Why Rules Fail: Institutional Roots of Non-Compliance in Mexico’s Small-Scale Shark Fishery

Abstract

Small-scale fisheries management is a critical challenge for global fisheries sustainability. This study diagnoses the institutional failures behind overexploitation and regulatory non-compliance in Mexico’s shark-cazón fishery (predominantly Rhizoprionodon terraenovae). Using the Institutional Analysis and Development (IAD) Framework and Ostrom’s Social-Ecological Systems (SES) approach, we assessed the catch series (1976–2014) and institutional robustness. Results show a 77% surplus over the Maximum Sustainable Yield (MSY), with an average catch of 51,417 tonnes per year against a biological limit of 29,040 tonnes. The diagnosis reveals undefined access limits, exclusively state-run monitoring, sanctions provided for in law but not applied participatorily, and the absence of local conflict-resolution mechanisms. These findings suggest that overexploitation is not an inevitable biological failure but the outcome of a command-and-control design that inhibits collective action and erodes rule legitimacy. This study contributes to the common-pool resource governance literature by extending Ostrom’s framework and Hønneland’s compliance model to a previously underrepresented Latin American elasmobranch context. Based on this diagnosis, we recommend transitioning toward polycentric governance—with nested community monitoring, effectively enforced graduated sanctions, and local conflict-resolution mechanisms—as a strategy for improving regulatory compliance in data-limited fisheries.

1. Introduction

The study of regulatory compliance in fisheries has been systematically addressed by Hønneland [1,2], who distinguishes between coercive mechanisms, based on state deterrence, and discursive mechanisms, based on perceived legitimacy and user participation in rule design. Compliance has traditionally been analyzed through economic rationality—fishers comply with rules when it is economically advantageous—but this approach has been challenged: empirical studies show that compliance is also shaped by personal morality, social norms, and the perceived legitimacy of the management system, even when deterrence is weak [2,3,4,5]. Hønneland [1,2] argues that the public-choice literature emphasizes coercive measures, while the emerging literature on cooperative action or co-management emphasizes legitimacy and discursive measures as more effective for securing compliance.

Owing to their intrinsic biological vulnerability—low fecundity, late maturity, and long life cycles—more than a third of shark and ray species currently face an overfishing-driven extinction risk [6]. In the field of common-pool resource management, Ostrom [7] demonstrated that user communities can self-organize to manage resources sustainably without coercive state intervention, in contrast to the prediction of Hardin’s [8] “Tragedy of the Commons.” Ostrom [7] identified eight design principles that characterize robust institutions for common-pool resource management. Among these principles, monitoring (Principle 4), graduated sanctions (Principle 5), and conflict-resolution mechanisms (Principle 6) correspond directly to the coercive and discursive dimensions of compliance proposed by Hønneland [1,2]. Cox [9], in a systematic review of 91 empirical studies, found that these principles are well supported empirically, particularly in fisheries and forestry case studies.

The applicability of these frameworks to small-scale fisheries has been validated in diverse contexts: in southern Sri Lanka, eight beach-seine fishing communities achieved 90.9% compliance by satisfying Ostrom’s modified design principles [10], while in Uganda the substitution of co-management mechanisms with military enforcement neither increased catches nor resolved fleet overcapacity [11]—evidence, from different directions, that regulatory compliance depends more on participatory institutional design than on the intensity of coercion (both cases are revisited in Section 4.1).

In Mexico, the shark-cazón fishery is an essential socioeconomic pillar, ranking tenth among the country’s 22 most important fisheries by catch volume, with an estimated annual average of 29,772 tonnes and an economic spillover of nearly 437 million Mexican pesos [12]. However, the sustainability of this resource is uncertain: total estimated catch (reported plus unreported catch) reached a critical average of 51,417 tonnes per year over the 1976–2014 period (Standard Deviation [SD] = 15,703 t; Coefficient of Variation [CV] = 31%), systematically exceeding biological safety limits [13]. The consolidated Maximum Sustainable Yield (MSY) for the shark-cazón complex is estimated at 29,040 tonnes, representing a catch surplus of 77% above biological safety limits [13]. To estimate total catch, Rodríguez-Castro [13] applied a correction factor of 1.913 derived from Cisneros-Montemayor [14], who documented that unreported catch in Mexican marine fisheries is substantial, equivalent to approximately 91.3% in addition to the official catch.

Mexico’s small-scale shark-cazón fishery (hereafter SSSF) has been managed predominantly under a centralized “command-and-control” model, a term coined by Holling [15] to describe the top-down management of natural resources that reduces ecosystem resilience and generates systemic failures. This model is formalized through the Norma Oficial Mexicana NOM-029-PESC-2006, Pesca responsable de tiburones y rayas. Especificaciones para su aprovechamiento [16], which establishes temporary closures, minimum catch sizes, fishing-gear restrictions, ten reproductive refuge zones, and a ban on shark finning ([16]; the regulatory detail is revisited in Section 2.4). However, Article 4.10 states that the Secretariat “may”—not “shall”—establish Regional Management Committees, and Article 8.1 assigns surveillance exclusively to federal authorities, without providing for community monitoring mechanisms [16].

The Carta Nacional Pesquera (CNP), in its 2022 and 2023 editions, classifies the Gulf of Mexico and Pacific shark fisheries as “exploited at their maximum sustainable level” [17,18]. However, this classification is based exclusively on reported-catch data, without incorporating unreported catch [13,14]. The Plan de Manejo Pesquero de Tiburones y Rayas del Golfo de México y Mar Caribe (published 9 June 2022) [19] represents progress by including components of fisheries administration, awareness-raising, research, and management, but it establishes no binding mechanisms for its implementation.

Despite this body of evidence, a relevant knowledge gap persists. On the one hand, the literature on fisheries compliance [1-3,5] and on the institutional design of common-pool resources [7,8] has been successfully applied to small-scale fisheries in contexts as diverse as Sri Lanka [10], Uganda [11], and Uruguay and Brazil [20]. On the other hand, the biophysical evidence of SSSF overexploitation in Mexico has been documented with quantitative rigor [13], but independently of any institutional diagnosis. To the best of our knowledge, no study integrates both bodies of literature for the SSSF—nor, more broadly, for an elasmobranch fishery in Latin America, a region where Ostrom’s framework has already been applied to bony-fish fisheries [20] but not, to the best of our knowledge, to a shark or ray fishery—linking biophysical evidence of overexploitation with a systematic diagnosis of its institutional causes, whether through Ostrom’s design-principles framework [7] or through Hønneland’s model of coercive and discursive mechanisms [1,2]. This disconnect between the biological diagnosis and the institutional diagnosis constitutes the knowledge gap this study seeks to close.

It is important to clarify the temporal scope of this integration: the biophysical diagnosis is based on a historical series ending in 2014, whereas the institutional diagnosis analyzes the regulatory framework in force in 2026 (NOM-029-PESC-2006, the Ley General de Pesca y Acuacultura Sustentables [LGPAS], the 2022–2023 CNP, and the Management Plan). This asynchronous comparison remains informative for two reasons: first, the institutional design diagnosed—non-territorial individual permits, the absence of operating regional committees, exclusively state-run surveillance—has not changed substantially since 2014, so the institutional diagnosis describes conditions that remain in force; second, indirect evidence postdating 2014 exists (a reported catch of 42,704 t in 2017, and maximum-exploitation classifications in the 2022–2023 CNP; Section 3.1) consistent with overexploitation not having been reversed. This asynchrony is discussed in greater detail in Section 3.1 and acknowledged as a limitation in Section 4.4.

This study contributes to the literature in three concrete ways: (a) it applies the Institutional Analysis and Development (IAD) Framework and the Social-Ecological Systems (SES) approach, together with Ostrom’s design principles, to the institutional diagnosis of a Latin American elasmobranch fishery, a geographic and taxonomic context underrepresented in this literature; (b) it integrates biophysical evidence (historical catch series and surplus over MSY) with a systematic institutional diagnosis of the regulatory corpus, linking two bodies of evidence that have so far been developed independently for the SSSF; and (c) it translates the institutional diagnosis into concrete, verifiable regulatory-reform recommendations, anchored in Ostrom’s design principles and Hønneland’s compliance model.

1.1. Problem Statement

Research questions. Based on the identified knowledge gap, this study is organized around one general research question and three specific research questions, integrating two complementary components: a quantitative diagnosis (the catch surplus over MSY, based on secondary data) and a qualitative diagnosis (content analysis of the regulatory corpus), consistent with the qualitative-dominant mixed design presented in Section 2.1.

General research question (GRQ): Why, despite having technically sound formal regulation—closures, minimum sizes, refuge zones, and a finning ban—does the SSSF in Mexico show a 77% catch surplus over the MSY [13], evidence of a disconnect between established rules and actual extraction practices?

Specific research question 1 (RQ1): Does the SSSF in Mexico constitute a common-pool resource (CPR), characterized by the attributes of high rivalry and difficulty of exclusion [7,21]?

Specific research question 2 (RQ2): To what extent does the SSSF’s current institutional design (formalized in NOM-029-PESC-2006) meet the design principles that the commons literature has identified as necessary for robust, sustainable institutions [7,9]?

