Date of Award

2024

Document Type

Honors Thesis (Open Access)

Department

Colby College. Environmental Studies Program

Advisor(s)

Justin Becknell

Second Advisor

Cait Cleaver

Third Advisor

Amanda Gallinat

Abstract

Northern Shrimp (Pandalus borealis) populations within the Gulf of Maine collapsed in 2011 following the first year that sea surface temperature surpassed 10ºC. The population collapse resulting in a moratorium in 2014. The waters of the Gulf of Maine have been rising at a rate of 0.045ºC per year, changing predator distribution, prey distribution, as well as Northern Shrimp biological variables. There has been very little recovery to the Northern Shrimp stock despite the fishing moratorium and the answers behind the collapse and lack of recovery remains enigmatic. Therefore, this two-chapter study includes a literature review and a research paper trying to determine the factors and mechanisms behind the Northern Shrimp population crash. The first chapter is a literature review investigating the direct and indirect impacts of increasing water temperatures on the Northern Shrimp stocks in the Gulf of Maine and Eastern Canada. The second chapter is a research paper addressing the question: Are there any patterns between SST and Northern Shrimp biological variables in either the GOM or the Scotian Shelf? The results demonstrate a possible temperature threshold of 10.1ºC for sea surface temperature and 8.1ºC for bottom temperature that above results in both biomass and spawning stock biomass collapse. Temperatures above these thresholds demonstrate high mortality rates in Northern Shrimp larvae and adults. The implications of these findings include Northern Shrimp fishery never returning to the Gulf of Maine and the Scotian Shelf in Eastern Canada possibly being the next location to experience the population collapse.

Keywords

Sea Surface Temperature, Bottom Temperature, Moratorium, Total Biomass, Spawning Stock Biomass

Alicia Hober

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