Alewife Restoration – Part III

Citizens and Science Restoring Maine Alewives

by Bailey Bowden

Building on the town of Penobscot’s successful alewife restoration projects, which included the repair of two fishways at Wight and Pierce Ponds, the towns of Brooksville and Sedgwick have joined the effort to create a completely free-flowing Bagaduce River. That project could bring a quarter of a million alewives to the Bagaduce. The three towns working together on the project increases the chances of success. But coordination and rigorous science are key to achieving that success.

Increasing alewife capacity is needed in towns with a strong cultural connection to their local fisheries. However, these towns often need support when dealing with governance systems that were not created to engage with town government. Likewise some towns are not accustomed to engaging with complex science and policy issues.

The multi-town effort to restore the Bagaduce alewife is supported by several nonprofit organizations. Each brings its own unique resources and expertise to the project. The Maine Coast Heritage Trust (MCHT) took the lead with the fish passage project in Penobscot. The Maine Center for Coastal Fisheries (MCCF) has taken the lead role in alewife science, research and as a policy advisor for the Bagaduce River towns. The Bagaduce effort is central to MCCF’s vision for Maine’s coastal town’s connection to their fisheries and the opportunity to “fish forever.” These efforts involve towns and local stakeholders taking ownership of the research and management of their fisheries. This local involvement is referred to as co-management and is a concept at the heart of MCCF’s vision.

Alewife and other anadromous fish that spawn and rear in fresh water ponds, but spend their adult life at sea, are keystone species in the marine food webs.

Mike Thalhauser, a fisheries biologist with MCCF, has been a state fisheries manager. He has also worked with co-managing fisheries in Alaska. Thalhauser said, “The knowledge the folks in these towns possess about specific local streams, ponds and alewife runs is something that a statewide manager just can’t achieve at the level he or she is working. This is management by the right people at the right level. These towns are committed to their alewives.”

Maine law allows municipalities to manage their local alewife harvest if certain criteria are met. MCCF staff help organize volunteers who gathered the required data from Walker’s Pond in Brooksville and both Pierce’s and Wight’s ponds in Penobscot. The data are used to determine the health of each run and include length, weight, and sex. Age is determined by taking 15–20 scales from each of 100 fish in each water system. Like tree rings, alewife scales have rings that allow age to be determined by observing these rings as well as the annual growth patterns on them. Other important facts are gleaned from these samples, such as determining the number of times an individual fish has returned to spawn. Counting fish is, of course, also important. In 2017 the first count of Walker Pond alewife was successfully completed by volunteers and it found that over 135,000 fish had returned.

One important issue for the Bagaduce towns is a brief study conducted by the Maine Department of Marine Resources (DMR) in the early 1980s. It determined that the alewives in Walker’s Pond were an unusual dwarf or pygmy version of the fish. This study concluded that juvenile fish in Walker Pond left the pond after a year and a half, as opposed to the average of around six months. This started them off in life with a slower growth rate that resulted in smaller adults. Because of this, Walker Pond alewife are the only alewife, where runs currently exist, that cannot, by law, be taken (even non-commercially) by residents of Maine.

Bagaduce towns understand that their connection to these fish comes from historic use and observations, which is evident when talking to members of the alewife committees who often speak of alewife experiences when they were children, harvesting with their parents, and the streams being “black with fish.”

It is because of this historic importance of harvest and use that the towns strongly expressed their interest in preserving Walker Pond fish. But they also wanted to be able to catch and connect with them again. In an attempt to better understand these “pygmy” alewives, MCCF staff are working on a comprehensive plan to determine what makes them different and give the towns the best chance at future harvests if they can be sustainable.

Plankton samples at Walker’s Pond are collected from April to November to determine if unique natural food sources for juvenile alewives cause this unique life history. Adult and juvenile alewife samples are collected and are DNA-tested and accurately aged to determine if this population is genetically distinct and to show exactly how long juvenile fish spend in the freshwater environment before heading to sea. The same data was collected from Pierce’s and Wight’s ponds for comparison.

Alongside this work, the Downeast Salmon Federation (DSF), a leader in community-based anadromous fish restoration based in Columbia Falls, has been surveying juvenile alewife populations in Downeast Maine, including the Bagaduce Estuary and its tributaries, by using a beach seine. These surveys are done every two weeks, from August through October, in a corner of the Bagaduce known as Northern Bay. The number of fish and the variety of species indicate that Northern Bay is a highly productive juvenile fish nursery. Other survey sites include the Union River in Ellsworth, Pleasant River in Columbia Falls, Machias River and East Machias River.

MCCF has been instrumental in bringing the Bagaduce towns of Brooksville, Penobscot and Sedgwick together to discuss the future of their local alewives. Representatives from each town have come together to form a three-town working group that is laying the groundwork for a more formal group in the future. Like these towns working together, MCHT, MCCF, and DSF also work together in the Downeast Fisheries Partnership. They understand that in order for Maine coastal communities to thrive into the future there will need to be a united front of groups and individuals who understand the issues.

Alewife is a species far below its historic population levels, due in large part to the loss of habitat connectivity as a result of dams, impassable road culverts, and other obstacles. Populations are rebounding in Maine thanks to the work of these individuals, communities, and partners.