Specific research question 3 (RQ3): Which compliance mechanisms—coercive or discursive, per Hønneland’s distinction [1,2]—predominate in the SSSF’s institutional design, and how do they relate to the observed level of compliance [3]?

Research hypotheses. As tentative answers to each of these questions, the following hypotheses are proposed. H1 has a different status from H2 and H3: it is a classificatory premise that enables application of the IAD framework (if the SSSF were not a CPR, Ostrom’s design principles would not be the pertinent analytical tool), whereas H2 and H3 are the study’s substantive hypotheses regarding institutional design and compliance mechanisms:

General hypothesis (GH): The SSSF’s current overexploitation in Mexico—evidenced by the 77% catch surplus over MSY [13]—is not an inevitable biological failure but the result of an institutional design that inhibits collective action and erodes rule legitimacy, trapping fishers in a social dilemma where regulatory compliance is costly and competition for the resource is high [7,8].

Hypothesis 1

(H1, classificatory premise, answer to RQ1). The SSSF constitutes a CPR of high rivalry and difficulty of exclusion, a condition that, in the absence of robust institutions, generates structural incentives toward overexploitation, analogous to the dynamic described by the tragedy-of-the-commons theory [7,8].

Hypothesis 2

(H2, answer to RQ2). Given that NOM-029-PESC-2006 was designed under a centralized command-and-control paradigm [15], compliance with the design principles of robust institutions is expected to be low, replicating patterns of partial non-compliance documented in other small-scale fisheries with centralized or transitioning governance [9,20].

Hypothesis 3

(H3, answer to RQ3). The SSSF’s regulatory system relies predominantly on coercive mechanisms (state surveillance, formal sanctions) and lacks discursive mechanisms (user participation, community monitoring, perceived legitimacy), which, according to Hønneland’s model [1,2] and Kuperan’s [3] empirical evidence, helps explain the low regulatory compliance and the resulting observed catch surplus.

Objectives. From these questions and hypotheses, the general objective and specific objectives of the study are derived:

General objective: We aim to analyze the SSSF’s institutional structure in Mexico using the Institutional Analysis and Development (IAD) Framework [22,23] and the Social-Ecological Systems (SES) approach [24,25] to identify the governance failures that explain the low level of regulatory compliance and the catch surplus over MSY in this small-scale fishery.

Specific objective 1 (corresponding to RQ1/H1): We aim to classify the SSSF as a common-pool resource by determining its attributes of rivalry and difficulty of exclusion.

Specific objective 2 (corresponding to RQ2/H2): We aim to assess the degree to which the current institutional design complies with Ostrom’s design principles for robust institutions [7].

Specific objective 3 (corresponding to RQ3/H3): We aim to diagnose the balance between coercive and discursive compliance mechanisms in NOM-029-PESC-2006 and its relationship with the observed catch surplus over MSY.

As an anticipated expectation—to be confirmed with the evidence presented in Section 3 and Section 4—we expect that fishery sustainability would be potentially attainable if management transitioned from a centralized model based exclusively on coercive mechanisms toward polycentric governance that integrates discursive compliance mechanisms: nested community–state monitoring (Principle 4), graduated sanctions (Principle 5), and local conflict-resolution mechanisms (Principle 6) [1,2,7].

1.2. Theoretical Framework

In quantitative research, theory traditionally serves to generate falsifiable hypotheses that the study seeks to confirm or reject through data analysis [26]. In qualitative research, by contrast, theory is not “tested” in a statistical sense but is adopted as a theoretical framework or interpretive lens that guides what to observe, how to code data, and how to make sense of the phenomenon studied [27]. Since the present study is based on a qualitative-dominant mixed design (QUAL → quan; Section 2.1), theory here fulfills both functions in a complementary manner: on the one hand, it generates the specific, quantifiable hypotheses set out in Section 1.1 (the SSSF’s classification as a CPR, the compliance score for the design principles, and the balance between coercive and discursive mechanisms); on the other, it functions as the interpretive framework that guides the qualitative content analysis of the regulatory corpus (NOM-029-PESC-2006, LGPAS, CNP, Management Plan). This dual function of theory—hypothesis generator and interpretive lens—is consistent with the principles of mixed-methods research, in which theory articulates and lends coherence to a design’s qualitative and quantitative components [28].

The theoretical framework guiding this study’s qualitative interpretation comprises two nested, complementary theories. The first and more general is the IAD Framework and the SES approach developed by Ostrom [7,22,23,24], which constitutes this study’s general theory: it provides the conceptual vocabulary (action situation, design principles, resource subsystems, resource units, governance, and users) used to interpret the SSSF’s overall institutional structure [25,29,30]. The second is Hønneland’s compliance model [1,2], which functions as a middle-range theory (in the sense of [31])—that is, a more narrowly scoped theory, nested within Ostrom’s general framework, that focuses specifically on interpreting users’ compliance or non-compliance behavior toward rules, distinguishing between coercive and discursive mechanisms. Both theories are applied jointly throughout Section 2, Section 3 and Section 4 of this manuscript: Ostrom’s theory structures the overall institutional diagnosis (Section 2.3, Section 2.4 and Section 2.5 and Section 3.2, Section 3.3, Section 3.4 and Section 3.5), while Hønneland’s theory specifically guides the interpretation of the action situation and the diagnosis of compliance mechanisms (Section 2.4 and Section 3.3).

2. Materials and Methods

2.1. Study Design and Analytical Rationale

This work is based on a synthesis of secondary biophysical and institutional evidence, organized as a qualitative-dominant mixed-methods research design (QUAL → quan, following the notation of [32]), structured in three operational phases: (i) biophysical diagnosis of the resource, (ii) analysis of the regulatory framework, and (iii) assessment of community governance. It is important to clarify the scope of this methodological designation: the quantitative component (historical catch series, MSY, unreported-catch correction factor) comes entirely from a secondary source [13], with no primary biophysical data collection by the authors; the qualitative component consists of documentary and content analysis—conducted by the authors—of the regulatory corpus (NOM-029-PESC-2006, LGPAS, CNP, Management Plan), following the procedures described by Krippendorff [33], whose coding judgments are quantified using an ordinal rubric (

Table 1. Assessment rubric for the design principles of robust institutions in Mexico’s shark-cazón fishery (adapted from [16,17]).

Design Principle	Value 0: Not Met	Value 1: Partially Met	Value 2: Met
P1. Defined boundaries (1A: resource boundaries; 1B: user boundaries)	De facto open access; no boundaries for users or the resource.	Federal permits exist, but there are no clear territorial boundaries or effective exclusion.	Geographic and user boundaries are clearly defined and respected.
P2. Local congruence (2A: congruence with local conditions; 2B: congruence between appropriation and provision)	Rules imposed externally without regard for local biology or culture.	Closures and minimum sizes exist, but do not match regional biological cycles.	Appropriation rules are strictly adjusted to local biophysical conditions.
P3. Collective choice (collective-choice arrangements)	No formal mechanisms exist through which users can participate in modifying operating rules.	Consultative or limited-participation mechanisms exist, with no binding authority over management decisions.	Most users affected by operating rules can participate directly, with binding authority, in modifying them.
P4. Monitoring (4A: monitoring by users; 4B: monitoring by parties accountable to users)	Total absence of surveillance or catch recording.	Sporadic monitoring carried out solely by external state agents.	Systematic monitoring carried out by the State and/or by users themselves.
P5. Graduated sanctions	No consequences for rule non-compliance.	A graduated sanctions scheme exists in general legislation, but is not operationalized in the fishery-specific standard nor applied participatorily; or sanctions are fixed and extreme and rarely applied.	Sanctions increase according to the severity and recurrence of the infraction.
P6. Conflict resolution	No mechanisms exist for settling disputes between users.	Conflicts are resolved through lengthy or costly administrative processes.	Local, rapid, low-cost mechanisms exist for resolving disputes.

Note: Principles P7 (minimal recognition of organizational rights) and P8 (nested enterprises) were not assessed because they require analysis at scales above the fishery’s operational level, exceeding this study’s scope.

) and Cohen’s kappa coefficient (Section 2.5). This design is therefore distinct from a mixed design involving primary qualitative and quantitative data collection by the researchers themselves: it is a triangulation of secondary sources combined with original documentary analysis.

This approach is consistent with the tradition of methodological synthesis in comparative institutional analysis of common-pool resources: Poteete [34] argue that no single method—neither the qualitative case study nor the quantitative model—is sufficient on its own to capture the complexity of shared-resource governance systems, and reference studies such as Cox [9] similarly combine qualitative case-study coding with aggregate quantitative analysis of compliance with Ostrom’s design principles [7].

Theoretically, the design is grounded in the IAD Framework and the SES approach of Ostrom, presented in Section 1.2, frameworks widely used for diagnosing small-scale fisheries [35,36].

In this study, method reliability is reinforced through source triangulation [37,38], contrasting the biological reference points and catch surplus reported by Rodríguez-Castro [13] with a content analysis of federal regulatory instruments, including NOM-029-PESC-2006 [16], LGPAS [39], the 2022 and 2023 editions of the CNP [17,18], and the Management Plan [19].

