Plenty more fish in the sea?

New method for measuring biomass reveals fish stocks are more stable than widely believed

Fish and marine species are among the most threatened wildlife on earth, due partly to over exploitation by fishing fleets. Yet there are differences in assessing trends in worldwide fishing stocks which, researchers writing in Conservation Biology argue, stem from inappropriate use of time trends in catches.  Trevor Branch “Estimates of fishery status based on catches suggest that around 30% of fisheries are collapsed and 70% are overexploited or collapsed,” said lead author Dr Trevor Branch from the University of Washington in Seattle. “Our assessment shows that these data are seriously biased, and that instead we should be looking at biomass data.Biomass data from scientific stock assessments indicated a much smaller proportion in these categories (12% collapsed, 26% overexploited or collapsed), and that status trends are stable. Our analysis suggests that in most regions fisheries management has led to stabilization, and even recovery, of fished populations.” “Species which are targeted by fishing fleets are divided into stocks, a division of species into units based on political boundaries, genetic divergence, and biological characteristics,” said Branch. “The depletion of these stocks has important implications for ecosystem biodiversity; however methods of measuring depletion vary greatly.” Dr Branch’s team considered stocks being “collapsed” or “overexploited” on the basis of catch and biomass data. Collapse is defined as biomass of less than 10% of unfished levels while over exploitation is defined by the governments of the United States and Australia as biomass below 50% of biomass that would produce maximum sustained catches.  These reference points are widely used in fisheries management, either as management targets or as limits not to be exceeded. Previous methods for assessing status were on the basis of catch trends, however, methods based on biomass data find much lower percentages that are collapsed or over exploited, and relatively stable future trends. “Our study found the status of stocks worldwide based on catch trends to be almost identical to what would be expected if catches were randomly generated with no trend at all,” said Branch, “and that most classifications of collapse on the basis of catch data are not true collapses but are due to taxonomic reclassification, regulatory changes in fisheries, and market changes.” Where biomass data are available, this can be used to ground truth the catch trends; this shows that catch data greatly overestimates the percentage of stocks collapsed and overexploited. Although the team’s biomass data was primarily from industrial fisheries in developed countries, the status of these stocks estimated from catch data is similar to the status of stocks in the rest of the world estimated from catch data. “Instead of focusing on what we take out of the oceans (catches), we should be examining the actual state of the ecosystem (biomass data),” concludes Branch. “Catch data produce seriously biased estimates of what is going on in ocean ecosystems, and we need more effort expended on scientific surveys and stock assessments, especially in areas that are currently poorly assessed.” This paper is published in Conservation Biology. Fore more information contact Lifesciencenews@wiley.comThis e-mail address is being protected from spam bots, you need JavaScript enabled to view it  +44 (0) 1243 770 375 Full Citation:  Branch TA, Jensen OP, Ricard D, Ye Y, Hilborn R, “Contrasting global trends in marine fishery status obtained from catches and from stock assessments”, Conservation Biology, March 2011, DOI

Impacts of Biodiversity Loss on Ocean Ecosystem Services [research article]

By Boris Worm, et al.

Dr. Boris Worm

Human-dominated marine ecosystems are experiencing accelerating loss of populations and species, with largely unknown consequences.

We analyzed local experiments, long-term regional time series, and global fisheries data to test how biodiversity loss affects marine ecosystem services across temporal and spatial scales. Overall, rates of resource collapse increased and recovery potential, stability, and water quality decreased exponentially with declining diversity.

Restoration of biodiversity, in contrast, increased productivity fourfold and decreased variability by 21%, on average.

We conclude that marine biodiversity loss is increasingly impairing the ocean’s capacity to provide food, maintain water quality, and recover from perturbations. Yet available data suggest that at this point, these trends are still reversible.

Click to read the entire article.

Pregnant? Eat Fish!

Excerpt from Dr. Weil’s article on the Huffington Post mentions Ray Hilborn’s New York Times op-ed…

Dr. Andrew Weil

Founder and director of the Arizona Center for Integrative Medicine

“…while many worry that overfishing has depleted much of the world’s fish stock, “fish stocks worldwide appear to be stable, and in the United States they are rebuilding, in many cases at a rapid rate,” according to a recent New York Times Op-Ed piece by Ray Hilborn, a professor of aquatic and fishery sciences at the University of Washington. Even if this were untrue and fish were scarce, pregnant women would still be the most deserving recipients of this dwindling resource — and should be absolutely the last group to have to give up fish.”

