Date of Award

Spring 5-5-2023

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Master of Science (MS)

Department

Marine Biology

Advisor

Richard Wahle

Second Committee Member

David Fields

Third Committee Member

Rachel Lasley-Rasher

Abstract

The American lobster (Homarus americanus) plays an integral role in the coastal Northwest Atlantic as a benthic consumer and the target of the most valuable single-species fishery in North America. In the past decade, benthic recruitment of juvenile lobster has declined, even as egg production has increased, suggesting heightening levels of larval mortality. Recent correlative studies in the Gulf of Maine further suggest early stage larval survival may be related to the supply and composition of planktonic foods. Despite these correlative studies and the economic importance of the species, relatively little is yet known about how larval lobster interacts with its prey in the pelagic environment. As development progresses through the four planktonic larval and postlarval stages, the young lobsters rely heavily upon zooplankton for food. During these early developmental stages, lobster larvae undergo significant morphological changes. This study used a combination of laboratory-based feeding experiments and video recordings to examine changes in feeding behavior and ingestion rates between larval stages. We observed dramatic stage-to-stage improvements in the capacity to pursue, capture, handle, and ingest specific prey, especially after the metamorphosis to the postlarval stage. The results highlight the vulnerability of the early life stages to low food densities. They also elucidated differences in the ability of specific prey taxa to evade predation. Quantifying the interactions between larval lobsters and their prey enhance our understanding of how larvae interact with the pelagic food web, the fraction of available zooplankton representing viable food sources, and how lobster larvae may be impacted by altered prey availability associated with climate change. A supplementary document submitted separately contains an exercise in scientific storytelling, with the contents of the entire thesis summarized in the form of a children’s story.

Additional Files
The Very Hungry Lobster Larva (Childrens Book).pdf (3036 kB)
A summary of the thesis in the form of a children's book.
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