Pawtuckaway Lake Association

The NH Center for Freshwater Biology Research has published a new research paper providing an assessment of plankton populations, toxic cyanobacteria, and the potential impact of introduced marine alewife on Pawtuckaway Lake. Since the State of NH Department of Fish and Game has been stocking Pawtuckaway Lake with marine alewife, many residents have wondered what the impact would be on the lake ecology. This new research paper by  Jessica V. Trout-Haney, Department of Zoology, University of New Hampshire, Durham provides scientific evidence of a link between the alewife and toxic cyanobacteria blooms on the lake.

In summary, cyanobacteria and other phytoplankton populations are responsible for the introduction of dangerous toxins into the lake. These phytoplankton are normally kept in check by the lake's zooplankton population which feed on them. The study demonstrates that marine alewife ( a non-native species) feed on the lake's zooplankton population thereby reducing the natural predators to the dangerous phytoplankton populations in the lake.

This research paper provides scientific data which backs up many lake residents (admittedly, non-scientific) feelings that algea blooms have increased on the lake since the State began stocking the lake with marine alewife. The State stocks Pawtuckaway Lake with alewife to provide feeder fish for ocean sport fishing populations. In the fall when the lake is drawn down, many of the alewife are washed downstream into Great Bay where they mature and provide sustinance for game fish.

Financial support for the study was provided by the Town of Nottingham and the Pawtuckaway Lake Improvement Association. Additional equipment and supplies support was provided by the UNH Center for freshwater Biology and the NH Lake Lay Monitoring Program. PLIA Member Therese Thompson provided invaluable assistance throughout the project.

If you would like to learn more about the study, you can download it here: Research Paper