2.2. Data Collection and Information Sources

The research drew on secondary data from official sources and indexed scientific literature. The use of secondary data in institutional analyses of common-pool resources is well documented in the literature, particularly when studies focus on diagnosing regulatory frameworks and governance structures at the national or regional scale [19,35].

For the biophysical characterization, we used the historical catch series for the shark-cazón complex for 1976–2014, reconstructed and published by Rodríguez-Castro [13], which integrates 26 fishing areas across the Mexican Republic based on the CONAPESCA/SAGARPA Aquaculture and Fisheries Statistical Yearbooks (1976–2014). The reference parameters, specifically the MSY, were obtained from the same study, which estimated a consolidated MSY of 29,040 tonnes for Mexico using Srinivasan’s [40] empirical model. It is important to distinguish two uncertainty metrics reported by Rodríguez-Castro [13] that should not be confused: CV = 91%—the lowest among the three models compared, and hence the criterion used to select Srinivasan’s model [40]—describes MSY variability across the 26 fishing areas compared (national, oceanic, regional, and state)—that is, how much the MSY differs from one area to another—and was used as a model-selection criterion, not as a measure of precision for Mexico’s specific reference point. The latter’s precision is reported separately: using Monte Carlo simulation (10,000 iterations, best-fit uniform probability distribution), Rodríguez-Castro [13] estimated a 95% confidence interval for Mexico’s MSY of 28,830–29,240 tonnes, a narrow interval (±0.7% around the central value) indicating a precise estimate of the reference point used in this study.

To estimate total catch (reported catch plus unreported catch), Rodríguez-Castro [13] calculated a correction factor of 1.913 from total-catch and reported-catch figures estimated by Cisneros-Montemayor [14] for Mexican marine fisheries as a whole; the factor itself (the ratio of total catch to reported catch) is Rodríguez-Castro’s [13] own calculation, not the original source’s. This factor is based on a reconstruction of total Mexican catch (an average of 1,523,000 t per year, 1950–2010 period) and reported catch (796,000 t), which includes estimates of illegal catch (86,000 t), unreported legal catch (233,000 t), and discards (408,000 t) [14].

For the institutional and governance analysis, we conducted a systematic review of Mexico’s current legal corpus. This type of documentary analysis is the standard approach in studies applying Ostrom’s design principles at the national or regional policy level, where access to primary field data may be limited [9,35]. The analysis included the LGPAS, NOM-029-PESC-2006 [16], the 2022 and 2023 editions of the CNP [17,18], and the Management Plan [16].

2.3. Operationalizing the IAD and SES Frameworks: Classification as a Common-Pool Resource

To carry out the comprehensive characterization of the SSSF as a common-pool resource (CPR), we jointly operationalized the IAD and SES frameworks of Ostrom [24]. Operationalizing these frameworks follows the methodological guidelines established in the specialized literature, which recommend disaggregating the system into its component subsystems to facilitate diagnosis of critical interactions [34,41,42].

Following these criteria, the system’s components were systematically distributed and analyzed into four interconnected subsystems:

• Resource System (RS): defines the biophysical attributes and boundaries of the ecosystem inhabited by species of the cazón complex (predominantly Rhizoprionodon terraenovae), delimiting the CPR’s geographic and ecological boundaries [24,35].
• Resource Units (RU): quantifies available stock, landing volume, and the economic value of the annual catch. This component incorporates Rodríguez-Castro’s [13] MSY estimates.
• Governance System (GS): analyzes the legal structure and levels of decision-making. This covers the de jure operating rules established in NOM-029-PESC-2006 (temporary closures, minimum catch sizes, and fishing-gear restrictions), collective-choice rules (permit- and concession-allocation mechanisms, and the National Fisheries and Aquaculture Council as a national-level consultative forum, Art. 22, [39]), and the constitutional rules derived from Article 27 of the Constitución Política de los Estados Unidos Mexicanos (CPEUM), which grants the Nation original ownership of waters and the right to regulate, for the public benefit, the use of natural resources [43]—the direct foundation of the command-and-control paradigm operationalized by the LGPAS [7,22].
• Users (U): characterizes the behavior of the fishery’s key actors, including small-scale coastal and medium-offshore fishers, formally organized into cooperatives or dependent on independent permit holders.

Figure 1 synthesizes these four subsystems and their interactions within the broader social, economic, and political context, following the standard SES framework schema [24,25,29].

Determining the attributes of rivalry and exclusion (classification as a CPR). To determine whether the SSSF constitutes a common-pool resource, we followed the typology of goods developed by Ostrom [7] and Ostrom [44], which classifies resources according to two fundamental attributes: (a) difficulty of exclusion, defined as the cost of preventing potential users from accessing the resource; and (b) rivalry or subtractability, defined as the degree to which one user’s consumption of the resource reduces its availability for others [7]. These two attributes are the only ones that define a resource’s nature as a CPR [7]. Cox [21] reaffirms the central importance of social and biophysical boundaries as a defining criterion, noting that the combination of social boundaries defining who is inside and who is outside, and biophysical boundaries indicating which parts of the environment are accessible to those “inside,” is a way of defining environmental property rights.

In contrast to Ostrom’s [7] eight design principles, which assess institutional conditions for successful CPR management [9], the exclusion and rivalry attributes are diagnostic: they determine what type of resource is being analyzed, not how it should be governed. These two attributes are therefore the only ones relevant to classifying the SSSF as a CPR; the design principles are applied at a later stage (Section 2.5) to assess institutional robustness.

Determining rivalry (subtractability). To classify the SSSF as high-rivalry, three conditions derived from the literature were verified [7,9]: (a) the target species exhibit low fecundity, late maturity, and long life cycles [6], meaning each unit of extracted biomass carries a high replacement cost; (b) the historical catch series documents a persistent 77% surplus over MSY [13], evidence that extraction by some users reduces availability for others; and (c) the design of the access system—individual, non-territorial permits with no community quotas—creates the structural conditions for direct competition among permit holders over a shared stock, consistent with the “race for fish” behavior described by Hardin [8] for open-access resources.

This structural condition is grounded in six sources of documentary evidence, including two quantitative sources and one involving direct institutional acknowledgment: (i) analysis of the access legal framework (NOM-029-PESC-2006, Articles 4.3.2, 4.3.3, and 4.4.2.1) reveals that permits are individual and non-territorial, allowing multiple permit holders to fish in the same geographic areas without clear boundaries [16]; (ii) the CNP [17,18] does not document the existence of territorial use rights (TURFs) for the SSSF; (iii) the persistence of unreported catch (factor 1.913; [13], based on [14]) indicates that access is not effectively controlled; (iv) the absence of Regional Management Committees (Article 4.10 of NOM-029) implies there are no institutional spaces where permit holders can negotiate territorial limits or quotas among themselves; (v) the number of independent economic units sharing the same stock without territorial allocation is considerable—on the Gulf of Mexico and Caribbean Sea coast alone, the Management Plan documents 274 active permits covering 1580 small vessels and 17 medium-offshore vessels [19]—; and (vi) the fisheries authority itself institutionally acknowledges the absence of effort management: since 1993 no new shark-fishing permits have been issued for small vessels, and since 1998 none for larger vessels, a measure explicitly adopted “to avoid increasing existing fishing effort” [15]; moreover, the Management Plan itself includes a specific action line, “Managing fishing effort directed at sharks and rays in the Gulf of Mexico and Caribbean Sea” (Action Line 1.5), whose first actions consist of “assessing actual fishing effort” and “evaluating strategies for regularizing fishing effort based on an assessment of actual current effort” [19]—that is, sixteen years after NOM-029, the authority still lacks a reliable assessment of actual fishing effort or a mechanism for allocating access among users, which constitutes a direct institutional acknowledgment—not merely an inference by the authors—that access to the resource remains unordered. Added to this is evidence of spatial overlap: the Management Plan documents that, besides the targeted coastal fishery, at least four other fisheries (shrimp trawling, tuna longlining, grouper longlining, and finfish net/longline fishing) incidentally catch sharks and rays in the same geographic zones as the targeted fleet [19], evidencing multiple fleets with different gear and targets operating on the same resource without exclusive zoning.

It should be noted that, while this documentary and institutional evidence is substantially more robust than a simple legal inference, it still does not amount to a direct empirical measurement of competition among individual users (e.g., through trends in catch per unit effort against the number of active permit holders, systematic counts of documented conflicts between fleets, or direct surveys of users); this limitation is discussed in Section 4.4 and proposed as a future research line in Section 4.5. The presence of conditions (a) and (b), together with the structural, quantitative, and institutional evidence described in (c), confirms the resource’s high rivalry.

Determining difficulty of exclusion. To classify the SSSF as having difficulty of exclusion, three conditions derived from the literature were verified [7,9]: (a) surveillance and monitoring costs along the Mexican coastline (11,122 km) are prohibitively high for the State without community support; (b) the access legal framework (NOM-029-PESC-2006, Articles 4.3.2 and 4.3.3) grants individual permits with no clear territorial limits, allowing de facto access by unauthorized users [16]; and (c) evidence of unreported catch (factor 1.913, [13,14]) indicates persistent illegal, unreported, and unregulated (IUU) fishing [45]. The presence of these three conditions confirms the difficulty of exclusion.

