Maine American Lobster Fishery (United States)
The American lobster (Homarus americanus) fishery in the state of Maine (US) was examined to identify ecological, socio-economic, and governance attributes that influence its resilience to ocean warming and marine heatwaves. The combination of warming trends and heatwave events have both benefitted and challenged the fishery, and the fishery has adapted to challenges in ways that have enhanced resilience, particularly to recent heatwaves. Conservation measures have enhanced population abundance under recent warming conditions, creating an ecological buffer that supports fishery resilience. The polycentric, participatory nature of the governance system aligns industry and agency approaches to managing the fishery, enabling adjustments to changing fishery conditions. Further, certain socio-economic attributes, such as wealth and reserves and place attachment, have supported fishery resilience, but others such as limited mobility, economic opportunity, and economic diversity may constrain resilience to future climate-related fishery changes.
American lobster (Homarus americanus) has supported the highest-value single-species fishery in the United States since 2014. Nearly 80% of U.S. landings occur in the state of Maine, where lobster alone represents over 75% of the value of all marine fishery landings (NMFS 2022). More than 6000 owner-operators are licensed to participate in the fishery (Maine Department of Marine Resources 2022), which is largely prosecuted by small vessels that operate in coastal waters, but the number of larger vessels operating in offshore waters has increased in recent years. The fishery is of high economic, social, and cultural value in the state, particularly in coastal communities in midcoast and downeast Maine, where reliance on this fishery has grown in conjunction with increases in lobster abundance and declines of other species (Steneck et al. 2011).
The American lobster fishery is cooperatively managed by the Northeast U.S. states and the federal fishery management authority, NOAA Fisheries, through the Atlantic States Marine Fisheries Commission. Individual states manage the fishery out to three nautical miles from shore, and NOAA Fisheries manages it 3-200 nautical miles from shore. In Maine, the fishery is co-managed with lobster harvesters through a zone-based arrangement; state waters are divided into seven lobster management zones, each of which is managed by an elected council of lobster license holders that fish in that zone. The zone councils propose rules—including limited entry and trap limits—for managing the fishery in their zone that may then be adopted as regulations by the Maine Commissioner of Marine Resources (Acheson et al. 2000). This arrangement aligns with the place-specific nature of the fishery, while also creating a multi-level governance structure that spans local, state, and federal authorities.
Climate Impacts and Responses
The Maine lobster fishery operates in a rapidly changing ecosystem. Sea surface temperature in the Gulf of Maine has been warming three times faster than the global average for the past 40 years, and marine heatwaves have become a frequent occurrence in the past decade (GMRI 2022). This warming—in conjunction with benefits from long-standing industry conservation measures—supported growth of the lobster population and fishery in Maine over the past two decades (Le Bris et al. 2018). The resilience of the fishery system was tested by a marine heatwave in 2012, during which the early onset and high volume of landings created substantial supply chain disruptions that led to a price collapse (Mills et al. 2013, Pershing et al. 2018). Industry responses following the 2012 heatwave included (1) adapting handling practices on vessels to reduce temperature-related physiological stress experienced by lobsters, (2) establishing flexible transportation contracts to move lobster from the dock to processing facilities, (3) increasing processing capacity, and (4) pursuing marketing measures to expand outlets for the product (Pershing et al. 2018). In addition, scientific forecasting capacity was developed to predict the start of the high-landings period based on seasonal water temperatures (Mills et al. 2017). These responses have buffered impacts to the fishery during subsequent marine heatwaves (Pershing et al. 2018). However, multi-decadal population projections indicate a downturn in the lobster population with ongoing warming (Le Bris et al. 2018), as well as shifts in the spatial distribution of lobster, with the most substantial declines projected for coastal waters of southern Maine and moderate declines in the midcoast to downeast regions (Allyn et al. 2020, Tanaka et al. 2020).
Resilience Attributes and Linkages
Resilience of the Maine lobster fishery to ocean warming and marine heatwaves has been influenced by attributes of ecological, socio-economic, and governance dimensions of the fishery (Mason et al. 2022). Long-standing conservation measures initiated by the industry and incorporated into management measures have helped build a healthy lobster population in the Gulf of Maine (Acheson and Gardner 2011). Since 1917, reproductive female lobsters have been protected by ‘v-notching’, which entails harvesters cutting a v-shaped mark into the tails of egg-bearing female lobsters. Landing v-notched lobsters is prohibited, and the notch provides an indication to subsequent harvesters that those lobsters should be returned to the ocean. In addition, since the 1930s, the Maine lobster fishery has imposed harvestable size limits to ensure lobsters reach maturity and to protect the most reproductively-valuable large lobsters. These approaches were spurred by a resilience mindset in the industry, which led to management measures being formalized through a polycentric, participatory governance system that is responsive to industry needs and ideas. These measures have subsequently helped attain high population abundance in the Gulf of Maine lobster stock and provided a boost to the stock as water temperatures in the region warmed during the 2000s (Le Bris et al. 2018), yet v-notching compliance appears to be waning as the population has grown (Mazur and Johnson 2020). The abundant population—coupled with generally strong market conditions—have conferred economic benefits and supported growth of wealth and reserves in this fishery.
