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Daily Fishing and Outdoor Report

3/5/14 Menhaden issue -- from the other side. It's well worth an objective read.

The following is a retort to efforts to reduce or eliminate commercial bunker harvesting. It is obviously biased toward commercialism -- but no more so than ongoing green efforts to protect all bunker from, let's say, any and all human intrusion.

I disagree with some of these retorts. I find them as unproven (unprovable) as the claims they're trying to debunk. However, I'm very intrigued by the distinction being made between "theoretically unfished population" and "virgin" stocks. It's a differentiation that deserves acknowledgement by all fishing interests -- commercial, recreational and managerial.  Virgin stocks are what might be called prehistoric stocks, prior to heavy human harvesting. In the US, that might be prior to 1600. 

The main problem with acknowledging virgin stocks is the inability to truly know what those stocks were, population-wise. I believe science can take an educated shot at it.

It is essential to realize that so-called base-year measurements used in fishery management are often folly if the base-year is placed within a period when a fishery is already distressed. Many say the striped bass fishery was hurt by such a base-year misplacement. Having other options to ponder -- like virgin, unfished, overfished populations -- allows for better management and conservation. 

Try reading the retort first (below) then go to http://limn.it/the-fish-at-the-heart-of-the-food-system/ for the in-depth read on what has Saving Seafood angry. 

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Setting the Record Straight on Menhaden

Limn Magazine's Online Article
Presents Unfounded Claims and Opinions -
Misrepresents the Menhaden Fishery and the Species' Ecology

WASHINGTON (Saving Seafood) -- February 28, 2014 -- "The Fish at the Heart of the Food System," by Alison Fairbrother and David Schliefer, published on the online magazine Limn and re-published on Gizmodo, contains mischaracterizations and disproven information regarding menhaden. Starting with its hyperbolic title--there is no scientific consensus that any one species is at the heart of the "food system"--much of the article compensates for a lack of scientific evidence by depicting refuted theories or personal opinions as proven fact. While this makes for a compelling narrative, it misrepresents the species and the related fishery.

The article bears the fingerprints of co-authorship. Ms. Fairbrother, of the Public Trust Project, has written extensively on menhaden in the past, and Mr. Schleifer, a healthcare researcher and writer at Public Agenda, frequently covers food science and health issues. While many of the nutritional portions contain citations and references, the fisheries portions do not indicate the source of much of the material. Upon examination, a number of these claims prove unfounded.

Saving Seafood has responded repeatedly to omissions and misinterpretations in previous articles about menhaden written by Ms. Fairbrother. Links and details for these past responses can be found at the end of this article.

Several inaccurate claims about menhaden that have appeared in previous writings by Ms. Fairbrother, and are repeated in this most recent article, include:

"...menhaden fishing destabilizes ecosystems...Today, many striped bass in the Chesapeake Bay are afflicted with mycobacteriosis, a previously rare lesion-causing disease linked to malnutrition."

Mycobacteriosis (or "myco") is widespread in Chesapeake Bay striped bass, with some estimates suggesting as much as 76 percent of the population is afflicted. Striped bass is a highly valued recreational species, and unsurprisingly, many fisheries scientists have investigated the cause of this disease. But despite what is suggested in the Limn piece, and what Ms. Fairbrother has stated in her previous work, there is no consensus on its source. While malnutrition is often a symptom of myco, a number of widespread environmental factors that are present in the Chesapeake Bay and severely impact the Bay's health are also closely linked to the disease. However, there is no mention of any of these other contributing causes in the article. In discussing its potential causes, Maryland Sea Grant clearly states, "hypoxia and habitat degradation may promote disease such as mycobacteriosis."

Evidence of mycobacteriosis in striped bass dates back to 1984, a time when menhaden stocks were near peak levels. And it is well documented that striped bass and menhaden have cyclical but inverse patterns of high and low population levels and are not abundant at the same time. Yet, all these factors are ignored in the Limn article, which presents an unreasonably simple and deceptive argument that supports a seemingly predetermined point.

"Until recently, this massive operation and its products were almost entirely unregulated, despite a substantial ecological impact."

From 2006 until last April, the Chesapeake Bay menhaden reduction fishery, representing the majority of East Coast menhaden fishing, was regulated by an annual cap limit. Last May, a coast-wide quota cut was implemented in the Atlantic commercial menhaden fishery.