The resulting classification (high rivalry and difficulty of exclusion) confirmed that the SSSF operates as a CPR, justifying the application of the IAD framework and the analysis of Ostrom’s design principles in the subsequent sections.

2.4. Diagnosis of the Action Situation and Regulatory Misfit

Modeling of the action situation—defined by Ostrom [7] as the social space where actors interact, make decisions, and generate outcome patterns—was carried out by assessing the centralized command-and-control management paradigm. The choice of this paradigm is justified on three grounds.

First reason (congruence with the actual institutional design). The SSSF in Mexico is formally managed under a centralized model, embodied in NOM-029-PESC-2006 [16]. This model is characterized by: (a) operating rules (closures, minimum sizes, fishing-gear restrictions) designed unilaterally by the federal authority; (b) exclusively state-run surveillance, assigned to the Secretariat of Agriculture, Livestock, Rural Development, Fisheries and Food (SAGARPA, today the Secretariat of Agriculture and Rural Development [SADER]), the Secretariat of the Environment and Natural Resources (SEMARNAT), and the Secretariat of the Navy (SEMAR) (Article 8.1, [16]); and (c) user participation in decision-making only on a discretionary basis (Article 4.10, [11]). Assessing the SSSF under this paradigm therefore describes the model that actually exists, not one imposed externally.

Second reason (alignment with Ostrom’s framework). Ostrom [7,24] proposes that analyzing an action situation requires identifying seven structural variables: participants, positions, potential actions, potential outcomes, control, information, and costs and benefits. The command-and-control paradigm allows these variables to be operationalized directly: the participants are the State (as regulator) and fishers (as users); control is exercised by federal authorities; information is asymmetric; and costs and benefits generate incentives that can be analyzed under the tragedy-of-the-commons framework [8].

Third reason (contrast with alternative models). Alternative paradigms exist—such as co-management, polycentric governance, or community-based management using territorial rights—that could be more effective for the SSSF, and that constitute this study’s proposal. However, these alternative models are not the object of diagnosis because they are not implemented in the SSSF; the current model must first be diagnosed to identify its failures, and alternatives proposed thereafter [7].

Following the methodology for analyzing institutional fit developed by Ostrom [7], the diagnosis was structured around three sequential analytical axes, selected because the empirical evidence available for the SSSF indicates that critical governance failures are concentrated in these three dimensions [13,16]:

• Analysis of rules on paper (de jure) vs. rules in use (de facto): the formal mandates of NOM-029-PESC-2006 (fishing-gear restrictions, refuge zones, and closure periods) were contrasted with the actual coastal practices documented along the coastline.
• Assessment of the command-and-control mechanism: we examined the fishery’s structural dependence on external State surveillance (the National Aquaculture and Fisheries Commission [CONAPESCA] and the Secretariat of the Navy [SEMAR]), measuring the asymmetry between official inspection capacity and actual fishing effort.
• Identification of perverse incentives: we characterized the adaptive behaviors of users who, in seeking to formally comply with regulations or evade them owing to a lack of local rule legitimacy, accelerate stock degradation (e.g., “fishing derbies” before a closure begins, or catch underreporting).

To systematize this diagnosis, qualitative data obtained from the regulatory corpus (NOM-029-PESC-2006, LGPAS, CNP 2022, CNP 2023, Management Plan) were examined using qualitative content analysis [33,46], contrasting each NOM-029 operating rule with the available evidence on its actual implementation. The procedure comprised two stages:

First stage (identification of operating rules). We extracted from NOM-029-PESC-2006 [16] the rules that directly regulate SSSF users’ behavior: (i) a finning ban (Article 4.2.1), (ii) protection of at-risk species (Article 4.2.2), (iii) spatial exclusion zones (Article 4.3.4), (iv) temporary refuge zones (Article 4.3.7), (v) fishing-gear limits (Articles 4.4.2.1, 4.4.2.3, 4.5.1), (vi) mandatory fishing logbooks (Articles 4.3.10.2–4.3.10.3), (vii) satellite monitoring (Article 4.3.10.4), and (viii) creation of Regional Management Committees (Article 4.10).

Second stage (qualitative examination and reporting). Each of these eight rules was qualitatively examined in light of three guiding criteria—its observed degree of dysfunctionality, its propensity to generate economic incentives contrary to conservation, and the feasibility of its implementation without community support—and the corresponding findings are reported narratively in Section 3.3. This exploratory, individual-rule-level analysis complements the formal quantitative assessment—using an ordinal rubric, double coding, and calculation of Cohen’s kappa coefficient [47]—applied specifically to the six Ostrom Design Principles (P1, P2, P3, P4, P5, P6), described in Section 2.5 and reported in Section 3.4, given that these principles constitute the level of institutional aggregation directly linked to the study’s hypotheses (Section 1.1).

Classification of Compliance Mechanisms Following Hønneland’s Model

As a complement to the three analytical axes described above, and following Hønneland’s [1,2] normative compliance model presented in Section 1.2 as a middle-range theory, each of the eight NOM-029-PESC-2006 operating rules identified in the first stage of this procedure, as well as the associated surveillance practices, were qualitatively classified into two non-exclusive categories: (a) coercive mechanisms, defined as those based on state deterrence—external surveillance, formal sanctions, restrictions unilaterally imposed without user participation—and (b) discursive mechanisms, defined as those based on perceived legitimacy and user participation in rule design or application—consultation, shared responsibility, community monitoring, local conflict resolution [1,2].

The classification was carried out through qualitative content analysis [45,46] on the same regulatory corpus used in Section 2.2 (NOM-029-PESC-2006, LGPAS, 2022–2023 CNP, Management Plan), examining for each rule: (i) who designs it (unilateral federal authority vs. participatory process), (ii) who monitors compliance (external state agent vs. users or community), and (iii) what type of consequence non-compliance carries (administrative sanction vs. local resolution mechanism). Coding was carried out independently by the same two coders described in Section 2.5 (the first author and a research assistant), following the same double-coding and disagreement-resolution procedure through a consensus session moderated by a third researcher. The results of this classification are reported narratively in Section 3.3 and interpreted in light of Hønneland’s model in Section 4.2 and Section 5.2, directly supporting the assessment of Hypothesis 3 (H3, Section 1.1).

2.5. Assessing Institutional Robustness: Compliance with Ostrom’s Design Principles

Institutional robustness was assessed through a contrast analysis between the current management model and Ostrom’s [7] design principles, using the compliance metric proposed by Cox [9] in his systematic review of 91 empirical studies on common-pool resource management. This study applied a three-stage prioritization process to select the principles for assessment, based on the study’s scope and data availability:

First stage (exclusion by scale of analysis). Principles whose operationalization requires analysis at higher scales (state, national, or international) exceeding this study’s scope were excluded: P7 (minimal recognition of organizational rights) and P8 (nested enterprises). P3 (collective-choice arrangements) was initially considered for this same exclusion category; however, analysis of the regulatory corpus revealed directly assessable evidence on this principle within the material itself—Article 4.10 of NOM-029-PESC-2006 (Regional Management Committees) and Article 22 of the LGPAS (National Fisheries and Aquaculture Council), both already used as narrative evidence in Section 3.3—so it was included in the formal quantitative assessment to avoid an exclusion the available evidence did not justify.

Second stage (assessability with available data). Of the remaining principles (P1, P2, P3, P4, P5, P6), all were verified as directly assessable using publicly available data: content analysis of NOM-029-PESC-2006 and the LGPAS, the historical catch series [13], and CNP assessments [17,18].

Third stage (validation against the literature). Systematic reviews of fisheries case studies have found that Principles P1, P2, P3, P4, P5, and P6 most frequently explain the success or failure of management in small-scale fisheries [9]. Empirical evidence also supports the importance of monitoring (Principle 4), graduated sanctions (Principle 5), and collective-choice arrangements (Principle 3) as key predictors of regulatory compliance in fisheries [1,2,3,7].

It is worth noting that these three selection criteria—scale of analysis, assessability with available data, and support in the literature—were defined and applied prior to the coding and score-assignment process described below, in order to avoid a post hoc selection of principles based on the results obtained.

As a result, six principles critical to the SSSF assessment were selected: defined boundaries (P1), local congruence (P2), collective-choice arrangements (P3), monitoring (P4), graduated sanctions (P5), and conflict resolution (P6). Each was assessed using a three-level ordinal scale (0: not met; 1: partially met; 2: met), whose operational definitions are presented in Table 1. Score assignment was validated through triangulation of the catch-surplus data [13] with analysis of NOM-029-PESC-2006 restrictions [16], the LGPAS [39], and CNP assessments [17,18].

