Understanding how institutions affect or shape fisheries performance is an important part of providing practical insights for the development of management strategies that promote sustainable fishing. In the Gulf of California there is widespread evidence of declines in fish stocks upon which small-scale fisheries depend and these declines are largely attributed to policy failures. Using methods commonly used in social sciences, I investigated the formal and informal rules regulating resource use by smallscale fishers from two fishing communities in the Northern Gulf of California (NGC), Bahía de Kino and Bahía de los Ángeles, Mexico, and their effects on fisheries sustainability. Some of the main results are summarized below: a) The percentage of fishers holding fishing rights and actually using them to report and commercialize catch was quite small in both communities (fishing rights are usually in the hands of absentee operators). b) Current policies and policy changes do not reach the fishers in a direct and formalized way in any of these communities, and these policies are shaped with no participation of local fishers. c) Current policy tools show poor performance in practice and have been ineffective (at the moment) in promoting sustainable fishing practices by fishery stakeholders. Neither community has been able to manage their resources sustainably. Results also suggest some potentials that could lead to more sustainable fishing practices in both communities: d) The presence of informal rights (fishers' sense of ownership) over the fishing grounds in the surroundings of their home communities. Generally, local fishers do not conform to or enforce the individual boundaries of the fishing rights they hold (or work under), but they do care about and defend an area that they perceive as belonging to their community as a whole, particularly when there are "outsiders" coming in. e) The presence of strong support from the fishers for implementing improved regulatory measures for local fisheries. Specific recommendations for each case study are provided with the aim of enhancing rules legitimacy and improving management outcomes.

The Miocene to Pliocene southern Bouse Formation preserves a record of depositional environments immediately prior to and during integration of the Colorado River to the Gulf of California. Uncertainty over Bouse paleoenvironments obscures our understanding of the timing and magnitude of regional uplift, as well as the conditions and processes that were active during integration and early evolution of the Colorado River. Prior studies over the past 20 years have concluded that the southern Bouse Formation accumulated in chain of lakes isolated from the ocean. Sedimentologic analyses presented here aid interpretation of depositional environments and provide evidence for a strong tidal influence on deposition, consistent with a marine interpretation of other prior studies. This interpretation places a critical constrain on the elevation of these deposits at ca. 5 Ma, and suggests post-Miocene uplift of the Lower Colorado River corridor. This thesis includes previously published coauthored material.

Recurrent crises due to overexploitation of fishery resources have been among the biggest natural resource management failures of the 20th century. This problem has both biological and socio-political elements and understanding of human dimensions represents a key step toward the formulation of sound management guidelines for natural resources. One of the strategies proposed to understand human dimensions is through the use of local knowledge. Integrating local peoples' knowledge with scientific research and data analysis, could aid in the design of fisheries management strategies in a cost-effective and participatory way.I introduce an approach to incorporating fishers' local knowledge at a large, regional scale. I focused on the spatial and temporal distribution of fishing activities from 17 communities in the Northern Gulf of California, Mexico. Participatory mapping (maps produced by local fishers) through a rapid appraisal (survey methodology) were used to identify the spatial and temporal dimensions of fishing activities. A geographic information system was used to generate 764 map layers used for a preliminary analysis of rapid-appraisal spatial data. Post-survey workshops with fishers were organized to facilitate an internal validation of spatial information using geographic information system software. We characterized the information based on fishing communities, fishing methods, target species and spawning sites. We also applied spatial analysis techniques to understand the relative importance and use of fishing grounds, fishing seasons and the influence that fishing communities have over the region. This dissertation addressed the problem of integrating the human dimensions of small-scale fisheries using geospatial tools and local knowledge (LK) - data collection, integration, internal validation, analysis and access - into a multidisciplinary research to support decision making in natural resource planning for small-scale fisheries management and conservation in the Northern Gulf of California, Mexico.

I use microchemistry in fish otoliths to test the hypothesis that diverting Colorado River flow from reaching the Gulf of California has impacted two endemic fish: the threatened gulf Corvina, (Cynoscion othonopterus) and the endangered totoaba (Totoaba macdonaldi). The oxygen and carbon stable isotope ratios in otoliths help to reconstruct conditions of the environment during key life history stages before and after the damming and diverting the Colorado River. The δ¹⁸O in otoliths illustrate that both C. othonopterus and T. macdonaldi seek out brackish habitat provided by the Colorado River during their early life history. The δ¹⁸O of C. othonopterus otolith have a strong negative correlation with Colorado River flow. I found that previously published relationships between otolith δ¹⁸O and ambient temperature along with δ¹⁸O of the water are sufficient to predict ranges of expected δ¹⁸O values for T. macdonaldi in the field. The δ¹⁸O in pre-dam T. macdonaldi otoliths show significant divergence from modern T. macdonaldi otoliths’ values, indicating that these fish used the brackish waters of the Colorado River estuary. The δ¹³C in T. macdonaldi otoliths has a significant proportion of its δ¹³C derived from diet. Pre-dam T. macdonaldi juveniles have a significantly different diet, which reflects that the Colorado River estuary had higher productivity before diversion of the river. Lastly, T. macdonaldi grew faster before the dams and in association with Colorado River flow measured by the δ¹⁸O.

