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Catching a Share of River Herring
Two species of fish that were once scooped up by the millions of pounds as they migrated from the sea up freshwater streams are today at risk of population collapse

EVERY YEAR at the end of May on the Maine coast, an estimated 150,000 alewives navigate up the Damariscotta River estuary and into the Great Salt Bay before “running” up a 200-year-old stone fish ladder that takes them into Damariscotta Lake to spawn.

The annual run of river herring, which in some rivers includes both alewives and blueback herring, is a ritual that dates back thousands of years. Damariscotta Mills residents have depended upon them for centuries, and today celebrate the return of these anadromous fish as they navigate from salt to freshwater to breed.

  blue herring
  Alewife illustration by Ted Walke.
Illustration courtesy of Pa. Fish & Boat Commission.
  blue herring
  Blueback Herring by Ted Walke.
Illustration courtesy of Pa. Fish & Boat Commission.

With waters roiling around multitudes of silvery, foot-long fish as they surge upstream, one would think there were more than enough river herring to go around. But alewives and blueback herring are listed as “Species of Concern” by the National Oceanic and Atmospheric Administration (NOAA) and, says research scientist Jamie Cournane of the EOS Ocean Process Analysis Laboratory (OPAL), “are considered to be severely depleted.”

Compounding the concern over river herring stock status is the fact that they are an important forage species for large predatory fish like Atlantic cod, haddock, and bluefin tuna, as well as protected marine mammals, and seabirds. Thus, river herring restoration is important for rebuilding coastal stocks of popular market and recreational species, including iconic fish like cod, which feed on them seasonally.

To that end, commencing in September of this year, Cournane will work through the end of 2012 to develop a state-of-the-art fisheries stock assessment model and conduct workshops with fishermen to help restore the depleted East Coast population of river herring. The work, in conjunction with co-investigator Christopher Glass, director of OPAL and the Northeast Consortium, is the result of a $142,700 grant from the National Fish and Wildlife Foundation under its Fisheries Innovation Fund.

Jamie Cournane
Photo by UNH Photo Services.

According to Cournane, who conducted related river herring research for her post-doctoral work with the Environmental Defense Fund, the upcoming project involves two objectives: improve the basic science concerning river herring to determine as accurately as possible the entire East Coast population; and, through a series of workshops with fishermen, come up with the best means of developing a fisheries management program to help restore river herring.

"We have no idea how many river herring there are today, but we do know that many river herring runs have declined along the East Coast to such a degree that collapse of the coast-wide stock is feared to be underway,” Cournane says.

One need only look at historical catch data to know that “collapse” is no hyperbole. Since reaching a peak of almost 37 million pounds in New England in 1958, commercial landings of river herring have declined 98 percent to 741,000 pounds in 2007 despite improvements in water quality, restoration of fish passageways, and state-specific landings moratoriums. At 2007 prices, the 1958 catch would have been worth $7,460,000.

River herring undertake extensive migrations, spawning in fresh and brackish water, before returning to the ocean where they spend the majority of their lives. With such a life-history strategy, they encounter numerous threats in their riverine, estuarine, and oceanic habitat. Along the New England coast, damming greatly reduced the historical extent of river herring populations and their associated distributions in freshwater. Many recent and current dam removal and water quality improvement projects in the region hope to undo more than 100 years of habitat loss for these species.

Today, another important impact is bycatch – in which river herring are unintentionally caught by oceanic fisheries. Both the New England Fishery Management Council (NEFMC) and the Mid-Atlantic Fishery Management Council (MAFMC) are exploring options to address river herring bycatch in these fisheries

Cournane’s most recent work has involved helping NEFMC fisheries managers figure out possible options to address river herring bycatch in federal waters from three to 200 nautical miles off the U.S. coast.

  The head of the Squamscott River in Exeter, N.H. This tidal river leads north to Great Bay and is a site for the annual alewife runs upriver to freshwater spawning grounds.
Photo by Jamie Cournane, UNH-OPAL.

It’s an important point; beginning in 2012, a moratorium on landing river herring within three nautical miles will be put in place for all but a few select portions of the East Coast (including sections of Maine and New Hampshire). However, open ocean fishing in federal waters, where bycatch occurs, will not be affected by the moratorium.

“This presents a challenge,” Cournane notes, “because outside state waters bycatch of river herring remains unmitigated.”

Options Cournane has discussed with the NEFMC as part of her post-doc work include increased monitoring, catch caps, closed areas, and "move-along" avoidance strategies to address river herring bycatch. In move-along avoidance, herring fishermen cease fishing in areas when high river herring bycatch is encountered."

A conceptual model or “thought experiment”
The first phase of Cournane and Glass’s study will involve pooling historical catch data on river herring to “hindcast” coast-wide populations, which will help establish current population numbers vis-à-vis today’s greatly diminished catch. These estimates will eventually become part of the conceptual model they construct for a comprehensive fisheries management strategy. The model will also contain data derived from workshops held with fishermen to get their perspectives on a potential fisheries management plan for river herring.

This conceptual management plan will likely involve a “catch share” system, an approach used extensively in other fisheries (such a system was put in place last year for New England groundfish which include cod, haddock, and others) but never for an anadromous species like river herring, for which migration from open ocean to freshwater lakes and streams makes jurisdictional and geographic management particularly challenging.

The catch share approach is very much in line with the reauthorization of the federal Magnuson-Stevens Fishery Conservation and Management Act, which established accountability and limits on catches and has as its charge the end of overfishing.

With respect to river herring and the work ahead, Cournane is fully aware of the inherent difficulties of placing a moratorium on inshore fishermen while the oceanic fisheries and their bycatch of river herring continues unabated.

“It’s hard to reconcile, but our study will provide a baseline. We’ll be able to say ‘here’s where we are right now, here’s our best estimate of the coast-wide river herring population, and here’s where fishermen stand on the issue.’ From these outcomes, we’ll frame possible management options in our conceptual model.”

Cournane remains optimistic for the restoration of river herring populations and hopes that "our work will add an important missing piece to ongoing restoration and recovery efforts of these resilient species.”

Editor’s note: Many thanks to historical marine ecologists William Leavenworth and Karen Alexander of OPAL for their input and review on the historical and cultural aspects of river herring for this story.

by David Sims, Science Writer, Institute for the Study of Earth, Oceans, and Space. Published in Summer 2011 issue of EOS Spheres.