Scientific studies show that menhaden reproduction is far more influenced by environmental factors—weather, for instance—than by commercial harvest, said Joseph Smith, a fisheries biologist at the National Marine Fisheries Services and member of the technical committee that wrote the menhaden assessment.
"Intuitively, it makes sense" that less fishing means more menhaden, Smith said. "But it doesn't work that way. Based on years of data, "there doesn’t seem to be a very good relationship between the number of spawners and the number of juveniles."
Despite the scientists' claims, environmental and recreational fishing groups are calling for reduction of commercial menhaden fishing, a move they call critical to the health of the Chesapeake Bay and to menhaden predators, such as striped bass and sea birds.
by JONATHAN HEMMERDINGER
Special to Saving Seafood
WASHINGTON – May 12, 2011 — The debate over the health of Atlantic menhaden stocks only intensified after the May 6 release of a stock assessment report by the Atlantic States Marine Fisheries Commission.
In its report, ASMFC, a multi-state agency governing coastal fish species, determined that the menhaden fishery "is not overfished, nor is it experiencing overfishing." In addition, ASMFC said menhaden reproduction "appears to be adequate to produce the target number of eggs."
But the agency cautioned that menhaden fishing is "close" to the maximum rate at which the species can still replace itself and that the population of young menhaden has been low for decades. The report also said the abundance of menhaden has declined "steadily" since the early 1980s and recruitment (the number of surviving offspring) is "relatively low."
The report was welcome to the menhaden fishing industry, particularly Omega Protein, which "reduces" menhaden into omega-3 rich fish oil and fishmeal used in livestock and aquaculture feed.among other products.
“The findings of this stock assessment validate that Omega Protein and other menhaden fishermen have been fishing in a manner that does not negatively impact the sustainability of the menhaden fishery,” said Ron Lukens, Omega's senior fisheries biologist and former assistant director of the Gulf States Marine Fisheries Commission.
Omega, a publicly traded firm with 2008 revenue of $177 million, operates the last remaining menhaden reduction plant on the East Coast, in Reedville, Va., and a fleet of menhaden fishing boats, which haul the oily fish out of the Atlantic Ocean and the Chesapeake Bay.
Environmental and recreational fishing groups read the report differently, however. They say the agency's finding indicate the fish are in trouble.
"Abundance declines year after year after year," said Charlie Hutchinson, who writes a column for the Maryland Saltwater Sportfishermen's Association. "At what point do you reach a situation where [the Bay] can't recover?"
Menhaden stocks are “currently at the lowest stock level ever recorded and the recent stock assessment indicated overfishing has probably occurred in something like 33 out of the past 35 years,” said Greenpeace ocean campaigner Phil Kline in an email. “The Greenpeace position is to end the reduction fishery, keep harvest caps on the bait fishery to allow the population to rebuild."
Ending the reduction fishery would put 300 Virginians on the unemployment line.
Fishing may not be to blame
Scientific studies show that menhaden reproduction is far more influenced by environmental factors—weather, for instance—than by commercial harvest, said Joseph Smith, a fisheries biologist at the National Marine Fisheries Services and member of the technical committee that wrote the menhaden assessment.
"Intuitively, it makes sense" that less fishing means more menhaden, Smith said. "But it doesn't work that way. Based on years of data, "there doesn’t seem to be a very good relationship between the number of spawners and the number of juveniles."
He did say, however, that the agency found that fishing mortality- the rate at which fish die from fishing, not from natural causes—is below problem levels, "but only a bit." And because the science isn't perfect, he said there's a chance overfishing has occurred.
"The probability that [we] might have gone over … brings a lot of consternation to some people," Smith said.
Lukens at Omega said his company's fishing has "nothing to do" with poor menhaden recruitment. "Menhaden are one of the most prolific spawners on earth," he said. "[They] produce significantly more eggs than most fish … and the thing that impacts recruitment is environmental conditions."
Lukens said Omega is taking heat because, unlike environmental conditions, fishing can be regulated. "People want to control what they can control," he said.
ASMFC calls for new “reference points”
Based on the report, ASMFC on Wednesday asked the technical committee—a body composed of some dozen scientists and biologists—to develop new scientific "reference points" defining overfishing. The goal, said an ASMFC media release: "to increase protection of the spawning stock."
Omega's opponents say new reference points are critical and long overdue and could prove the species is overfished. The current reference points, they say, mask overfishing.
“Given the current reference points [menhaden are] not classed as overfished in [scientific] models but it is without question that serious ecosystem overfishing is still occurring,” said Greenpeace ocean campaigner Phil Kline in an email.
Hutchinson sees progress. "There is a shift in the mood of the commissioners. No one fell asleep. No [one was] fiddling with their computers. For the first time yesterday, [the reference points were] seriously challenged."
Greenpeace and other groups say heavy menhaden landings are hurting the health of the already ailing Chesapeake Bay, the largest estuary in the United States, and impacting species such as striped bass and sea birds, which eat menhaden. And they say the agency’s scientific model doesn’t adequately account for the dietary needs of species dependent on menhaden.
ASMFC should “ask the striped bass, weakfish, whales, bluefin [tuna], birds and other animals that depend on menhaden what their dietary needs are,” said Kline.
“Allocate fish to them first, not to Omega,” he added.
That strategy, however, would have economic and social implications. Omega's Reedville, Va., plant has some 300 employees and contributes $48 million to the economy, said spokesperson Ben Landry.
Role of striped bass
Jim Price, executive director of the Chesapeake Bay Ecological Foundation, has been studying the stomach contents of striped bass since the 1970s. Although some of the bass Price examines he catches himself, most come from charter boats in Maryland's mid-Chesapeake Bay region.
In an interview, Price, who is licensed by the state of Maryland to collect striped bass for scientific purposes and provides his data to the Maryland Department of Natural Resources, said scientists largely don’t understand the interaction between striped bass and menhaden.
“No one has done a thorough job of examining large striped bass,” said Price. There have only been “piecemeal studies” and the agency has underestimated the impact of natural predators.
Price said his studies indicate that menhaden are “crucial” to striped bass, accounting for nearly all of the diet of large bass during the winter and 75 percent of their diet year round. And he said low menhaden recruitment has caused “skinnier, thinning and more unhealthy” bass.
But Price said the decline in menhaden stocks coincided with the increase in striped bass stocks, which grew significantly during 1990s after the implementation of strict fishing restrictions. Striped bass, he said, have had “more of an impact” on menhaden stocks than the fishing industry.
“I am not saying they are not overfishing [menhaden],” but a lot of the striped bass problems are “not because of menhaden fishing,” he said. ASMFC is “underestimating natural mortality by predation."
Price said that to protect menhaden regulators may want to consider encouraging more striped bass harvest by reducing the striped bass size limit from 18 inches to 14 inches.
That approach, he said, would “get food supply in balance with prey.”
Hutchinson of MSSA doesn’t support the idea of increased fishing for striped bass. Not only are bass a "poster boy" for successful fisheries management, but the species support the bay's economy, he said.
Marina, bait and tackle shops, charter boat crews employ more workers than the Reedville, Va., Omega processing plant, he said.
Despite criticism, Smith at ASMFC said the agency’s models do account for predators such as striped bass.
"Some detractors of the assessments say [we] are not incorporating predation. We do,” said Smith. “It’s a pretty advanced assessment incorporating multiple species … bluefish, striped bass and weakfish.”
And according to an ASMFC assessment overview, the agency's analysis "explicitly modeled predator-prey interactions among menhaden, striped bass, weakfish, bluefish and several other prey species from Maine to North Carolina."