University Events

Description: The School for Marine Science and Technology
Department of Fisheries Oceanography
Seminar Announcement

"Challenges facing a lobster stock on the 'losing' end of climate change"

Tracy L. Pugh, PhD
Senior Marine Fisheries Biologist, Invertebrate Fisheries Project
MA Division of Marine Fisheries

Wednesday, April 6, 2022
2:30 pm to 3:30 pm
SMAST East, Rooms 101/102
Also Via Zoom

Abstract:
The Homarus americanus lobster population in the United States is currently assessed as two separate stocks: the Gulf of Maine stock, which has recently
experienced rapid growth and expansion, and the Southern New England stock, which is depleted and experiencing recruitment failure. The disparate
trajectories these two stocks have experienced over the past two decades appear to be related to the changing climate, and illustrate how a single species
could be both a ‘winner’ and a ‘loser’ with respect to climate change impacts. Populations living at the warmer extent of the species’ geographic range are
more likely to be tipped over the threshold into negative impacts, due to the degree to which environmental changes affect population vital rates. Here we
will focus on the Southern New England (SNE) lobster stock and review various data sources from the published literature and the Atlantic States Marine
Fisheries Commission’s U.S. lobster stock assessment, as well as preliminary and unpublished datasets, to explore how changes in the environment appear to
link to multiple different stressors on this resource. Recent estimates of spawning stock biomass are similar to SSB estimates from the 1980s, but have resulted in fewer recruits compared to historic recruitment levels. This regime shift in stock productivity coincides with warming inshore waters observed in time series of sea surface and bottom water temperatures since the late 1990s, and increasingly long durations of extreme summer warmth. This excessive warmth negatively impacts the quality of inshore settlement habitat and may have caused an offshore shift in the distribution of adult lobsters, which subsequently influences larval dispersal patterns. Warmer waters also appear to be related to various emerging diseases observed in inshore SNE lobsters, including the most commonly recognized epizootic shell disease. The warmer SNE environment has allowed for the northwards expansion and population explosion of black sea bass, a known lobster predator. Finally, on top of these various stressors, commercial fishing has continued; although landings, effort, and overall participation in the fishery have declined dramatically over time. From the southern extent of the species range, warming waters have presented a number of challenges to the SNE lobster stock, and the question remains as to whether this stock can stabilize at lower levels of abundance, or will continue to decline.
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Zoom Link
https://umassd.zoom.us/j/93758230260?pwd=OHJ5UDloQkZZaCtXcTlBNlR6Qm0rQT09
Meeting ID: 937 5823 0260
Passcode: 426839

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For additional information, please contact Sue Silva at s1silva@umassd.edu