Larval stages of the American lobster (Homarus americanus). Photos by Jesica Waller
Newly hatched lobster larvae molt sequentially through these four stages before settling onto the sea floor.
Background:
The Maine Department of Marine Resources (DMR) conducts long-term monitoring for larval lobsters at four fixed sites in the Midcoast region. Originally piloted in 2017 in collaboration with Dr. Eric Annis (Hood College), our monitoring dataset officially begins in 2018. Our current survey is a point of comparison to historical work conducted regionally, and provides the youngest life stage dataset within our suite of lobster monitoring programs at ME DMR.
Survey Objectives:
- Evaluate the density of larval lobsters in the Midcoast region (Zone E).
- Track the seasonal patterns of larval density within each year.
- Document the plankton diversity during the larval season to track potential prey availability.
- Monitor seasonality in the larval habitat by collecting complete CTD profiles across sites (temperature, salinity, dissolved oxygen, pH).
Map of Survey Sites
We sample four fixed sites (2, 3, 8, 9) for larval lobster density weekly or bi-weekly throughout the larval season. Our boat tows a neuston net alongside the boat for fifteen minutes, three times per site. We calculate average densities of each stage of larval lobster for each site on our sampling day. At site 9, we also collect zooplankton samples and a full water column CTD cast consisting of temperature and salinity. Starting in 2024, we began taking full CTD casts (temperature, salinity, dissolved oxygen, and pH) at all the fixed larval lobster survey sites, as well as four intermediate sites, to extend the work started by the Maine Coastal Mapping Initiative (MCMI) program in 2023. Below is the map of our current survey sites as of 2024.
ME DMR Larval Survey Data
To use the larval survey dataset or to obtain more detailed information, please contact Heather Glon and cite the following paper: Glon, Heather E., Jesica D. Waller, Eric R. Annis, Joshua T. Carloni, Maura Niemisto, Carl Wilson, Kathleen Reardon, and Robert Russell. "Larvae of the American Lobster Homarus americanus H. Milne Edwards, 1837 (Decapoda: Astacidea: Nephropidae) in Midcoast Maine USA from 2018-2023: Density, Seasonality, and Carapace Lengths." Journal of Crustacean Biology, vol. XX, 2025,https://doi.org/10.1093/jcbiol/ruaf017.
Maine DMR Larval Lobster Survey data dashboard (2018-Present)
Maine DMR Larval Lobster Survey CTD environmental monitoring dashboard (2024-Present)
2021 Expanded Gulf of Maine/Georges Bank Larval Survey Project
Because of the lack of information on large-scale larval distribution, in 2021 an industry-led collaboration with government and academic scientists, including DMR staff, conducted a season-long survey at sites spanning approximately 186 miles of coastline. The survey established seasonal abundance patterns of larvae and their prey in the Gulf of Maine. A report on the study can be found here.
Contacts
Heather Glon, Lobster Research Biologist & Larval Survey Coordinator