at Seafood Source