Saving Seafood

Studies investigate marine heatwaves, shifting ocean currents

September 22, 2020 — In a paper published September 17 in the Journal of Climate, WHOI oceanographers and collaborators at the GEOMAR Helmholtz Centre for Ocean Research Kiel in Germany use a new model to understand how ocean processes affect marine heatwaves at depth off the west coast of Australia. Known as “Ningaloo Niño,” these extreme warming events have caused mass die-offs of marine organisms, coral bleaching, and potentially permanent ecosystem shifts, all of which impact fisheries and the economies that depend on them.

“This area is a hotspot for increasing temperature and extreme events, with drastic impacts on regional marine species,” said lead author Svenja Ryan. “It’s important to understand where in the water column temperature and salinity changes are happening so you can determine how the ecosystem will be impacted.”

For the first time in the Southern Indian Ocean, Ryan and her co-authors, WHOI physical oceanographers Caroline Ummenhofer and Glen Gawarkiewicz, showed that the effects of marine heatwaves extend to 300 meters or more below the surface along the entire west coast of Australia. They found that during La Niña years, the southward-flowing Leeuwin Current becomes stronger and is associated with warm temperature anomalies at greater depths. These conditions were observed during the 2011 marine heatwave that led to the first-recorded coral bleaching at Ningaloo Reef, a World Heritage site, and extensive loss of a nearby kelp forest. During El Niño periods, the temperature and salinity anomalies associated with marine heatwaves are limited to the ocean surface, showing that complex ocean processes play an important role in the depth-extent of extreme events.

Ryan and her colleagues are using a similar modeling approach to study marine heatwaves in the Northwest Atlantic. “The challenge, wherever you go, is that marine heatwaves have so many drivers,” Ryan said. “Understanding different types of events and their associated depth structure is crucial for regional impact assessment and adaptation strategies, as well as for predicting potential changes in a future climate.”

Read the full story at Science Daily

Marine animals live where ocean is most breathable, ranges may shrink with climate change

September 17, 2020 — As oceans warm due to climate change, scientists are trying to predict how marine animals—from backboned fish to spineless jellyfish—will react. Laboratory experiments indicate that many could theoretically tolerate temperatures far higher than what they encounter today. But these studies don’t mean that marine animals can maintain their current ranges in warmer oceans, according to Curtis Deutsch, an associate professor of oceanography at the University of Washington.

“Temperature alone does not explain where in the  an animal can live,” said Deutsch. “You must consider : how much is present in the water, how well an organism can take up and utilize it, and how temperature affects these processes.”

Species-specific characteristics, overall  and water temperature combine to determine which parts of the ocean are “breathable” for different ocean-dwelling creatures. New research led by Deutsch shows that a wide variety of marine —from vertebrates to crustaceans to mollusks—already inhabit the maximum range of breathable ocean that their physiology will allow.

Read the full story at PHYS.org

The future of food from the sea, explained

September 15, 2020 — In the year 2050, Earth will have almost 10 billion humans who will eat over 500 billion kilograms of meat. That is 2 billion more people and 177 billion more kilograms of meat than Earth currently has. With land-based meat fraught with climate and environmental impacts, how much animal protein can be sustainably supplied by the ocean? A new (open access) paper in Nature titled, The Future of Food from the Sea, answered that question and provided an economic roadmap for sustainable ocean food production.

The authors conclude that by 2050, the ocean could sustainably provide 80-103 billion kilograms of food, a 36-74% increase compared to the current yield of 59 billion kilograms. Crucially, the 2050 numbers were not a simple calculation of the carrying capacity of food production, but instead reflected the economic realities of growing and harvesting food in the ocean. The authors identified four key steps towards a more bountiful ocean:

  1. Improve fishery management
  2. Implement policy reforms to address mariculture
  3. Advance feed technologies for fed mariculture
  4. Shift consumer demand

In this post, I explain the numbers behind potential food production in the ocean and what the policy and governance process might look like going forward.

Read the full story at Sustainable Fisheries UW

Ecosystem-Based Fisheries Management Strengthens Resilience to Climate Change

September 15, 2020 — The following was released by NOAA Fisheries:

Ecosystem-based fisheries management (EBFM) has been applied in Alaska for decades with great success. Alaska’s valuable commercial fisheries are among the most productive and sustainable in the world. However, current EBFM policies were not designed to address climate change.

A new study evaluates the future performance of EBFM in the eastern Bering Sea. The innovative experiment projects that EBFM can forestall climate-driven collapse of key Alaska fisheries better than other management policies. This management approach considers the impacts on fish stock productivity from environmental variables, such as changing ocean conditions, and socio-economic factors. It can help fishery managers and fishermen in planning for the future.

“Ecosystem-based management doesn’t just help fish, it helps fishing communities. It is the best strategy we have to provide harvest stability in the coming years. It buys time for Alaska fisheries and fishing communities to prepare and adapt. EBFM is going to be a vital tool for us under climate change,” said Kirstin Holsman, biologist at NOAA Fisheries’ Alaska Fisheries Science Center. “But no matter how effective management is, by mid-century—maybe sooner—Alaska fisheries may reach a tipping point of rapid decline in the eastern Bering Sea if climate change continues on the current trajectory and fish and fisheries are not able to adapt to these changing conditions. To guarantee long-term success, we need to couple EBFM with global climate change mitigation.”

Read the full release here

Study finds declines in size of Alaska salmon

September 15, 2020 — A recent study that dove into more than 60 years of records from the Alaska Department Fish and Game found that salmon returning to Alaska’s rivers are on average smaller than they were in the past.