Coding was carried out independently by two coders (the first author and a research assistant). To assess inter-coder reliability, we calculated Cohen’s kappa coefficient (κ) [47], defined as κ = (P₀ − P_e)/(1 − P_e), where P₀ is the proportion of observed agreement and P_e the proportion of agreement expected by chance. Agreement magnitude was interpreted using the Landis scale [48]: κ < 0.00 = poor; 0.00–0.20 = slight; 0.21–0.40 = fair; 0.41–0.60 = moderate; 0.61–0.80 = substantial; 0.81–1.00 = almost perfect. This double-coding procedure with third-party arbitration follows standard methodological recommendations for assessing and reporting inter-coder reliability in qualitative content-analysis research [49]. Disagreements were resolved through a consensus session moderated by a third researcher. Because this procedure was applied to a small set of six items (Principles P1, P2, P3, P4, P5, and P6), the resulting κ value (Section 3.4) should be interpreted as indicative rather than as a statistically robust-precision estimate; this limitation is revisited in Section 4.4. It bears emphasizing that this procedure constitutes an inter-coder reliability check on a defined regulatory corpus (NOM-029-PESC-2006, LGPAS, CNP, Management Plan), not a probabilistic sampling exercise over a population [50]; statistical generalization beyond the analyzed corpus is therefore not intended, and the kappa coefficient here serves a coding quality-control function, not a population-inference one.

Figure 2 synthesizes the complete methodological flow described in this section, from secondary-data collection to the assessment of Ostrom’s design principles.

3. Results

3.1. Biophysical Status of the Resource and Catch Surplus

Analysis of the historical production series (1976–2014) confirms that Mexico’s shark-cazón fishery is operating under a condition of persistent overexploitation [13]. The data show that, while the consolidated MSY for the shark-cazón complex is estimated at 29,040 tonnes, total catches (reported plus unreported) reached a critical average of 51,417 tonnes per year (SD = 15,703 t; CV = 31%). This differential in extracted biomass represents a catch surplus of 77% above biological safety limits [13].

The correction factor used to estimate total catch (1.913) was calculated by Rodríguez-Castro [13] from catch figures documented by Cisneros-Montemayor [14] for Mexican marine fisheries. These latter authors estimated Mexico’s total fishery catch for 1950–2010, obtaining an annual average of 1,523,000 tonnes, broken down into reported catch (796,000 t) and unreported catch (727,000 t); the latter is further disaggregated into unreported legal catch (233,000 t), illegal catch (86,000 t), and discards (408,000 t) [14]. Rodríguez-Castro [13] calculated the 1.913 factor as the ratio between total catch (1,523,000 t) and reported catch (796,000 t) from this source.

The magnitude of this surplus must be understood in the context of elasmobranch vulnerability in Mexico. Saldaña-Ruiz [51] assessed the relative vulnerability of 531 commercially important marine species in Mexico (98 invertebrates, 66 elasmobranchs, and 367 bony fish) using a productivity-susceptibility analysis (PSA), a semi-quantitative method for data-limited fisheries [52]. Results indicate that 29 elasmobranch species (44%) exhibit high vulnerability to fishing activity, a significantly higher proportion than observed for bony fish (39 species, 11%) and invertebrates [51].

This overfishing pattern is concentrated predominantly in Regions 2 (Gulf of California) and 5 (Tamaulipas, Veracruz, and Tabasco coast) of NOM-029-PESC-2006 [11], where artisanal and industrial fishing-effort pressure has exceeded the resilience capacity of slow-growing species such as the Atlantic sharpnose shark (Rhizoprionodon terraenovae). Rodríguez-Castro [13] reports this series’ catch only as aggregate period statistics (mean, standard deviation, and coefficient of variation; Section 2.2), without publishing disaggregated annual values, so it is not possible to formally assess the surplus’s temporal trend within this study; this limitation is revisited in Section 4.4. Nonetheless, indirect evidence exists that overexploitation persisted after 2014: the 2017 Aquaculture and Fisheries Statistical Yearbook [12]—cited by Rodríguez-Castro [13] themselves in their introduction—reports a catch (uncorrected for underreporting) of 42,704 tonnes for 2017, a figure that, on its own, without applying the 1.913 correction factor, already exceeds the reference MSY (29,040 t). Likewise, the CNP continues to classify the shark fishery as at maximum-exploitation status, both in its 2022 edition for the Gulf of Mexico and Caribbean Sea and in its 2023 edition for the Pacific ([17,18]; Section 3.2), and the closure regulatory scheme described in NOM-029 has not changed substantially since its publication in 2007. These indications, while not a substitute for an updated series, are consistent with the overexploitation condition diagnosed for the 1976–2014 period not having been reversed.

Figure 3 compares average annual catch with MSY across the seven fishing areas for which Rodríguez-Castro [13] reports both values explicitly, confirming that the catch surplus is not limited to the national aggregate but is consistently replicated at each level of geographic aggregation, including the above-mentioned Regions 2 and 5.

Table 2. Absolute and percentage differences between average annual catch and MSY, by fishing area (adapted from [13], Table 7).

Area	Average Catch (t/yr)	MSY (t/yr)	Absolute Difference (t/yr)	Surplus (%)
Mexico (national)	51,417	29,040	−22,377	−77%
Pacific Ocean	38,654	20,840	−17,814	−85%
Gulf of Mexico	15,737	14,540	−1197	−8%
Region 2 (Gulf of California)	22,664	14,330	−8334	−58%
Region 5 (Tamps./Ver./Tab.)	9202	8510	−692	−8%
Baja California	5781	4880	−901	−18%
Baja California Sur	5950	5510	−440	−8%

complements Figure 3 with the exact percentage-surplus figures by area, calculated by Rodríguez-Castro et al. [13] (Table 7).

Figure 4 geographically locates the six fishing regions established in Article 0.17 of NOM-029-PESC-2006 [16] used as the unit of analysis in this study, including Regions 2 and 5 where the largest catch surplus is concentrated.

3.2. Characterizing the Shark-Cazón Fishery as a Common-Pool Resource (CPR)

Applying the procedure described in Section 2.3, the SSSF was confirmed to possess the two critical attributes of a common-pool resource:

High rivalry. Confirmed because (a) target species exhibit low fecundity, late maturity, and long life cycles [6,51], magnifying the impact of each unit of extracted biomass; (b) the historical catch series documents a persistent 77% surplus over MSY [13]; and (c) the design of the permit system—individual, non-territorial, with no community quotas—creates the structural conditions for direct competition among permit holders over a shared stock. This condition is grounded not only in analysis of the access legal framework but in direct quantitative and institutional evidence: the Gulf of Mexico and Caribbean Sea Management Plan documents 274 active permits covering 1580 small vessels and 17 medium-offshore vessels competing without territorial allocation [19]; the freeze on new permits since 1993 (small vessels) and 1998 (larger vessels) was explicitly adopted “to avoid increasing existing fishing effort” [19]; and the Management Plan itself includes an action line dedicated to “assessing actual fishing effort” and “regularizing” that effort (Action Line 1.5, [19]), which constitutes an institutional acknowledgment—not merely an inference by the authors—that access to the resource remains unordered sixteen years after NOM-029’s publication. Added to this is the documented spatial overlap between the targeted coastal fleet and at least four incidental fisheries (shrimp, tuna, grouper, and finfish) operating in the same geographic zones [19] (see Section 2.3 and the limitations in 4.4).

Difficulty of exclusion. Confirmed because (a) surveillance and monitoring costs along the Mexican coastline (11,122 km) are prohibitively high for the State without community support; (b) the access legal framework (NOM-029-PESC-2006, Articles 4.3.2 and 4.3.3) grants individual permits with no clear territorial boundaries; and (c) evidence of unreported catch (factor 1.913) indicates persistent illegal, unreported, and unregulated (IUU) fishing [45].

The 2022 CNP classifies the Gulf of Mexico shark fishery as “exploited at its maximum sustainable level” [17], while the 2023 edition does the same for the Pacific [18]. However, these classifications are based exclusively on reported-catch data and on individual species-level assessments, not on the aggregate complex [13]. Agnew [45] estimated that global IUU catch ranges between 11 and 26 million tonnes per year, between 14% and 33% of reported global catch; by contrast, this data, reported by Rodríguez-Castro [13] and based on total catch, shows a 77% surplus over MSY for Mexico’s SSSF, consistent with the high rivalry and difficulty of exclusion documented here.

3.3. Diagnosis of the Action Situation and Rules in Use

The institutional analysis reveals that the “action situation”—defined by Ostrom [7] as the social space where actors interact, make decisions, and generate outcome patterns [29,30]—is shaped by a command-and-control design that produces the following outcomes [1,2]:

Perverse incentives. The system of individual permits, with no clear territorial boundaries or community quotas, incentivizes a “race for fish,” in which the rational fisher maximizes immediate catch given uncertainty about future resource availability [7,8]. This behavior is consistent with Hardin’s [8] prediction but contrasts with findings from empirical studies of small-scale fisheries that have achieved successful self-organization through robust institutions [10]. Kuperan [3] found that the legitimacy of the management system and fishers’ personal morality are predictors of compliance as important as economic deterrence.

Failures in operating rules. We identified a disconnect between collective-choice rules (federal concessions) and local operating rules [7,22]. The closures established in NOM-029-PESC-2006 and minimum catch sizes are perceived as external impositions, raising compliance costs and reducing the legitimacy of the governance system [2,3].

Refuge zones without effective monitoring. Article 4.3.7 of NOM-029 establishes ten refuge zones to protect reproduction and birthing processes, including the coastal zone off Playa Bagdad in Tamaulipas, Laguna de Términos in Campeche, and Espíritu Santo, Ascensión, and Chetumal Bays in Quintana Roo [16]. Gillnet use is prohibited in these zones from 1 to 30 June each year. However, the effectiveness of these zones depends critically on the existence of local monitoring (Ostrom’s Principle 4), which NOM-029 does not provide for.

