Social-ecological Heterogeneity Shapes Resilience of Small-scale Fisheries: An Interdisciplinary Analysis of the Mexican Chocolate Clam Fishery in Loreto, Mexico

All benefits provided by natural systems are embedded within coupled social-ecological systems (SESs). Fisheries are clear examples of SESs: through fishing, humans affect ecosystem structure and functioning, and in turn, receive benefits, including sustenance, employment, and cultural value. Resilience, the ability to maintain structure and function in the face of change, is key to sustaining the social and ecological components of fisheries-related SESs and their interactions. Many factors contribute to resilience, including heterogeneity. By identifying heterogeneity in these complex systems, we are better able to understand the capacity of fishery-related SESs to adapt to change, and contribute to management that protects valuable services. In this dissertation, I ask: 1) How are SESs associated with marine fisheries shaped by environmental, social, and institutional heterogeneity, and 2) what are the implications of this variation for resilience and adaptive capacity of fishers and the SES, in the face of changing environmental and socioeconomic conditions? To answer these questions, I employ an interdisciplinary approach focused on the chocolate clam (Megapitaria squalida) fishery in Loreto, Baja California Sur, Mexico. I conducted biological field studies, household surveys, interviews, ethnographic conversations, and developed fisheries models from my empirical work. Together, my results illustrate that management aligned with the biology of target populations and stakeholders’ goals is critical to sustainable fisheries. Heterogeneity among fishers affects their individual capacities to adapt to change. Maintaining a diversity of adaptive strategies is essential for individual adaptive capacity. Likewise, maintaining fishery heterogeneity, by ensuring all fishers are equipped to adapt, will strengthen community adaptive capacity. The chocolate clam provides diverse cultural and provisioning values to communities, and management that considers all benefits will be better equipped to account for the needs and knowledge of diverse stakeholders. Both formal and informal institutions shape fishing practices, and integrating them, via collaborative governance, would increase community participation in management and enhance fishery resilience. My interdisciplinary approach acknowledges the intricate web of human-resource interactions shaping fisheries and reveals how heterogeneity shapes SES resilience. Management that supports diversity in all forms will be better equipped to contribute to the resilience of these highly valuable and dynamic systems

Community Science in Support of Ecosystem-Based Management: A Case Study from the Damariscotta River Estuary, Maine, USA

Coastal marine ecosystems are dynamic social-ecological systems (SESs) that support diverse ecosystem services and human activities. The complexity of SESs means that ecosystem-based approaches are increasingly used to support coastal marine ecosystem stewardship. We report how a community science program in Maine, USA offers a model of organizational innovation to expand capacities for shellfish research and management. Since 2019, we have collaborated with local students, shellfish harvesters, and others in data collection, interpretation, and application, contributing to local shellfish management and ecosystem sustainability. We demonstrate how community-based social and ecological research can build adaptive capacities by centering local knowledge; generating long-term and fine-scale datasets; supporting community-led management and civic engagement; and contributing to field methods that people with varied lived experiences and training can implement in a sustainable fashion. Our approach can be adapted to other contexts, particularly in data-limited SESs that are experiencing observable social and ecological change

Heterogeneity among clam harvesters in northwest Mexico shapes individual adaptive capacity

Temporal variability driven by environmental shifts, biological processes, and socioeconomic fluctuations is inherent in natural resource-based sectors, including fisheries. In navigating these changes as opportunities for transformation, individual decisions play a key role. Understanding individual adaptive capacity, i.e., the ability to cope under changing or novel circumstances, and considering how this capacity is affected by diverse individuals' interactions with formal fisheries policy may allow a better understanding of adaptive capacity in a rapidly changing world. In Loreto Bay National Park, Baja California Sur, Mexico, the Mexican chocolate clam is an important source of food and livelihoods and is harvested by a diverse group of fishers. Understanding the diversity of fishers, their decision-making processes, and their adaptive strategies is essential for both anticipating fishery outcomes and predicting the capacity of different types of fishers to adapt to environmental and economic change. We used semistructured interviews with clam harvesters to ask: (1) What types of fishers exist within the chocolate clam fishery? (2) How do they differ in their adaptive strategies? and (3) What are the implications of diverse fisher types on individual adaptive capacity? We find that fishers of chocolate clams in this region operate within both the formal and informal sectors, have varied fishing strategies, and can be characterized into four discrete types. We also find that heterogeneity among fishers affects their individual capacities to adapt to changing conditions and disturbances, and fisheries policy constrains fishers' access to options by limiting secure access to fishing rights. Maintaining a diverse suite of adaptive strategies is essential for individuals to cope in the face of future disturbance and change. Likewise, maintaining heterogeneity in the fishery, by ensuring that multiple fisher types are equipped to adapt to future change, will strengthen adaptive capacity within the fishery and community

Seasonal variability shapes resilience of small-scale fisheries in Baja California Sur, Mexico

<div><p>Small-scale fisheries are an important source of food and livelihoods to coastal communities around the world. Understanding the seasonality of fisheries catch and composition is crucial to fisheries management, particularly in the context of changing environmental and socioeconomic conditions. While seasonal variability directly impacts the lives of fishers, most fisheries studies focus on longer-term change. Here we examine seasonal variability in the small-scale fisheries of Baja California Sur, Mexico based on 13 years of government fisheries data. We investigate how four fisheries indicators with direct relevance to ecological resilience–magnitude and variance of landed fish biomass, taxon richness and the proportion of top-trophic-level taxa in total catch–vary within and among years and at multiple spatial scales. We find that these resilience indicators vary both seasonally and spatially. These results highlight the value of finer-scale monitoring and management, particularly for data-poor fisheries.</p></div

Landed biomass by month for eight of ten fishing offices.

<p>Intra-annual variation in total fisheries biomass based on data reported to CONAPESCA by small-scale fishers from 2001–2013 for eight offices in Baja California Sur, Mexico. Error bars represent one standard error from the mean. Top biomass offices Santa Rosalía and San Carlos are excluded to better show trends in other offices.</p

Names of top taxa by biomass and value.

<p>Names of top taxa by biomass and value.</p

Ecological indicators vary by fishing office.

<p>Box and whisker plot showing significant spatial variation in all four ecological resilience indicators tested. Boxes represent 25^th to 75^th percentile for annual taxon proportion of top-trophic-level taxa, log variance in biomass, log total biomass, and taxon richness from 2001–2013, with points representing outliers. See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0182200#pone.0182200.g001" target="_blank">Fig 1</a> for locations of the fishing offices.</p

Map of Baja California Sur.

<p>Map showing the 10 fishing offices in this study. Reprinted from Pellowe unpub., under a CC BY license, with permission from Kara Pellowe, 2016.</p

Taxa composition of total biomass and value for each fishing office.

<p>Taxa composition of total biomass and value for each fishing office.</p