Sardines And Other Plankton Feeding Forage Fish Decline
The desperate state of forage fish is resulting in the Pacific Fishery Management Council making radical new ecosystem ocean pasture management recommendations.
Tiny forage fish commonly seen in vast schools fish are dependent on a lot of plankton blooming within their ocean pastures. When the forage fish are healthy and abundant they in turn fill the bellies of all marine life especially salmon, tuna, sea lions and sea birds. When they are in decline it means the whole system is in dire straits.
Plankton eating forage fish make up more than a third of global seafood harvests, but very little of this harvest is destined for the human dinner table. Globally, 90% of forage fish that is caught is processed into fish-meal, to be used as protein-rich feed for livestock and pet food.
Following many years of observed steady collapse of the all important sardine stocks and widespread forage fish decline the Pacific Fishery Management Council endorsed a sardine stock estimate late last year of only 378,000 metric tons, just a quarter of the 2006 peak sardine stock of 1.4 million metric tons.
As a result of this decline the fishery management council is working to develop a new ecosystem-based ocean pasture management plan that recognizes the foundational and keystone role of forage fish and the plankton that they feed on in the Pacific marine food web.
Fossil and historical records have revealed that sardine abundance fluctuates widely on a sixty-year cycle, appearing to coincide with “warm” and “cold” periods in the North Pacific that alternately favor northern sardines vs. more southerly anchovies. In a seemingly counter-intuitive ocean reality sardines actually diminish when the Pacific shifts to a colder regime. John Steinbeck wrote of this in his famous book Cannery Row.
There is a common misconception about colder ocean waters that being that colder waters are more productive. This mistaken idea derives from observations of cold upwelling coastal ocean waters which indeed bring deep nutrients to the surface. While it is true these upwelling waters are more productive they are a small part of the giant ocean.
The ocean is vast and it makes no sense to define the vast ocean based on a small part of it. It’s as if we described a pasture in Vermont as being typical of a pasture in Arizona, they simply are not at all the same ecology simply because they are both part of “North America.”
This ocean cooling tied to enhanced productivity is not what is happening in what is described as N. Pacific decadal oscillation. The decadal cooling phase is a top down cooling that is reducing ocean pasture productivity as clearly evidenced by the collapse of the sardines and forage fish primary grazers of the ocean pastures. Those forage fish are a keystone group that are broadly integrated and accurate indicators of ocean health. The “ocean” is a vast complex ecosystem comprised of many ocean pastures and ecosystems, it’s not just one simple “the ocean.”
In a 2012 report, “Cold oceanographic regime with high exploitation rates in the Northeast Pacific forecasts a collapse of the sardine stock” published in the Proceedings of the National Academy of Science, fisheries researchers Juan Zwolinski and David Demer showed that cold Pacific environmental conditions today mirror the circumstances surrounding a dramatic sardine crash in the late 1940s, suggested we would be experiencing a similar natural decline.
The present collapsing numbers of sardines confirms this. As a result of the current sardine and forage fish decline, the fisheries council has drastically curtailed the annual catch limit for the 2014 season to 23,000 metric tons, down 65 percent from the 2013 season.
Mike Okoniewski, co-chair of the council’s Coastal Pelagic Species Advisory Sub-Panel, worries that the decline may continue until the entire population of sardines sinks below 150,000 metric tons, at which point all sardine fishing would have to be halted.
The Ecosystem Trophic Role
At its April 2014 meeting, the council considered several alternatives for protection of unmanaged forage fish within four established management plans: salmon, groundfish (rockfish, flounder, lingcod), highly migratory species (tuna, marlin, sharks) and coastal pelagic species (sardines, anchovies, mackerel, squid).
The “Ecosystem Trophic Role Pathway” emerged as a preferred alternative, in recognition of the critical role of forage fish as a food source within the broader marine ecosystem.
This is a dramatic departure from traditional fishery management, in which each species is considered in isolation. The ecosystem-based management approach reflects recommendations of the Lenfest Forage Fish Task Force, and is supported by environmental groups as well as the National Oceanic and Atmospheric Administration.
The council will conduct further scientific and economic analysis of alternatives, draft amendments to current management plans and seek public comment over the remainder of this year. In late 2014 or early 2015, the council will make recommendations to the National Marine Fisheries Service and the Secretary of Commerce, which bear responsibility for implementing and enforcing regulations.
We can only hope they will fall into line behind an ocean pasture management approach that considers need to steward the carrying capacity of ocean pastures as the key role in ocean fish management.
Fisheries management has almost exclusively been a reactive tool, developing responses to try to fix problems after the damage has been done – management by crisis, usually resulting in round robin like process where some interest group, the political choice of the moment, is forced to take an economic hit.
“There is a general consensus that we need to be proactive,” says Gway Kirchner, Marine Fishery Management Section Manager for the Oregon Department of Fish and Wildlife. “I’ve never been part of something where we had almost complete agreement across divergent groups of people.”
Okoniewski, who has worked in the fishing industry for four decades, acknowledges that scientists and the fishing community don’t always see eye to eye. But he expresses optimism about becoming stewards of ocean pastures via the council’s efforts: “Having healthy ecosystems is a goal environmental groups and fishermen agree on.”
Shively agrees. “Every single one of those iconic species we treasure – salmon, whales, sharks, sea birds – relies on forage fish,” he says. “A healthy ocean means there’s plenty of forage fish to be eaten. That’s what we need to protect.”
Ocean Pasture Restoration And Stewardship Is A Better Solution
We have demonstrated that a far more practical solution to ocean ecosystem management is to become active stewards of our ocean pastures. While there is some sense in the science of ocean cycles basing ocean ecosystem management on only those “natural cycles” is like basing response to climate change only on a natural cycle stance which ignores mans involvement in global change.
The ocean pasture and sardine collapse is also clearly tied to high and rising CO2 impacts which results in deprivation of the ocean of vital mineral micro-nutrients. When we restore ocean pastures by replenishing these vital nutrients that we have denied those pasture they return to a state of health and abundance of a century ago and the role of decadal warming and cooling cycles becomes of much less significance.
Here’s a couple links to posts to get you started on the story of ocean pastures, how they function (or fail), and how we can bring them back to life and bring the fish back as well.