Read the rest of the article on the Huffington Post.

The Road to End Overfishing: 35 Years of Magnuson Act

Assistant Administrator Schwaab for Fisheries Talks about the Cornerstone of Sustainable Fisheries

photo © 2010 Deepwater Horizon Response | more info (via: Wylio)

As we look toward Earth Day next week, I want to acknowledge and highlight the 35 th anniversary of the Magnuson-Stevens Fishery Conservation and Management Act. Simply called “the Magnuson Act”, this law, its regional framework and goal of sustainability, has proven to be a visionary force in natural resource management – both domestically and internationally. The Magnuson Act is, and will continue to be a key driver for NOAA as we deliver on our nation’s commitment to ocean stewardship, sustainable fisheries, and healthy marine ecosystems

Because of the Magnuson Act, the U.S. is on track to end overfishing in federally-managed fisheries, rebuild stocks, and ensure conservation and sustainable use of our ocean resources. Fisheries harvested in the United States are scientifically monitored, regionally managed and legally enforced under 10 strict national standards of sustainability. This anniversary year marks a critical turning point in the Act’s history. By the end of 2011, we are on track to have an annual catch limit and accountability measures in place for all 528 federally-managed fish stocks and complexes. The dynamic, science-based management process envisioned by Congress is now in place, the rebuilding of our fisheries is underway, and we are beginning to see real benefits for fishermen, fishing communities and our commercial and recreational fishing industries.

But, we did not get here overnight. Our nation’s journey toward sustainable fisheries has evolved over the course of 35 years. At this particular moment it is important to take time and reflect back on where we have been to understand where we are and fully appreciate the historic visions and strategic investments that got us here, particularly by the Act’s principal architects, the late U.S. Senators Warren G. Magnuson of Washington State and Ted Stevens of Alaska.

Read the rest on SavingSeaFood.org.

Ocean acidification – changing planet (video)

As higher amounts of carbon dioxide become absorbed by the oceans, some marine organisms are finding it’s a struggle to adjust.

The Changing Planet series explores the impact that climate change is having on our planet, and is provided by the National Science Foundation & NBC Learn.

The End of Overfishing in America

A fisherman unloads a portion of his catch for the day at Pigeon Cove Whole Foods docks in Gloucester, Massachusetts. Eric Schwaab, the administrator of the National Marine Fisheries Service, announced this week that overfishing will end in U.S. waters. (AP/Lisa Poole)

 

By Michael Conathan | March 25, 2011

This feature is part of a new series from CAP dealing with fisheries management issues. The series will publish biweekly on Fridays. It is a joint column with Science Progress.

Eric Schwaab, the administrator of the National Marine Fisheries Service, or NMFS, stood before a crowd of fisheries experts on Monday at the Boston Seafood Show. Schwaab had made many forays to New England—home of some of the squeakiest wheels in our nation’s fishing industry—since taking over the job about a year ago. But this time was different. He came bearing a remarkable message: We are witnessing the end of overfishing in U.S. waters.

One of the biggest changes to fisheries law in the 2007 reauthorization of the Magnuson-Stevens Fishery Conservation and Management Act was the imposition of strict annual catch limits, or ACLs, in fisheries experiencing overfishing beginning in 2010, and for all other fisheries in 2011, “at a level such that overfishing does not occur.” Schwaab said the 2010 target of putting ACLs in place for all overfished fisheries was achieved, and “We are on track to meet this year’s deadline of having [ACLs] in place, as required, for all 528 managed stocks and complexes comprising U.S. harvest.”

Schwaab went on to call this accomplishment an “enormous milestone.” Quite frankly, that is an even more enormous understatement.

The end of overfishing should be shouted from rooftops from New England to the Carolinas to the Gulf Coast to Alaska to the Pacific Island territories and back to NMFS’s Silver Spring, Maryland headquarters. This is the biggest national news story our fisheries have seen in years.

Read the rest of the story from America Progress.