The study, headed up by biologists from the University of California Santa Cruz and the University of Alaska, Fairbanks, attributes declines in salmon size to “shifting age structures associated with climate and competition at sea.”

Read the full story at Seafood Source

NOAA taps David Legates, professor who questions the seriousness and severity of global warming, for top role

September 14, 2020 — The Trump administration has tapped David Legates, an academic who has long questioned the scientific consensus that human activity is causing global warming, to help run the agency that produces much of the climate research funded by the U.S. government.

Legates, a University of Delaware professor who was forced out of his role as that state’s climatologist because of his controversial views, has taken a senior leadership role at the National Oceanic and Atmospheric Administration (NOAA).

The agency, which oversees weather forecasting, climate research and fisheries, has until now continued its climate research and communications activities unfettered by political influence. For that, NOAA stands in stark contrast to the Environmental Protection Agency and science agencies at the Interior Department, where the Trump administration has dismissed and sidelined climate scientists or altered their work before publication.

The move to install Legates as the new deputy assistant secretary of Commerce for environmental observation and prediction, a position that would report directly to acting NOAA Administrator Neil Jacobs, is raising concerns in the science community that this could be a White House-orchestrated move to influence the agency’s scientific reports.

Read the full story at The Washington Post

Artificial Reefs Take on a Towering Presence as Havens for Marine Predators

September 10, 2020 — The following was released by Duke University:

Acting like high-rise timeshares in the sea, shipwrecks and other artificial reefs can support dense populations of sharks, mackerels, barracudas, jacks and other large migratory marine predators essential to ocean health, according to a new study at 30 sites along the North Carolina coast.

Predator densities were up to five times larger at the 14 artificial reefs surveyed in the study than at the 16 nearby natural reefs that also were surveyed

Shipwrecks, especially those that rose between 4 and 10 meters up into the water column, were by far the fishes’ favorite. At some sites, they supported predator densities up to 11 times larger than natural reefs or low-profile artificial reefs made of concrete.

“These finding tell us two important things. One is that artificial reefs can support large predators, potentially supplementing natural reefs if the design and placement of the artificial reefs are strategic,” said Avery Paxton, research associate with the National Oceanic and Atmospheric Administration’s National Centers for Coastal Ocean Science (NCCOS) in Beaufort, N.C., who led the study.

“The second thing it tells us is that when it comes to designing artificial reefs, there may be such a thing as a height advantage. We observed more fast-moving predators that live and hunt in the water column at the taller reefs in our study,” she said.

Climate change, pollution, development and other stresses have accelerated the decline of natural reef ecosystems across much of the world’s oceans in recent years, forcing large predators who formerly fed in the water column around the reefs to venture outside their normal migratory routes and native ranges in search of suitable alternatives.

Because these predators help maintain healthy and sustainable populations of species lower in the food web, providing suitable habitat for them as expediently as possible is critical, said Brian Silliman, Rachel Carson Distinguished Professor of Marine Conservation Biology at Duke University’s Nicholas School of the Environment, who collaborated on the study.

Read the full release here

UMaine’s ‘hot water’ study will examine lobster industry’s vulnerable areas

September 9, 2020 — Maine’s lobster fishery faces serious challenges related to climate change.

But a new research project at the University of Maine will develop indicators of resilience for the lobster industry that can be used to detect where the industry is most vulnerable to climate change.

The research will be led by UMaine in collaboration with the lobster industry, the Maine Department of Marine Resources, Maine Center for Coastal Fisheries and Maine Lobstermen’s Association.

UMaine was awarded $125,808 for the project, called “Fishing in hot water: Defining sentinel indicators of resilience in the American lobster fishery,” by the Sea Grant American Lobster Initiative.

The initiative is funded by the National Oceanic and Atmospheric Administration’s National Sea Grant College Program.

Read the full story at MaineBiz

PFMC: Ad Hoc Climate and Communities Core Team online meeting September 29, 2020

September 8, 2020 — The following was released by the Pacific Fishery Management Council:

The Pacific Fishery Management Council’s (Council) Ad Hoc Climate and Communities Core Team (CCCT) will hold an online meeting, which is open to the public. This meeting will be held Tuesday, September 29, 2020, from 3 p.m. to 4:30 p.m. Pacific Time, or when business for the day has been completed.

Please see the CCCT meeting notice on the Council’s website for details.

For further information:

  • Please contact Pacific Fishery Management Council staff officer Dr. Kit Dahl at 503-820-2422; toll-free 1-866-806-7204.

ALASKA: Harbor porpoise bycatch near Point Barrow contributes to larger study on Bering Sea population

September 4, 2020 — When James Judkins began pulling up his fishing nets out near Point Barrow this month, the weight of the catch pulled back at him.

“Man, this is a really big fish,” Judkins thought. Then, he glimpsed the dorsal fin. Then another. “Dolphins?” he wondered.

Close. Harbor porpoises, a marine mammal resembling dolphins, but in the same family as whales, have made several appearances in Utqiaġvik recently.

In recent weeks, local fishermen have caught at least four porpoises in subsistence fishing nets near Point Barrow. Judkins recovered two, along with a seal, on Aug. 12 in Elson Lagoon. The other two were bycatches in Christian Stein and Charlie Sikvaguyak’s separate nets set in the same area. For some fishermen, it was their first time seeing the mammal.

Read the full story at the Anchorage Daily News