WASHINGTON — March 30, 2012 — Fishing for herring, anchovy, and other “forage fish” in general should be cut in half globally to account for their critical role as food for larger species, recommends an expert group of marine scientists in a report released today. The Lenfest Forage Fish Task Force conducted the most comprehensive worldwide analysis of the science and management of forage fish populations to date. Its report, “Little Fish, Big Impact: Managing a crucial link in ocean food webs,” concluded that in most ecosystems at least twice as many of these species should be left in the ocean as conventional practice.
A thriving marine ecosystem relies on plenty of forage fish. These small schooling fish are a crucial link in ocean food webs because they eat tiny plants and animals, called plankton, and are preyed upon by animals such as penguins, whales, seals, puffins, and dolphins. They are primary food sources for many commercially and recreationally valuable fish found around North America, such as salmon, tuna, striped bass, and cod. The task force estimated that, globally, forage fish are twice as valuable in the water as in a net—contributing US$11.3 billion by serving as food for other commercially important fish. This is more than double the US$5.6 billion they generate as direct catch.
These species play a growing role in the everyday lives of industrialized nations. Their demand in recent decades has greatly increased for use as fish meal and fish oil to feed farmed fish, pigs, and chickens that people consume on a regular basis. Fish oil is also used in nutritional supplements for humans.
“Traditionally we have been managing fisheries for forage species in a manner that cannot sustain the food webs, or some of the industries, they support,” says Dr. Ellen K. Pikitch of the Institute for Ocean Conservation Science at Stony Brook University, who convened and led the Lenfest Forage Fish Task Force. “As three-fourths of marine ecosystems in our study have predators highly dependent on forage fish, it is economically and biologically imperative that we develop smarter management for these small but significant species.”
Small schooling fish are an important part of the ecosystem on both coasts of North America. Many marketable species on the Pacific coast, such as salmon, lingcod, Pacific hake, Pacific halibut, and spiny dogfish, feed on them. A large number of seabird species relies on them as well, and research shows that the breeding success of the federally endan¬gered California least tern may depend on the availability of local anchovy populations. On the eastern seaboard, more menhaden are caught (by weight) than any other fish off the Atlantic coast. Taking out excessive amounts, however, means less food for tuna, bluefish, and striped bass ― as well as whales, dolphins, and seabirds – and affects fisheries and tourism industries from Maine to Florida.
Read a summary of the report here.
Analysis: The Lenfest Forage Fish Task Force focuses on many different types of forage fish, among them Atlantic menhaden (pgs. 42-43 of the full report). On menhaden, the Task Force writes, “Menhaden abundance within the [Chesapeake] bay itself has not been estimated, but heavy fishing has led to concerns by recreational fishermen, managers, and the public regarding localized depletion of menhaden and their attendant losses of ecosystem services as prey and filterers.”
There is currently no evidence that localized depletion is occurring or has occurred in the past. Given the nature of the menhaden population, which migrates coast-wide and moves in and out of the Chesapeake Bay on a frequent basis, it is unlikely that localized depletion would occur. While a severe depletion of adult menhaden would likely limit the number of menhaden entering Chesapeake Bay, this would result in a coast-wide rather than local depletion.
There is other evidence to suggest that localized depletion may not be as big a problem as assumed. The Lenfest Task Force writes, “the once-depleted striped bass stock was rebuilt, and piscivorous birds, such as osprey and bald eagles, have rebounded and are abundant.” Since all of these species feed on menhaden, among several other species of fish, their recovery does not suggest a lack of forage.
The Task Force also concludes that the current level of fishing is insufficient for maintaining their recommended levels of forage fish. They write, “more conservative management by the ASMFC is needed, because the most recent stock assessments indicate that fishing is a bigger factor than previously thought (ASMFC 2010) and there is no management mechanism to reduce fishing mortality to appropriate levels.”
However, the Atlantic States Marine Fisheries Commission (ASMFC), in its 2010 stock assessment report, concluded that the size of the menhaden stock is largely due to factors outside of the commercial fishery. They write, “past performance of Atlantic menhaden suggests it has gone from periods of low recruitment and fecundity to periods with high recruitment and fecundity, while sustaining moderate to high landings. In recent years the fishery has experienced some of the lowest landings on record, yet recruitment remains near the 25th percentile. This outcome may be indicative of a stock with an undefined production function (e.g. stock-recruitment curve), whose population fluctuations are almost entirely driven by non-fishery sources” (pg. 91).
If fluctuations in the menhaden population are driven mostly by non-fishery sources, then reducing the level of the commercial harvest to the levels the task force recommends would not be guaranteed to have the desired effect. It would have little impact on the size of the menhaden population, and environmental factors would continue to play a larger role in influencing menhaden spawning.
The Task Force’s reference to “no management mechanism to reduce fishing mortality to appropriate levels” is not correct. The ASMFC has a very well defined management mechanism to establish harvest regulations when they are deemed necessary. While no measures are currently in place, the ASMFC has determined that management measures are needed and has initiated a process to implement measures that would reduce the Atlantic menhaden harvest. This process began following the discovery that slight overfishing occurred in 2008 at 0.4% above the limit reference point.