Additional socio-economic attributes have enabled industry actions that supported resilience during warming and marine heatwaves. During the 2012 marine heatwave, harvesters were able to catch and land large volumes of lobster, but the supply chain was not prepared to handle the amount of product so early in the season. Since then, efforts to move towards more flexible and agile infrastructure and cross-scale integration of actions by harvesters, dealers, processors and marketers have reduced the cascade of impacts during subsequent heatwaves (Pershing et al. 2018). In addition, this fishery generally benefits from high knowledge diversity, knowledge access, and learning capacity that arise from industry observations and long-term perspectives on ecosystem and fishery changes; scientist-industry partnerships; and a suite of monitoring and research efforts through governmental, academic, and non-profit institutions.
The success of this fishery—including the healthy stock and lucrative economic returns—have conferred benefits to its participants, but it has also led to even greater concentration of participation and high levels of social and economic reliance on the fishery in Maine’s coastal communities. While this high reliance and strong sense of place attachment has driven a conservation ethos in this fishery, they may constrain resilience in the face of continued climate change. If the population declines or its distribution shifts, place attachment to specific lobster zones, as well as limited mobility of small vessels, will restrict options for the fishery to move with the stock as it shifts. Moreover, many of Maine’s fishing communities currently have limited economic opportunities and economic diversity outside of the lobster fishery, as well as strong cultural identities associated with the fishery—situations that make it challenging to diversify livelihoods within and beyond fishing, as has often been relied upon for resilience in many resource-based economies. Finally, climate-related changes in other fisheries, protected species, and ocean uses may create new challenges for the Maine lobster fishery, and governance frameworks are currently limited in their ability to support cross-scale integration of decision-making across sectors.
Ecological, socio-economic, and governance attributes of the Maine lobster fishery have all contributed to resilience of this fishery in the face of ocean warming and marine heatwaves, with stock health, industry actions, and governance arrangements being important to the success of the fishery through recent climate-related changes. A resilience mindset in the industry, coupled with participatory governance arrangements, supported growth of the lobster population. The healthy stock provided a basis for growth of the fishery, which has generated economic and social benefits across many coastal communities in Maine. Recent climate-related changes have been buffered by responsive industry actions across multiple levels of the supply chain. While these attributes have supported climate resilience in the fishery to date, projected changes in stock abundance and distribution as well as potential climate-related changes external to this fishery will require ongoing adaptation to buffer impacts and sustain benefits for fishery participants and their communities. Strong place attachment, limited mobility, few economic opportunities, and the lack of integrated governance that spans ocean sectors may constrain adaptation and resilience of this fishery into the future.
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Steneck, R.S., T. P. Hughes, J. E. Cinner, W. N. Adger, S. N. Arnold, F. Berkes, S. A. Boudreau, K. Brown, C. Folke, L. Gunderson, P. Olsson, M. Scheffer, E. Stephenson, B. Walker, J. Wilson, and B. Worm. 2011. Creation of a guilded trap by the high value of the Maine lobster fishery. Conservation Biology 25(5): 904-912.
Tanaka, K.R., M. P. Torre, V. S. Saba, C. A. Stock, and Y. Chen. 2020. An ensemble high-resolution projection of changes in the future habitat of American lobster and sea scallop in the Northeast US continental Shelf. Diversity and Distributions 26(8): 987-1001.
Acknowledgments: Collaborations and conversations with Andrew Pershing, Arnault Le Bris, Richard Wahle, Katherine Maltby, Kanae Tokunaga, Carl Wilson, Curt Brown, and many others involved in the NSF Coastal SEES project, Resilience and adaptation of a coastal ecological-economic system in response to increasing temperature, and the Maine Department of Marine Resources Lobster Research Collaborative have shaped my understanding and interpretation of climate resilience in this fishery. Funding from the Sea Grant American Lobster Initiative through NOAA award NA19OAR4170398 supported development of this case study.
Photo: Lobster fishing boats and shoreside infrastructure in Stonington, Maine. © Katherine E. Mills