Absence of Regional Committees. Article 4.10 of NOM-029 states that the Secretariat “may” (not “shall”) establish Regional or Sub-regional Management Committees. In practice, 16 years after its publication, these committees do not operate in most fishing regions. This absence of institutional spaces for fisher participation contradicts Ostrom’s Principle 3 (collective-choice arrangements), which holds that most individuals affected by operating rules must be able to participate in their modification [7,9]. This pattern repeats at the national scale: the LGPAS creates the National Fisheries and Aquaculture Council as an “intersectoral forum for support, coordination, consultation, agreement-building, and advisory services” (Art. 22, [39]), but limits it to a minimum annual meeting and an explicitly consultative role, with no binding authority over management decisions. The coincidence of this same design—discretionary, non-binding participation—at both hierarchical levels of the regulatory system (NOM-029 at the regional level, LGPAS at the national level) suggests that the disconnect between operating rules and collective-choice rules is not an isolated flaw in the standard but a structural feature of Mexico’s fisheries institutional design.

3.4. Assessment of Ostrom’s Design Principles

Following the procedure described in Section 2.5, score assignment was carried out independently by two coders, with the second coder (research assistant) unaware of the study’s specific hypotheses prior to coding, yielding a Cohen’s kappa coefficient of κ = 0.71 between the two; given the small number of coded items (n = 6 principles), this value is reported solely as indicative of the degree of agreement reached, without an associated confidence interval and without assigning it to a descriptive category on the Landis scale [48], whose precision is not sustainable at this sample size (see the limitation in Section 4.4). Disagreements were resolved through a consensus session moderated by a third researcher, following independent coding by both evaluators. Final scores are presented in

Table 3. Assessment of compliance with Ostrom’s Design Principles in Mexico’s shark-cazón fishery (adapted from [7,9]).

Design Principle	Score (0–2)	Justification
P1. Defined boundaries	0	De facto open access. No clear territorial boundaries exist (permits are individual, non-territorial), nor are there mechanisms for effectively excluding unauthorized users.
P2. Local congruence	1	Temporary closures and minimum sizes are established under NOM-029, but they do not fully match regional biological cycles or account for variations in traditional fishing practices across the six regions defined in Article 0.17 of the standard.
P3. Collective choice	0	No formal mechanisms were identified through which SSSF users can participate in modifying operating rules. Article 4.10 of NOM-029 states that the Secretariat “may”—not “shall”—establish Regional Management Committees; in practice, 16 years after publication, these committees do not operate in most fishing regions (Section 3.3). At the national level, the LGPAS (Art. 22) creates the National Fisheries and Aquaculture Council, but limits it to a consultative role with no binding authority and a minimum annual meeting requirement.
P4. Monitoring	0	Monitoring is carried out exclusively by external agents (CONAPESCA/SEMAR), with limited coverage. Article 8.1 of NOM-029 assigns surveillance exclusively to federal authorities. No community or peer monitoring exists.
P5. Graduated sanctions	1	The LGPAS ([38], Arts. 132–138) does provide for a graduated sanctions scheme (fines across four levels indexed to the Unit of Measure and Update [UMA] according to infraction severity, doubling upon recurrence). However, this scheme (a) is not specifically operationalized in NOM-029-PESC-2006 for the SSSF; (b) is designed and administered unilaterally by the Secretariat, with no user participation in its graduation or application, as Ostrom’s Principle 5 requires; and (c) shows no evidence of systematic application to the SSSF, with permit suspension or revocation—the catalog’s most extreme sanction under Art. 133—being the one documented in practice, generating de facto impunity. The system therefore exists in the general legal design but not in its fishery-specific implementation.
P6. Conflict resolution	0	No local, rapid, low-cost institutional spaces were identified for resolving disputes between users (e.g., between small-scale fishers and the medium-offshore fleet). NOM-029 makes no provision for conflict-resolution mechanisms.
Total	2/12 (17%)

. Out of a total of 12 possible points, Mexico’s SSSF scored 2 out of 12 (approximately 17%); this score should be interpreted as a quantified qualitative synthesis for communication purposes, not as a decimal-precision psychometric measurement.

Figure 5 graphically represents the scores from Table 3: none of the six principles assessed reaches the level of full compliance (2), with four of them—defined boundaries (P1), collective choice (P3), monitoring (P4), and conflict resolution (P6)—in total non-compliance.

The diagnosis for each principle is detailed below:

Boundaries of users and the resource (Principle 1, score 0): not met. No clear boundaries exist defining who has the right to extract the resource in specific zones, facilitating open access [7,21]. Permits are individual and non-territorial, which incentivizes the race for fish [7,8]. By contrast, successful self-governed fisheries—such as beach seines in Sri Lanka—have shown that defining fishing territories, eligibility rules, and inter-community access rules effectively resolves the exclusion problem [10].

Congruence between rules and local conditions (Principle 2, score 1): partially met. Although temporary closures and minimum sizes exist, they do not adjust to regional variations in the reproductive cycles of target species. NOM-029 defines six fishing regions based on environmental factors and species predominance, but operating rules are uniform within each region, despite ecological and social heterogeneity [29].

Collective choice (Principle 3, score 0): not met. No formal mechanisms were identified through which the majority of users affected by operating rules can participate in their modification, a condition central to Principle 3 [7,9]. Article 4.10 of NOM-029 leaves the establishment of Regional Management Committees to the Secretariat’s discretion (“may,” not “shall”), and these committees do not operate in most fishing regions 16 years after the standard’s publication (Section 3.3). At the national level, the National Fisheries and Aquaculture Council (LGPAS, Art. 22) offers a consultative space, but with no binding authority over management decisions and a minimum annual meeting requirement, replicating the same pattern of discretionary participation at both hierarchical levels of the regulatory system.

Monitoring (Principle 4, score 0): not met. Monitoring is carried out exclusively by external agents (the State), with limited coverage and no mechanisms for community or peer monitoring. Article 4.3.10.4 of NOM-029 establishes a Satellite Monitoring and Localization System for larger vessels, but this system is administered exclusively by the Secretariat, with no user participation. McGinnis [30] notes that effective monitoring requires that monitors be the users themselves or be accountable to them.

Graduated sanctions (Principle 5, score 1): partially met. Unlike NOM-029-PESC-2006, which does not provide for a differentiated sanctions scheme, the LGPAS ([39], Arts. 132–138) does establish a graduated catalog of seven sanction types—from formal warnings to permit suspension or revocation—and fines scaled across four levels indexed to the Unit of Measure and Update, according to infraction severity, with the fine amount doubling upon recurrence (Arts. 136, 138). However, this scheme is designed and administered unilaterally by the Secretariat, with no user participation in its graduation or application, and no evidence was found of its systematic application to the SSSF; documented practice points to the catalog’s most extreme sanction (permanent permit suspension), rarely applied, generating de facto impunity [1]. This disconnect between a graduated legal design (de jure) and a non-graduated, non-participatory application (de facto) is consistent with empirical evidence that graduated sanctions are more effective at sustaining compliance when their application is predictable and perceived as legitimate by users [2,3].

Conflict resolution (Principle 6, score 0): not met. No local, rapid, low-cost institutional mechanisms were identified for resolving disputes between users. Conflicts between the small-scale fleet and the medium-offshore fleet, as well as between coastal fishers and permit holders, remain subject to lengthy, costly administrative processes [29]. This finding is consistent with what has been documented in small-scale fisheries in Uruguay and Brazil, where conflicts between artisanal fishers and government agencies represent significant barriers to adaptive co-management [20].

3.5. Synthesis of the Institutional Diagnosis

Analysis of the six design principles assessed reveals a very low level of compliance (17% of the maximum possible score). This diagnosis indicates that Mexico’s SSSF lacks most of the institutional attributes that the commons literature has identified as necessary for successful self-organization and sustainability of common-pool resources [7,9].

In particular, the absence of defined boundaries (P1), collective-choice arrangements (P3), community monitoring (P4), and conflict-resolution mechanisms (P6), together with the deficient—non-participatory and non-operationalized for the SSSF—application of the graduated sanctions scheme that the LGPAS does provide for (P5), generates an action situation in which individual incentives align with overexploitation, trapping fishers in a social dilemma similar to that described by Hardin [8]. This finding is consistent with the observation that top-down management approaches are rarely associated with successful common-pool resource management, while co-management regimes combining elements of common and state property show better outcomes [7,10,20].

The Management Plan [19] represents progress by including components of fisheries administration, awareness-raising, research, and management. However, the Plan contains 113 actions across 24 action lines with no binding implementation mechanisms and no clear responsibilities with defined deadlines [19]. The Plan, while necessary, is therefore not sufficient to correct the institutional failures diagnosed here [29,30].

