The Relationship between Seasonal Migrations of Berried Female Lobster Homarus americanus, Egg Development and Larval Survival

Primary tabs

Project Type: 
Research
Project Number: 
R/MED-9
Inception Date: 
2006
Completion Date: 
2008
Theme Area: 
Fisheries Resources

Participants:

Winsor Watson UNH - Department of Biological Sciences Principal Investigator
Edward Heaphy Boat Captain Collaborator
David Shay Boat Captain Collaborator
Michael Flanigan Boat Captain Collaborator
Edward Foye Boat Captain Collaborator
Mark Regoulinsky Boat Captain Collaborator
Gary Glidden Boat Captain Collaborator

Students Involved:

Jason Goldstein UNH - Department of Biological Sciences
Tom Langley UNH - Department of Biological Sciences
Arthur Lambert University of New Hampshire
Josh Brown University of New Hampshire
Joy Stronk University of New Hampshire
May Grose University of New Hampshire
Lisa Harvey University of New Hampshire
Elizabeth Dubofsky UNH - Department of Biological Sciences
Abstract: 

The work outlined in this proposal is designed to provide detailed information about the fine-scale seasonal movements of berried female American lobsters (Homarus americanus), the relationship between these movements and specific habitats, depths and water temperatures, and ultimately the influence of these movements on the number of viable larvae that hatch from their eggs. These data will provide the first detailed, year-round view of the reproductive life history strategy of berried female lobsters. As a result, this study will provide vital information about the sources of new recruits to the fishery and the interactions between lobster stocks.

Objectives: 

Our overall goal is to quantify seasonal changes in the daily activity patterns and habitat preferences of berried female lobsters and determine if these movements influence the quality and quantity of the new recruits they produce. This goal will be achieved by completing the following specific objectives:

1) Quantify the daily movements and long-term migration patterns of 10 berried lobsters and 10 control (not berried) female lobsters for an entire year, during each year of the two-year study.

2) Determine if there are predictable seasonal shifts in the behavior and habitat preferences of small vs. large berried females, and berried females in comparison to control lobsters.

3) Raise eggs and larvae under different thermal regimes in the laboratory to test the hypothesis that female movements that lead to smaller fluctuations in temperature result in better larval survivorship and thus improved reproductive success.

Methodology: 

This investigation will involve both laboratory and field studies. In the field, control and berried lobsters will be tracked continuously for a period of at least 10 months using a combination of three different types of ultrasonic telemetry systems: a fixed array (VEMCO VRAP) system to determine fine-scale details, manual tracking to determine large-scale movements, and listening stations to facilitate tracking of large-scale movements during certain times of the year. In the laboratory, berried lobsters will be held under thermal regimes designed to mimic the temperatures they would experience during the time when they were incubating their eggs in nearshore and offshore location. The influence of these two thermal regimes, as well as constant  temperatures, on egg development and larval survival will be assessed to determine if the seasonal movements of berried lobsters serve to optimize reproduction.

Rationale: 

This study will provide answers to several long-standing questions about the life history strategies of berried female lobsters. It will be the first to determine if the movements of females have an impact on their reproductive output and thus the preservation of the species. Our data will also help identify:

1) Habitats where berried females aggregate so that lobstermen can avoid these locations

2) Areas where berried females release their larvae, making it possible to model the fate of larvae, identify the source of recruits and determine which populations or stocks overlap.

 These types of data are essential in order to sustain this valuable marine resource through establishment of sound fishing practices and development of proper management strategies.
Accomplishments: 
2012

Model Developed to Predict Hatching of Lobster Eggs

Researchers developed a model that can be used to predict when lobster eggs will hatch based on the local seasonal fluctuations in water temperature. This ability to forecast egg hatch is vital for resource managers to more accurately assess lobster populations and successfully manage the fishery.

Accomplishments

 
1.     We developed several approaches and method that will help us and other scientists complete similar studies in the figure. For example, we figured out how to tell if early eggs were fertile using a novel staining method and we also developed a technique for determining when eggs were fertilized.
 
2.     Our drifter work along the coast prompted us to conduct similar studies in the estuary and these gave rise to a new project we will be starting this summer.
 
