Aquatic Ecology Update for Sea Lamprey Nest Surveys

Sea Lamprey nest survey conducted with community science volunteers on the Ashuelot River in 2025, led by Dr. Kate Buckman.

The Connecticut River Conservancy (CRC) is thrilled to have recently welcomed Dr. Stefanie Farrington as the Aquatic Ecology Program Associate, to support our Aquatic Ecologist and Program Manager, Dr. Kate Buckman in implementing and growing CRC’s ecology programming. Among the priorities is data analysis for the past 5 years (2020-2025) of sea lamprey nest surveys conducted with community science volunteers on different tributaries in the Connecticut River watershed. Stefanie jumped right into the work, putting her coding skills to use in creating mapping tools allowing us to visualize the data collected through last year.

We have started looking for high-level patterns in the data (number of nests, types of nests, distance covered) and how these may have varied between years and between sites. The charts below represent some findings so far, but we’re not jumping to any conclusions just yet. We are planning to continue the nest surveys this year, and then release a more comprehensive analysis of findings and trends for 2020-2026 after this summer’s activities. 

This sites map shows all the locations where CRC has led or participated in a sea lamprey nest survey at least once from 2020-2025 (no surveys were conducted in 2023 due to flooding). 

This map shows where the Ashuelot River (NH) has been surveyed annually from 2020-2025, with nest occurrences being clustered in the same approximate areas in the river each year. The number of nest occurrences, relative numbers of nest types (single, cluster, and community), and survey distances varied by year for the Ashuelot River.

This map shows where the Green River (MA) was surveyed in 2025, with nests distributed in patches of suitable habitat. 

This combined histogram map shows annual nest data for both sites above, with the majority of counted occurrences being single nests. 

We will be conducting more formal analyses following this year's sampling to examine trends in occurrence, density, and habitat associations across the Connecticut River watershed.

Stay tuned for when community science events open up in June so you can join us in documenting more sea lamprey nests this year!

P.S. In the meantime, you can hear Kate's recent interview about sea lamprey in our rivers on WHMP's Talk the Talk radio show (scroll down to see where you can jump right to Kate's portion of the show).