Date of Award


Document Type


Degree Name


Organizational Unit

Graduate School of Social Work

First Advisor

Leslie K. Hasche, Ph.D.

Second Advisor

Jennifer Bellamy

Third Advisor

Nicole Nicotera


Fish stock declines, Forced labor, Marine ecosystems, Slavery, Social-ecological justice


Despite media attention detailing labor abuses in fisheries, social-ecological systems research has largely failed to consider whether fish stock declines could be contributing to increases in forced labor slavery. Empirical fisheries data suggests, though not a ubiquitous response to declining stocks, many vessels will fish longer, farther from shore, and deeper in waters to maintain yields. This effort intensification increases production costs, and Brashares et al. (2014), consistent with slavery theory, posited cheap and/or unpaid labor as an approach to offset increasing costs and continue harvesting fish species at a rate otherwise cost-prohibitive.

Using fuzzy cognitive mapping - a participatory, semi-quantitative systems modeling technique that uses participants' knowledge to define complex system dynamics including fuzzy causality (causality represented as a matter of degree on a spectrum rather than certainty) - this study tested the hypothesis by interviewing stakeholders from global slavery hotspots. Data was obtained through semi-structured, qualitative interviews (n = 44) that included a cognitive mapping activity. An iterative, systematic, and inductive thematic content analysis condensed each map into major variables. Using structural models derived from graph theory, each cognitive map was converted into an adjacency matrix. From the matrix, influence metrics were calculated to elicit further information about each graph's structure and group like maps. ANOVAs and independent sample t-tests to test for map structure differences across demographic variables were statistically insignificant. As such, using vector-matrix operations, all 44 maps were aggregated into one cumulative, consensus map. This consensus map was then used to refine the posited theory and execute case scenario analyses to assess the value of forced labor slavery changes in proposed case scenario simulations.

Broadly, participants identified forced labor slavery as a distal outcome of marine fish stock declines, describing a process wherein declines intensify effort - increasing production costs. These increasing costs then incentivize the use of forced labor in response to narrowing profit margins, ultimately normalizing the use of forced labor as an economically rational decision. Case scenario analyses suggested if overfishing is not addressed, and marine stocks continue to decline, forced labor slavery in the fishing sector will continue to increase. Additionally, increases in forced labor slavery may increase stock declines. Proposed policy interventions to mitigate overfishing could reduce labor abuses in the sector. Therefore, the framework produced by the consensus map should guide more wide-scale, empirical testing of the relationship between fish stock declines and forced labor slavery and identify points-of-intervention for policy and fisheries management practices to mitigate social-ecological injustices in the fishing sector.

Publication Statement

Copyright is held by the author. User is responsible for all copyright compliance.

Rights Holder

Jessica L. Sparks


Received from ProQuest

File Format




File Size

183 p.


Environmental justice