4. Discussion

This study’s objective was to analyze the institutional structure of Mexico’s shark-cazón fishery using the IAD Framework and Ostrom’s SES approach, to identify the governance failures that explain the 77% catch surplus over the Maximum Sustainable Yield. The main finding is that the results presented in Section 3 are consistent with the interpretation that this overexploitation is not an inevitable biological failure but the consequence of a command-and-control institutional design that disconnects de jure rules from de facto practices. These findings are next interpreted in light of prior literature (4.1), their theoretical (4.2) and fisheries-policy (4.3) implications are derived, and the study’s limitations (4.4) and future research lines (4.5) are discussed.

4.1. Interpretation in the Context of Prior Studies

Our findings coincide with the global trend documented by Dulvy [6], who identifies overfishing as the leading threat to elasmobranch extinction, being the sole threat for 67.3% of threatened species. However, beyond the biological dimension, recent studies have pointed to a lack of effective governance as a determining factor in the collapse of small-scale fisheries worldwide.

In a global study of reef sharks published in Nature, MacNeil [53] analyzed more than 15,000 video stations across 371 reefs in 58 nations and found that shark decline was strongly related to socioeconomic conditions such as the size and proximity of the nearest market, poor governance, and human population density. The authors identified that opportunities for shark conservation include shark sanctuaries, closed areas, catch limits, and the absence of gillnets and longlines, underscoring the importance of institutional design for elasmobranch conservation.

In a comparative study of small-scale fisheries in Uruguay and Brazil using Ostrom’s design principles, Trimble [20] identified structural barriers very similar to those documented in our SSSF: protracted conflicts between artisanal fishers and government agencies, as well as between small-scale and larger-scale sectors—exactly the same conflicts we document in the SSSF between the coastal fleet and the medium-offshore fleet. These authors found that, although both cases partially complied with seven of the eleven design principles modified by Cox [9], they failed to meet four critical principles, including the same ones we identify in our study: defined boundaries and monitoring.

The relevance of Ostrom’s design principles for diagnosing small-scale fisheries has been validated across multiple geographic contexts. Deepananda [10] demonstrated, in eight beach-seine fishing communities in southern Sri Lanka, that community institutions meeting the modified design principles achieve high compliance (90.9%) and have essentially avoided the tragedy of the commons. This study found that allocating fishing rights based on residential-proximity rights, clearly defining fishing territories, and having eligibility and inter-community access rules effectively resolve the exclusion problem. By contrast, our SSSF lacks these attributes, which explains the persistence of overexploitation.

More recently, Partelow [34] documented exponential growth in the use of the Social-Ecological Systems framework since 2014, particularly in studies of fisheries, forestry, and water-resource management, with concentration in North America and Europe but a growing number of studies in Latin America and Asia. Our study contributes to this literature by applying the SES framework to an elasmobranch fishery in Mexico, a context underrepresented in the international literature.

Uganda’s case offers an instructive contrast from a different direction. Mpomwenda [11] documented that, in the Nile perch fishery of Lake Victoria, replacing co-management mechanisms with a coercive military intervention neither increased catches nor resolved fleet overcapacity. Unlike our case—where the institutional failure stems from the near-total absence of effective coercive and discursive mechanisms—the Ugandan case shows that intensifying coercion alone, without accompanying discursive mechanisms, likewise fails to guarantee compliance or resource sustainability. Both cases, read together, support the central interpretation of Hønneland’s [1,2] model: neither the absence of coercion (our case) nor its unilateral intensification (Uganda) is sufficient; it is the balance between coercive and discursive mechanisms, not the magnitude of coercion alone, that explains regulatory compliance.

4.2. Implications for Compliance Theory and Polycentric Governance

This study’s findings contribute to three central debates in the literature on common-pool resource governance and regulatory compliance.

First implication: the need to distinguish between coercive and discursive compliance mechanisms. Hønneland’s [1,2] model distinguishes between coercive mechanisms (based on deterrence) and discursive mechanisms (based on legitimacy and rule acceptance). Our diagnosis shows that NOM-029 relies almost exclusively on coercive mechanisms: state surveillance, formal sanctions, and satellite monitoring. However, the absence of discursive mechanisms—user participation in rule design, community monitoring, local conflict-resolution mechanisms—erodes the system’s legitimacy and encourages non-compliance. Kuperan [3] argued that the legitimacy of the management system is as important a predictor of compliance as economic deterrence, and our results support this conclusion.

Second implication: the importance of community monitoring as an alternative to state surveillance. Cox [9] divided Ostrom’s Principle 4 into two subcomponents: 4A (monitoring by users) and 4B (monitoring by parties accountable to users). Our diagnosis shows that the SSSF meets neither subcomponent. The fisheries-compliance literature has consistently documented that community monitoring is more effective and less costly than exclusive state-surveillance systems [2,3,7]. Hatcher [4] found that trust in authorities and perceived fairness are key factors for voluntary compliance, and these factors can only develop when users participate in monitoring and rule enforcement.

Third implication: the need to move toward polycentric models. Ostrom [54] argued that polycentric governance systems—multiple decision-making centers at multiple levels—are more resilient than centralized systems. McGinnis [29,30] developed the concept of “networks of adjacent action situations” as an analytical basis for understanding polycentric governance. Our diagnosis shows that the SSSF operates under a highly centralized system, in which the federal fisheries authority (CONAPESCA) is the sole formal decision-making center, in contrast to the polycentric model that theory associates with greater institutional resilience. This theoretical divergence translates into concrete policy recommendations in Section 4.3.

4.3. Implications for Fisheries Policy in Mexico

First implication: NOM-029 requires structural reform. NOM-029 contains technically sound operating rules (closures, minimum sizes, refuge zones, a finning ban), but lacks the institutional attributes needed for effective implementation. Our diagnosis suggests that reform should include: (a) mandatory—rather than discretionary, as under the current Article 4.10—establishment of Regional Management Committees; (b) establishing community monitoring mechanisms with fisher participation; (c) implementing a graduated sanctions system with community participation; (d) creating local, rapid, low-cost mechanisms for conflict resolution; and (e) defining territorial fishing boundaries, possibly through Territorial Use Rights for Fishing (TURFs) for cooperatives, directly addressing the defined-boundaries failure (Principle 1) diagnosed in Section 3.4.

Second implication: The CNP should incorporate unreported catch into its assessments. The 2022 and 2023 CNP editions classify the shark fishery as “exploited at its maximum sustainable level” based exclusively on reported-catch data [17,18]. However, our analysis shows that this classification is misleading because it does not incorporate unreported catch (factor 1.913, [13,14]). We recommend that future CNP updates incorporate correction factors for unreported catch and assess not only biophysical indicators but also institutional indicators, following Ostrom’s design principles.

Third implication: The Management Plan needs binding implementation mechanisms. The Management Plan for the Gulf of Mexico [19] contains 113 actions across 24 action lines but establishes no binding mechanisms for their implementation. We recommend creating a Management Committee with real authority, allocating specific budgets for each action line, and defining compliance indicators with verifiable deadlines.

Fourth implication: The LGPAS needs to operationalize its own participation and sanction provisions. The diagnosis of Principles 3 and 5 (Section 3.3 and Section 3.4) reveals that the LGPAS already contains, on paper, institutional elements that NOM-029 lacks: a graduated sanctions scheme by severity and recurrence (Arts. 132–138) and a national participation forum, the National Fisheries and Aquaculture Council (Art. 22). The problem is not the absence of these provisions but that none of them has been operationalized for the SSSF or applied in a binding or participatory manner. We recommend: (a) expressly regulating, in NOM-029 or its reformed equivalent, application of the LGPAS’s graduated sanctions scheme to the SSSF, with graduation criteria specific to this fishery; (b) granting the National Fisheries and Aquaculture Council, or a technical committee derived from it, binding—not merely consultative—authority over shark and ray management decisions; and (c) increasing the Council’s minimum meeting frequency (currently annual) to allow closer oversight aligned with the timing of fisheries management decisions.

Fifth implication: The political feasibility of these reforms faces identifiable barriers. The experience of the past 16 years with Article 4.10 of NOM-029—which enables but does not require the establishment of Regional Committees (Section 3.3)—illustrates that a legal mandate’s existence does not guarantee its implementation. At least three factors constitute identifiable obstacles: (a) the limited budgetary and operational capacity of federal fisheries authorities (CONAPESCA/SADER) to decentralize monitoring and sanctioning functions; (b) possible resistance from sectors with interests in the regulatory status quo, particularly the medium-offshore fleet, which might perceive devolving authority to regional committees as a loss of regulatory uniformity or control over resource access; and (c) the absence of short-term political incentives for reforms whose benefits—stock recovery—materialize over multi-year horizons, while their transition costs (training, institutional negotiation) are immediate. The polycentric-governance literature recognizes that transitioning from centralized systems requires not only formal rule redesign but sustained investment in local capacities and political will to transfer real—not merely consultative—authority to users [30,54]. Without this explicit recognition, the recommendations formulated here risk repeating the pattern this very study documents: technically sound rules on paper, without the institutional conditions for their effective application.