Though the authors state that menhaden fishing has had a "deep ecological impact," they do not substantiate this serious claim. In fact, menhaden research repeatedly shows that the opposite is more likely. On its Chesapeake Bay website, the National Oceanic and Atmospheric Administration (NOAA), the highest ranking regulatory body overseeing the management of U.S. fisheries, states "menhaden recruitment appears to be independent of fishing mortality and spawning stock biomass, indicating environmental factors may be the defining factor in the production of good year classes."

The most popular method used to catch menhaden, purse seine nets, is also considered one of the world's "most selective and effective" in terms of bycatch "and has little to no effect on habitat," according to NOAA. Both the Atlantic and Gulf menhaden fisheries have less than one percent bycatch, and a 1992 study in Virginia estimated the percentage to be as low as 0.21 percent.

"The menhaden population has declined nearly 90 percent from the time when humans first began harvesting menhaden from Atlantic coastal and estuarine waters."

Without a citation it is unclear how this statistic was calculated. It is also unclear how an accurate population size for an historic, pre-colonial menhaden stock was established. The authors appear to be using the commonly cited statistic developed by the Pew Environment Group that menhaden numbers have "plummeted by 90 percent" in recent years, but Ms. Fairbrother should already know that this statistic was deemed mostly false by the Pulitzer Prize winning investigative group PolitiFact, as Saving Seafood has responded to her use of this claim multiple times. When looking into the Pew statistic, PolitiFact determined that the data points used to reach this number were cherry-picked, noting that if "you want to claim a 90-percent drop, you have to compare the 2008 population to a very specific -- and very exceptional -- year, 1982." The 90 percent drop allegation does not accurately represent the stock's current and historical levels. As PolitiFact observed, "the statement contains some element of truth but ignores critical facts that would give a different impression."

A similar claim later appears in the article:

"In 2009, fisheries scientists reported that the Atlantic menhaden population had shrunk to less than 10 percent of its original size."

Again, because there is no citation it is unclear which fisheries scientists are claimed to have reported this information. There is also no way to gain insight into how these scientists calculated the "original size" of the stock. This vague term could be used to represent menhaden populations at many points in time. It could mean an untouched menhaden stock in the 1600s, or a stock that early European settlers encountered. It could even represent any number of menhaden population levels in the 20th Century. Without context of when the researchers chose to label the stock "original," this is a meaningless term.

There is a strong possibility that the statistic mistakenly conflates the fishery management term, "theoretically unfished population," with the notion of an "original stock." One of many calculations used to set fishing quotas is the percentage of how many fish in the stock are able to spawn after fishing occurs, versus how many would be able to spawn in a stock that didn't experience any fishing, i.e. a theoretically unfished population. A theoretically unfished population is not the same as a virgin stock from an historical era before human settlement and fishing -- it is a current theoretical maximum that, for menhaden, constantly changes depending on a variety of environmental factors.

In 2009, scientists from the Atlantic States Marine Fisheries Commission (ASMFC), an organization that coordinates management of fisheries in state waters among Atlantic states, including coastal menhaden fisheries, determined this value point between "fished" and "unfished" stocks was at 10 percent. This is lower than the 15 percent and 20 percent limit and target reference points previously established by the Commission. Because of multiple flaws in data, however, this assessment failed to be considered viable for management use. If this is indeed how the statistic was developed, it is far from accurate.

The Limn article also features several other claims that, though stated as fact, are actually unproven.

The article states that in the mid-2000s, menhaden numbers were so low that "striped bass were preying on small weakfish and substantially reducing their population." But this claim is asserted without any scientific attribution or recognition from fishery managers. Far from an established fact, eight years ago this idea was proposed to the ASMFC as one of several hypotheses to explain an observed decline in weakfish. Recently, when asked if striped bass predation is affecting weakfish due to low levels of menhaden, the Weakfish Technical Committee Chair and the Fisheries Management Plan Coordinator of the ASMFC told Saving Seafood that "there is no scientific evidence to substantiate that claim."

The Delaware Division of Fish and Wildlife reached similar conclusions through independent research regarding striped bass and weakfish. Since 2006, the Division's scientists have investigated striped bass predation and its possible effects on fish populations. They have looked closely at weakfish, but repeatedly found that predation has only occurred at low levels, and in some years was almost nonexistent. This study is still ongoing, but the researchers agree that "there is no conclusive link" to attribute a decline in weakfish to striped bass predation.

