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Update on River Herring

Alewife and blueback herring are two species that are collectively known as river herring. Coast-wide the relative abundance of the alewife population appears to be increasing while the blueback herring population appears to be stable. On a local scale, we’ve seen large increases in river herring abundance on some rivers. This is due to ongoing restoration and conservation efforts along the east coast. 

On August 9 we determined that neither species is threatened or endangered so listing under the Federal Endangered Species Act is not warranted at this time. However, we still have concerns about the status and threats to these species. As a result, both species are still included on our Species of Concern list. Additional data are needed to help us better understand the abundance of specific stocks throughout each species’ range.  We also need to learn more about the genetic structure of both species, the population level effects of remaining dams, the ocean migratory phase of these species, and the effects of climate change on both species in their freshwater habitats.

More recently, during their October council meeting, the Mid-Atlantic Fishery Management Council announced plans to form an Interagency Working Group to address threats on River Herring and Shad. This is welcome news and a wonderful complement to our own efforts in conjunction with the Atlantic States Marine Fisheries Commission. Having these dedicated resources will improve the chances of successfully restoring these species. We plan to continue to work with our federal partners to maximize limited resources and identify ways to complement each other's ongoing efforts. 

To develop a river herring conservation plan we plan to work collaboratively with our federal, state, Tribal, academic and environmental community partners to collect additional data and information to fill in key data gaps. We also plan to revisit the listing determination within the next five years based on any new information we collect.

Conservation Plan Development

We provided funding to the Atlantic States Marine Fisheries Commission to assist us in developing a long-term and dynamic conservation plan. Through the plan, we will establish key conservation efforts to benefit river herring throughout their entire range, as well as identify and fund some priority research needs. A Technical Expert Working Group will be convened to help with plan development. 

With input from the working group, we will consider previously identified threats and research and conservation efforts and describe a coordinated and prioritized coastwide approach to address data gaps. We will attempt to quantify the impact of ongoing restoration and conservation efforts. We will also consider the benefits of new fisheries management measures being considered such as catch caps in two federal fisheries. We will review any new information produced from ongoing scientific studies on genetic analyses, ocean migration patterns, and climate change impacts completed in the next several years. And, we will assess whether higher counts of river herring in many rivers along the coast in the last two years represent sustained trends.

The end products of this work will be to identify significant threats to river herring and then create a list of conservation actions to help improve the health of both species populations throughout their entire range.  Working with our partners and using the funds we have already made available, we will implement some of these conservation actions and fund critical research as resources permit. The working group will further assist us by monitoring and tracking  progress of conservation efforts and recommending changes, new actions, and activities as needed.

At the same time, we will continue our restoration work to improve access to spawning habitats in rivers, streams, and lakes, which is critical for migratory, anadromous (spend portions of their lives in fresh and salt water) fish, like river herring.

Ongoing Habitat Restoration and Conservation Success

After access to fish ladders at two dams on the St. Croix River in Maine was restricted in 1995 and alewife couldn't reach nearly 98 percent of their historic spawning grounds, alewife populations plummeted—from 2.6 million in 1987 to 900 in 2002. With the removal of a wooden obstruction at the Grand Falls Dam in June 2013, herring will now be able to reach more than 50 percent of upstream lake habitat. The St. Croix River, which forms the border between Maine and New Brunswick, has the potential to become one of the largest alewife runs in the United States. This will benefit the Passamaquoddy people, Maine’s commercial fishing industry and fish and wildlife throughout the Gulf of Maine.

On the Penobscot River removal of two dams and installation of a fish passageway on a third dam is also expected to improve access. Fish will be able to reach the upstream river network and 39 lakes that once supported alewife. In total, about 93 percent of the historic habitat for blueback herring and around 31 percent of the historic habitat for alewife will become accessible, provided they can successfully pass remaining mainstem dams. In addition, NOAA Fisheries staff are continuing to work on integrated efforts to further increase access to the many key lake habitats for alewife on the Penobscot.

While large-scale projects have tremendous potential, some small-scale projects are already showing results! For instance, on the Acushnet River in Massachusetts, dams were removed or modified and nature-like fishways were constructed. The river herring return has gone from less than 300 fish in 2006 to over 6,000 herring in 2013. Removal of two dams in Sedgeunkedunk Stream in Maine allowed a small (few hundred) but growing river herring population to re-colonize Fields Pond within just one year of the dam removals. The re-colonization of Fields Pond occurred without any stocking. In 2010, a culvert located in East Lyme, CT which connects Bride Brook to Long Island Sound was enlarged. Recent numbers, including those for 2013 where they documented the run at over 360,000 fish, are significantly higher than the larger runs documented in the mid-1970s, which numbered around 125,000.

River herring species are critical to fully functioning marine, estuarine, and freshwater ecosystems. We will remain engaged, together with our partners in restoration and conservation work so that river herring populations can continue to grow.

For more information on the listing determination, conservation plan development or technical expert working group, call Kim Damon-Randall, Protected Resources Division, at (978) 282-8485 or e-mail her at

Information and updates also are available online at