3.     We were able to establish some good working relationships with the NHFG as well as the private sector (Normandeau) and commercial lobstermen.
 

Economic and societal benefits

 
The lobster fishery is one of the most lucrative and important fisheries in New England. Our work is designed, in part, to help us understand the life history and seasonal movement patterns that are typical for American lobsters, particularly reproductive females. Several of our findings, when published and accepted by the scientific community, will impact how we manage lobsters in the most sustainable way possible. For example, this work will help us understand why lobsters migrate offshore, when larvae will hatch and where the larvae will eventually settle. This will have a huge impact on managers’ views of what constitutes a lobster stock. If NH lobsters provide recruits for Massachusetts waters, then the entire stock should be managed as one unit.
 
Number of coastal and marine issue-based forecast capabilities developed and used for management
 
This project has yielded very valuable information about the impact of water temperature on the movements of lobsters and the development of their eggs. It has also led to a model that can be used to predict when lobster eggs will hatch, based on the local seasonal fluctuations in water temperature. Finally, it has yielded the beginning of a broader picture of how female movements influence the distribution of new recruits to the fishery. All this information is vital for creating models that are used to manage the lobster fishery.
 
Information used by managers to improve ecosystem-based management
 
One of the most surprising findings from this study was that the bottom habitat may have a very important impact on the tendency of lobsters to undertake seasonal migrations. The discovery that certain sections of the Great Bay estuary are very attractive to lobsters alters our previous view of the estuary as a lobster habitat. Furthermore, the finding that lobster larvae are likely retained in the estuary suggests that it might sustain a self-sufficient population of lobsters and this has a big impact on ecosystem based management practices.
 
Improving the probability of securing additional external funding
 
This study laid the groundwork for three successful grant proposals. One was a Sea Grant concerned with sperm limitation. One was a project funded by the Southern New England Collaborative Research Institute, concerned with lobster migrations, sperm limitation and life history strategies. The third was a small grant from the UNH Marine Program to carry out the drifter work that was not previously included as an objective. It should also be pointed out that, based in part on our success, several state agencies have initiated comparable research programs. The fourth grant we received, based on preliminary data from this project, was a NEC grant to localize berried females off the coast of N.H. and determine if their larvae took the trajectories predicted by our drifter studies. Finally, we were just funded by Sea Grant to study lobster recruitment inthe Great Bay estuary.
 
Education and outreach
 
At least 2 graduate students, 7 undergraduates and a number of commercial lobstermen have been involved in this project. One graduate student, Jason Goldstein, will use the bulk of data collected to complete his Ph.D. thesis. His work on this project also helped him secure a NEERS Fellowship to conduct similar studies in the Great Bay estuary.

 

Many of the undergraduates have gone on to successful jobs, or professional schools, following their experiences working on this project. We continue to interact with many of the commercial lobstermen and provide them with updates about the project.

 
We have also provided information about lobster movements and the influence of water temperature on lobster movements to the agencies involved in making decisions about lobster management.
 

Publications

Available from the National Sea Grant Library (use NHU number to search) or NH Sea Grant

Journal Article

  • Johnson, K., J. Goldstein and W. Watson. Two methods for determining the fertility status of early-stage American lobster, Homarus americanus, eggs. Journal of Crustacean Biology 31(4):693-700, October 2011.
  • Goldstein, J., T. Pugh, E. Dubofsky, K. Lavalli, M. Clancy and W. Watson (2014). A noninvasive method for in situ determination of mating success in female American lobsters ("Homarus americanus"). Journal of Visualized Experiments 84:e50498, February 2014.
  • Goldstein, J. and W. Watson (2015). Seasonal movements of American lobsters in southern Gulf of Maine coastal waters: patterns, environmental triggers, and implications for larval release. Marine Ecology Progress Series 524:197-211, 2015.
  • Goldstein, J. and W. Watson (2015). Influence of natural inshore and offshore thermal regimes on egg development and time of hatch in American lobsters, Homarus americanus. Biological Bulletin 228(1):1-12, February 2015.

Thesis/Dissertation

  • Goldstein, J. (2012). The impact of seasonal movements by ovigerous American lobsters ("Homarus americanus") on egg development and larval release. Doctoral Dissertation, University of New Hampshire.