Fisheries chief sees end to overfishing

March 22, 2011

By Richard Gaines Staff Writer

Shifting spring: Arctic plankton blooming up to 50 days earlier now

By Brian Vastag
Washington Post Staff Writer

A light micrograph of plankton including water fleas (family Daphniidae) (Getty Images/oxford Scientific)

Climate researchers have long warned that the Arctic is particularly vulnerable to global warming. The dramatic shrinking of sea ice in areas circling the North Pole highlights those concerns.

A new report finds that the disappearing ice has apparently triggered another dramatic event – one that could disrupt the entire ecosystem of fish, shellfish, birds, and marine mammals that thrive in the harsh northern climate.

Each summer, an explosion of tiny ocean-dwelling plants and algae, called phytoplankton, anchors the Arctic food web.

But these vital annual blooms of phytoplankton are now peaking up to 50 days earlier than they did just 14 years ago, satellite data show.

“The ice is retreating earlier in the Arctic, and the phytoplankton blooms are also starting earlier,” said study leader Mati Kahru, an oceanographer at the Scripps Institution of Oceanography in San Diego.

Read the rest of the story here.

What Role Is Ocean Acidification Playing In Shellfish Losses?

No new Pacific oysters recruiting to oyster “beds.”
Shellfish larvae dying at commercial hatcheries.
Corrosive, acidified seawater measured for the first time off the Pacific Coast.

These and other observations, beginning in 2005 on the West Coast, prompted members of the shellfish industry to seek help from scientists to explore what is causing the shellfish losses, what role ocean acidification (OA) and other factors might be playing, and how to adapt to sustain West Coast shellfish resources.

Scientists, oceanographers, state and federal agency managers, and industry members participated in a workshop in 2010 to frame the problems, assess what information is available and what is needed, and to suggest future actions.

Photo credit: Richard Wilson, Willapa Bay, WA

The California Current Acidification Network (C-CAN) evolved from that meeting as participants and others interested in ocean acidification agreed on the need to facilitate and enhance communications, education and research collaborations among scientists, academia, agencies and industry.

The need for education is clear:, Increasing levels of carbon dioxide (CO2) emissions into the atmosphere, a consequence of fossil fuel use, are causing immediate, measurable impacts on ocean chemistry.

About one-third of the carbon dioxide produced every day around the world is absorbed by the oceans. As CO2 reacts with seawater, it lowers seawater pH and reduces the concentration of carbonate ions, an essential component in the calcium carbonate that makes up the shells of shellfish and the skeletons of corals. Recently scientists have begun measuring changes in ocean chemistry and investigating the possible consequences to marine life, food webs and people. These studies find that ocean acidification is ongoing and may have significant biological impacts. The West Coast is vulnerable to the enhanced ocean acidification associated with seasonal upwelling, potentially causing serious impacts to ecosystems and some recreationally and commercially important shellfish.

Watch this video produced by NBC Learn for more information.

Dr. Ray Hilborn: ‘The end of overfishing,’ what does it mean?

Ray Hilborn

Dr. Ray Hilborn examines the end of overfishing in the United States. He addresses what fisheries managers can control and what is in the realm of nature, beyond the reach of human management.

(SEAFOOD.COM NEWS) – Feb 7, 2011 – The following article from Ray Hilborn is in response to NMFS chief scientist Steve Murawski’s widely reported comments last month that US overfishing as ended. This is part of a continuing series of occasional articles on fisheries and conservation topics by Ray Hilborn, Professor at the School of Aquatic and Fishery Sciences, University of Washington, prepared for Seafood.com News.

Overfishing has ended in the U. S. said Professor Steve Murawski, former chief fishery scientist for NOAA on January 8th 2011.

Could this possibly be true?

With many fish stocks still at low abundance, subject to rebuilding plans and listed as overfished, how could he argue that overfishing has ended?

To understand the issue we first must begin with the distinction between “overfished” and “overfishing.” Overfished is a term used when the abundance of the stock is low enough that its sustainable yield is significantly reduced. Overfishing is when the percentage harvested is higher than required to provide long term maximum sustainable yield. So “overfished” is about abundance and “overfishing” is about the percentage we harvest.

What Murawski said is that the percentage harvested for all U. S. federally managed fish stocks is now within the range that would produce maximum sustainable yield.

We have stopped fishing too hard; but many fish stocks remain at low abundance.

Read the rest of the story on SavingSeaFood.org.