4.4. Study Limitations

Methodological limitations. Institutional analysis via the IAD framework and assessment of the design principles depend on qualitative interpretation of current legal frameworks and available literature. Although a double-coding procedure with Cohen’s kappa calculation (κ = 0.71) was implemented to reduce subjectivity, this coefficient was calculated on a small set of six items, so it should be interpreted only as indicative of the degree of agreement reached between coders and not as a statistically precise estimate; the qualitative nature of the analysis further implies that other researchers might assign different scores to the assessed principles. Likewise, the coding rubric (Table 1) was developed by the authors themselves based on Ostrom [7] and Cox [9], with no independent content-validation process (e.g., review by an external panel of fisheries-governance experts) or documented pilot test, an additional limitation beyond inter-coder reliability. Additionally, the exclusion of Principles 7 and 8 for reasons of analytical scale (Section 2.5) means that the compliance score obtained (17%) reflects only the operational subset of principles assessed; it cannot be ruled out that future analysis of these principles at higher scales could qualify—in either direction—the overall institutional-robustness diagnosis. Finally, this study is based on secondary data (regulatory documents, published catch series, published literature) and does not include primary fieldwork (fisher interviews, participant observation, focus groups) that could enrich the diagnosis of rules in use versus de jure rules.

Catch-data limitations. The catch series used [13] covers the 1976–2014 period and has been corrected for unreported catch using a national average factor (1.913; [13], based on [14]), which may not adequately reflect regional variation in underreporting levels. Underestimating unreported catch could result in underestimating the true surplus over MSY, meaning our 77% surplus could be conservative. Likewise, the source reports the series only as aggregate period statistics (mean, standard deviation, coefficient of variation), without publishing disaggregated annual values; this prevents assessing whether the catch surplus has increased, decreased, or remained stable across the series’ 39 years, and no publicly available update of the catch series using an equivalent methodology exists for the post-2014 period, further limiting assessment of recent trends; this limitation is addressed directly in Section 4.5 (Line 6).

Limitations in measuring rivalry (resource competition). Characterizing the SSSF as high-rivalry is grounded in documentary, quantitative, and institutional evidence (the design of individual, non-territorial permits, the number of active permit holders and vessels, the historical freeze on permits for effort-related reasons, and the fisheries authority’s own explicit acknowledgment that actual effort has neither been assessed nor regularized; [19]), but not in a direct empirical measurement of competition among individual users. An even more robust demonstration would require, for example, analysis of catch-per-unit-effort (CPUE) trends against the number of active permit holders over time, systematic counts of documented conflicts between fleets or fishing zones, evidence of “fishing derbies” in monthly catch data prior to closures, or direct surveys of users regarding their perception of competition. Such data were not publicly available with the temporal and geographic breakdown required for this study, so, despite the strength of the institutional evidence presented, the characterization should be interpreted as a strongly supported structural condition, consistent with theory [7,8], rather than as a direct individual-user-level measurement. Future studies should address this limitation directly (see Section 4.5, Line 1).

Scope limitations. This study focuses on the fishery’s operational level and the collective-choice level (regional committees and the National Fisheries Council). Although the direct constitutional foundation of the command-and-control paradigm is identified (Article 27 of the CPEUM, Section 2.3), no comparative constitutional-law analysis or exhaustive review at the constitutional level is conducted, which exceeds this work’s scope. Likewise, the study focuses exclusively on the SSSF and does not include a comparative analysis with other Mexican fisheries that might have more robust institutional arrangements (e.g., spiny lobster in Yucatán, Gulf corvina in the Upper Gulf of California); this limitation is addressed directly in Section 4.5 (Line 4).

4.5. Future Research Lines

Line 1: Direct measurement of resource competition and assessment of social capital. Studies are needed that empirically measure the rivalry inferred in this work, through analysis of catch-per-unit-effort (CPUE) series against the number of active permit holders, systematization of documented conflicts between fleets or fishing zones, and analysis of monthly catch patterns around closure onsets (“fishing derbies”). These analyses should be complemented with mixed-methods field studies (semi-structured interviews, focus groups, social-network analysis) to gauge SSSF fishers’ willingness toward co-management arrangements.

Line 2: Participatory design of community monitoring systems. We propose a pilot community-monitoring project in one or two representative SSSF communities (for example, in Region 2 of the Gulf of California or Region 5 of the Gulf of Mexico), including fisher training, standardized sampling protocols, and independent validation of community-generated data.

Line 3: Bioeconomic modeling of governance scenarios. We recommend integrating bioeconomic models that incorporate the transaction costs of different governance models (exclusive state surveillance vs. nested community monitoring vs. mixed systems).

Line 4: Comparative analysis with successful Mexican fisheries. Mexico has examples of co-management that should be analyzed in contrast to the SSSF, such as the spiny lobster fishery in Yucatán, Gulf corvina in the Upper Gulf of California, and the Fishing Refuge Areas established between 2017 and 2018.

Line 5: Incorporating local ecological knowledge (LEK) into stock assessment. Future research should document and systematize SSSF fishers’ local ecological knowledge regarding population trends, reproductive seasons, and nursery areas, complementing official catch series.

Line 6: Updating and annually disaggregating catch series. We recommend that fisheries authorities, in collaboration with researchers, publish the total catch series disaggregated by year (not only as period statistics) and update the reconstruction beyond 2014, using an unreported-catch correction methodology comparable to that of Cisneros-Montemayor [14], ideally differentiated by region. This would, for the first time, allow formally assessing whether the surplus over MSY has increased, decreased, or remained stable, and would replace the single national correction factor with regionally sensitive estimates.

5. Conclusions

5.1. Answer to the Research Question and Hypothesis Contrast

The general question guiding this study (Section 1.1) was: why, despite technically sound formal regulation, does Mexico’s shark-cazón fishery (SSSF) show a 77% catch surplus over the Maximum Sustainable Yield (MSY)? The evidence presented in Section 3 and Section 4 is consistent with, and supports, the general hypothesis (GH): overexploitation is not an inevitable biological failure but the result of an institutional design that inhibits collective action and erodes rule legitimacy [7,8]. Because this is a documentary-analysis and secondary-data-synthesis design, with no experimental manipulation or direct measurement of the proposed causal mechanisms, this and the following formulations should be understood as interpretive support for the evidence, not as causal confirmation in a strict statistical sense.

The evidence likewise supports the three specific hypotheses set out in Section 1.1. Hypothesis 1 (H1)—the classificatory premise that the SSSF constitutes a common-pool resource of high rivalry and difficulty of exclusion—was verified through the classification of both attributes (Section 3.2), justifying application of the IAD/SES framework. Hypothesis 2 (H2)—that compliance of the institutional design with Ostrom’s design principles would be low—is supported by a score of just 17% (2/12; Section 3.4, Figure 5), with critical failures in defined boundaries (P1), collective choice (P3), monitoring (P4), and conflict resolution (P6). Hypothesis 3 (H3)—that the regulatory system relies predominantly on coercive mechanisms and lacks discursive mechanisms—is supported by the evidence presented in Section 3.3 and interpreted in Section 4.2 in light of Hønneland’s model [1,2].

5.2. Return to the Theoretical Framework: The IAD/SES Framework and Hønneland’s Compliance Model

The theoretical framework presented in Section 1.2 posited a dual function for theory: generating quantifiable hypotheses and, simultaneously, guiding qualitative interpretation of the regulatory corpus. Both functions proved productive. The IAD and SES frameworks of Ostrom [7,22,23,24] provided the conceptual vocabulary—action situation, design principles, RS-RU-GS-U subsystems (Figure 1)—that enabled organizing a systematic institutional diagnosis for a Latin American elasmobranch fishery, a context where this framework had not previously been applied, helping to fill the geographic gap identified in Section 1.

Hønneland’s [1,2] compliance model, as a middle-range theory nested within the general framework, specifically guided interpretation of the action situation: the evidence is consistent with the predominance of coercive over discursive mechanisms—exclusive state surveillance without community participation, sanctions lacking effective graduation in practice—helping to explain the low compliance observed, extending the validity of this model, originally developed for Norwegian fisheries, to a Latin American small-scale institutional context.

5.3. Implications for Fisheries Policy in Mexico

As argued in Section 4.3, the findings translate into concrete recommendations for reforming NOM-029-PESC-2006, the LGPAS, the CNP, and the Management Plan: territorial fishing boundaries (possibly through Territorial Use Rights for Fishing), regional adjustment of closures and minimum sizes, community monitoring, graduated sanctions with community participation, and local conflict-resolution mechanisms, together with reforming Article 4.10 of NOM-029 to make the establishment of Regional Management Committees mandatory—not discretionary—with binding authority, and operationalizing the sanction (Arts. 132–138) and participation (Art. 22) provisions that the LGPAS already provides for but does not apply.

5.4. Final Reflection

Based on the institutional diagnosis presented here—subject to the methodological and scope limitations described in Section 4.4—we suggest that SSSF sustainability would be attainable by transitioning from an exclusively coercive centralized model toward polycentric governance [54] that grants fishers an active role in monitoring, the application of graduated sanctions, and decision-making; this recommendation derives from the applied theoretical framework and the comparative literature (Section 4.1), not from a direct causal test within this study. As Ostrom [7] noted, common-pool resource users can overcome collective-action dilemmas when they can communicate, establish credible rules, and enforce those rules among themselves. National fisheries policy must evolve from a purely ichthyological approach to a social-ecological systems approach to ensure the sustainability of elasmobranchs and the communities that depend on them.