Date of Award

Fall 12-16-2022

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Master of Science (MS)

Department

Marine Biology

Advisor

Damian Brady

Second Committee Member

Deborah Bouchard

Third Committee Member

Richard Wahle

Abstract

In live seafood industries, maintaining product quality and survivorship are critical aspects of the supply chain infrastructure. Post-harvest mortality in the American lobster (Homarus americanus) fishery can result in a significant loss in revenue for the largest single species fishery in North America. In Maine, the wholesale lobster distribution supply chain directly and indirectly supports state and local economies, providing almost $1 billion in revenue and dominates the fishery, producing 82% of the total lobster landings in the USA (Donihue, 2018; NOAA, 2021). However, at least 2% of the lobster landed in Maine die before they reach consumers, representing an industry loss of roughly 952 metric tons, or $14.5 million in value every year (ME DMR, 2022). The lobster supply chain is a network of harvesters, dealers, and distributors that facilitates the transport of live product domestically and internationally. The majority of product loss comes in the form of delayed mortality as a result of stressors within the supply chain. Because of the high volume of lobster transported through the supply chain and its many links, a standard protocol is needed to quickly diagnose whether a high-value live lobster will survive the trip to the consumer. A reflex action mortality predictor (RAMP) model was developed to reliably predict subsequent mortality days after exposure to the supply chain. RAMP models have been successfully used in commercially important fish and crustacean industries to predict discard mortality, but has never been applied in a post-harvest context or for a Homarus species. To model and predict delayed post-harvest mortality using the RAMP model, a three-part methodology was completed and followed by a pilot field test to demonstrate the feasibility of this method. An initial investigation was conducted to identify which reflexes were stereotypic of a healthy lobster. Subsequently, a holding experiment that monitored the survival after exposure to the supply chain was conducted at lobster dealer holding facilities. Carapace length, sex, shell hardness, injuries, and discrete reflex actions of the experimental lobsters were recorded to build logistic RAMP models. Results suggest that carapace length along with four specific reflex actions and five types of injury are significant predictors of mortality up to five days after arrival to a lobster dealer facility. The reflex actions are: eye motion, pereiopod motion, 3rd maxilliped retraction, and 2nd maxilliped motion. The five injuries are: missing chelae, damaged chela, damaged antenna, damaged carapace, and damaged uropod. Measuring these significant predictors takes no more than 20 seconds per lobster. A final, proof-of-concept investigation was conducted at three transfer points in the supply chain to test the practicality of the RAMP method and to test the differences of predicted post-harvest mortality among these sites. This model can be an important tool in identifying supply chain stressors that impact lobster quality and inform efforts to improve the efficiency and resiliency of the industry. Developing a RAMP model to predict post-harvest mortality demonstrates the feasibility of using reflex actions as predictors of mortality in a novel context, acting as a foundational method for future studies. The highly predictive, non-invasive, quick, and cost-effective nature of this method has potential to become a versatile tool for both industry and scientific applications.

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