UC Santa Barbara

Anthropogenic greenhouse gas emissions have resulted in profound changes in the physical and chemical properties of the ocean that have serious implications for all levels of ecological organization. Concomitant risk to fisheries, economies, and coastal livelihoods that depend on marine species, coupled with projections of intensifying environmental changes, challenge society’s capacity to adapt and manage effectively. The variety of complex impact mechanisms and uncertainties associated with interactions between biological and socio-economic components of fisheries necessitate integrated assessments of vulnerability and adaptive capacity at scales necessary for local-scale adaptation planning. This dissertation integrates fishery-dependent commercial landings data, regional oceanographic anomaly data, semi-structured interviews with fishermen, and fishermen feedback sessions to understand the how the commercial sectors of two of California’s most economically valuable fisheries (California spiny lobster and California market squid) will respond to future change, informed by their past responses to short-term historical climate variability, fishermen’s perceptions of constraints to adaptive capacity, and their perceptions of the efficacy of fisheries management. Given that risk and/or adaptive capacity have not been evaluated for either fishery, and considering the notable differences in these fisheries, they were ideal study species for a comparative research assessment. Chapter 1 shows that market squid fishermen have been able to adapt to dramatic shifts in the geographic range of the fishery given their high mobility. However, fishermen’s responses to change are highly contingent on how a given change manifests in the fishery, as well as characteristics of individual fishermen. Chapter 2 revealed important similarities and differences with regard to the likelihood that spiny lobster and market squid fishermen would perceive a given factor as a constraint, as well as the extent to which different domains of adaptive capacity influence their perceptions of constraints. Constraints relating to fishery governance were the most commonly perceived constraints in both fisheries; however, there were clear differences in perceptions of individual-level constraints (i.e., mobility and knowledge). Chapter 3 shows that market squid and spiny lobster fishermen are generally supportive of fishery management, as well as specific management or conservation tools, with lack of support often indicative of a desire for stronger, scientifically-backed management measures and inclusive decision-making processes. This dissertation highlights the multiple dimensions of adaptive capacity in two highly valuable fisheries, and the critical importance of designing management and decision-making processes that contribute to resilience. Key differences between these fisheries brings explicit attention to the multitude of factors that influence fishermen’s responses and perceptions, and the critical need for multi-species approaches to studying fisheries. This research also highlights the need for contextual, place-based management policies and adaptation strategies that integrate the knowledge, lived experiences, and perceptions of resource users to proactively address climate change impacts on fishermen’s livelihoods.