Qualitative judgments, not science, are also used throughout the piece to characterize the ecological role of menhaden. The authors stamp menhaden "a lynchpin of the oceanic foodchain," and describe the fish as being "at the heart of the food system." In the past, Ms. Fairbrother has argued that stricter catch regulations on the fish "may have saved the Atlantic Ocean." But, nothing supports the idea that any one fish in the Atlantic ecosystem is most important.

Lastly, the story references a study from the Lenfest Forage Fish Task Force. That study highlights the value of ecosystem-based fisheries management, an approach largely agreed upon by conservationists, fisheries managers, and fishermen alike. But the Limn article references, in particular, a controversial statistic from the Lenfest report, which claimed that the economic value of leaving "forage fish" (a disputed term that includes a number of small fish with a similar ecological role to menhaden) in the ocean is double the economic value of harvesting these species. Saving Seafood has dissected this claim in great detail - the analysis can be found here. The Lenfest study is based on broad assumptions that do not consider the diversity and behavioral differences of the species united under the umbrella term "forage fish." Substantial research on these species indicates that the inferences in this study will likely not be true for every fish and ecosystem.

The waters of the Atlantic house complex ecosystems with countless interactions between different species and their environments. This can make drawing firm conclusions with certainty about these species difficult. The Limn article is presented as an informative scientific feature, but many of its claims lack objectivity and accuracy. While scientists and managers work to more clearly understand these Atlantic ecosystems, misrepresentations of their research can cloud the waters, impeding public understanding of important issues and meaningful progress to advance scientifically informed and responsible fisheries management.


For More Information:

Saving Seafood has previously responded to inaccurate and misleading claims about menhaden in Ms. Fairbrother's work. Two examples are detailed below:

Another article by Ms. Fairbrother featuring a hyperbolic headline, "A Fish Story: How an Angler and Two Government Bureaucrats May Have Saved the Atlantic Ocean," published on May 10, 2012 in Washington Monthly, inaccurately described how reference points were determined for menhaden management, and claimed that a lack of menhaden caused the spread of the bacterial infection mycobacteriosis in the Chesapeake Bay's striped bass population. These claims ignored a review of scientific literature in The Veterinary Journal concluding that there is currently no consensus about the primary cause of mycobacteriosis.

Read Saving Seafood's analysis here.

In a September 2012 interview with GovLoop, Ms. Fairbrother alleged that, "the menhaden population had declined 88 percent in 25 years," using cherry-picked data comparing one of the highest recorded years of menhaden with one of the lowest. When a more complete time series (dating back to the 1950s) is examined, the menhaden population shows fluctuations between highs, such as those seen in the late 1970s and early 1980s, and the current population, which is at levels similar to those seen in the 1960s. These fluctuations are more likely the result of favorable environmental conditions than a reduction in fishing activity.

Read Saving Seafood's analysis here.

References:

Atlantic States Marine Fisheries Commission, "Weakfish: Stock Status," http://www.asmfc.org/species/weakfish

Austin, H.M., J.E. Kirkley, and J. Lucy, 1994. "By-catch and the fishery for Atlantic menhaden, Brevoortia tyrannus in the Mid-Atlantic Bight: An assessment of the nature and extent of by-catch." Virginia Sea Grant Marine Advisory Program, #103-260-955. http://web.vims.edu/GreyLit/VIMS/MRA53.pdf?svr=www

Delaware Division of Fish and Wildlife, "Striped Bass Food Habits Project," May 2006. http://www.dnrec.delaware.gov/fw/SiteCollectionDocuments/FW%20Galle...

Horst, Jerald, "Everybody Eats Pogies: Industry is close to perfect fishery," Louisiana Sportsman. September 4, 2013. http://www.louisianasportsman.com/details.php?id=5576&utm_sourc...

NOAA Fisheries, "Menhaden Fish Facts," Chesapeake Bay Office. January 2012. http://chesapeakebay.noaa.gov/fish-facts/menhaden

"Pew Environment Group says the Atlantic menhaden population has declined by 90 percent in recent years," PolitiFact. December 14, 2012.
http://www.politifact.com/rhode-island/statements/2012/dec/14/pew-e...

U.S. Fish and Wildlife Service, "Osprey," Chesapeake Bay Field Office. January 28, 2011 http://www.fws.gov/chesapeakebay/osprey.html
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