Understanding the level of biological connectivity among populations of harvested species is an important step towards establishing fisheries management and conservation guidelines. Many marine benthic resources present a complex metapopulation structure in which separate subpopulations of sessile post-larval individuals are connected through larval dispersal. The extent to which these subpopulations are linked is termed connectivity and can have different patterns and implications. Therefore, good management practices require tools that explicitly acknowledge this complexity across scales.I investigated the level of connectivity in a commercially important benthic species, the rock scallop (Spondylus calcifer), in an ecologically sensitive region in the NE margin of the Gulf of California, Mexico. My approach involved the development of a predictive coupled biological-oceanographic model (CBOM), which simultaneously incorporated key oceanographic and biological features. I validated CBOM outputs by means of two different techniques: population genetics analysis and measurements of spat abundance on artificial collectors.In order to infer the planktonic period of S. calcifer larvae to be used as an input for the model, I studied the early life history of the species under laboratory conditions. I estimated that the minimum period for larvae of S. calcifer to reach the settlement is approximately 15 days after fertilization. In addition to providing information useful for the model, this study produced information about the experimental conditions under which spawning induction and rearing of the species can be successful.I found strong connectivity along the study region (covering approximately 300 km of coastline). Sampled localities showed low levels of genetic structure, suggesting the existence of two subtly differentiated genetic populations. Both genetic and CBOM spatial scales of connectivity are in agreement suggesting that, on average, connectivity between subpopulation decreases when the geographic distance between them is >100 km.This study provides a multidisciplinary approach to evaluate the direction, magnitude and spatial scale of larval dispersal and connectivity, with implications for fisheries management and conservation in the study region. More broadly, it provides a baseline for future studies on coastal connectivity at various spatial scales of interest in the Gulf of California and beyond.

We developed a set of hypervariable microsatellite markers for the Pacific red snapper (Lutjanus peru), an economically important marine fish for small-scale fisheries in the west coast of Mexico. We performed shotgun genome sequencing with the 454 XL titanium chemistry and used bioinformatic tools to search for perfect microsatellite loci. We selected 66 primer pairs that were synthesized and genotyped in an ABI PRISM 3730XL DNA sequencer in 32 individuals from the Gulf of California. We estimated levels of genetic diversity, deviations from linkage and Hardy-Weinberg equilibrium, estimated the frequency of null alleles and the probability of individual identity for the new markers. We reanalyzed 16 loci in 16 individuals to estimate genotyping error rates. Eighteen loci failed to amplify, 16 loci were discarded due to unspecific amplifications and 32 loci (14 tetranucleotide and 18 dinucleotide) were successfully scored. The average number of alleles per locus was 21 (+/- 6.87, SD) and ranged from 8 to 34. The average observed and expected heterozygosities were 0.787 (+/- 0.144 SD, range 0.250-0.935) and 0.909 (+/- 0.122 SD, range 0.381-0.965), respectively. No significant linkage was detected. Eight loci showed deviations from Hardy-Weinberg equilibrium, and from these, four loci showed moderate null allele frequencies (0.104-0.220). The probability of individual identity for the new loci was 1.46(-62). Genotyping error rates averaged 9.58%. The new markers will be useful to investigate patterns of larval dispersal, metapopulation dynamics, fine-scale genetic structure and diversity aimed to inform the implementation of spatially explicit fisheries management strategies in the Gulf of California.

Holocene sediments from intertidal and shallow subtidal zones in Bahia la Choya, Mexico exhibit significant differences based on their mineralogical content, constituent composition, textural parameters, and foraminiferal assemblages. The intertidal sediments are characterized by low calcium carbonate content, being dominated by quartz, and are moderately well sorted and coarse skewed with a fine mean grain size {Mz = 2.73 phi}. Total numbers {living and dead} of benthonic Foraminifera per ml of sediment are relatively low (12/ml) in the intertidal zones. In contrast, the subtidal sediments are characterized by high calcium carbonate content, being dominated by molluscan shell fragments, and are poorly sorted and nearly symmetrically skewed with a medium mean grain size {Mz = 1.41 phi}. Total numbers of benthonic Foraminifera per ml of sediment are relatively high (52/ml) in the subtidal zone. The analysis of bioerosion intensity indicates that differences in susceptibility to bioerosion exist not only at the subordinal level but also at the generic level of Foraminifera. Overall rates of test destruction are rapid, apparently due to the combination of biological, chemical, and physical processes. The experimental determination of test characteristics which correlate with settling or entrainment enables the delineation of foraminiferal morphotypes which are most likely to be transported. Test settling velocity is mostly affected by test size and weight. Movement threshold velocity is, also, mostly affected by test size, weight, and shape, in addition to the nature of the substrates and initial test orientation. Foraminifera from siliciclastic environments exhibit relatively low settling and movement threshold velocities. Thus, taxa from siliciclastic settings are more likely to be transported by currents than are those from carbonate environments, which show a wide range of settling and movement threshold velocities. Such information may be utilized to distinguish between autochthonous and allochthonous microfossil assemblages in the stratigraphic record.

I address the emergence, governance, and effects of marine reserve efforts in the Gulf of California, Mexico, emphasizing a community-based marine reserve network established by the commercial diving sector of Puerto Peñasco, Sonora. This network emerged as a means to manage benthic resources in rocky reefs, primarily rock scallop (Spondylus calcifer) and black murex snail (Hexaplex nigritus). My study also provides an analysis of growth, reproductive ecology, and management of both species.I show that local cooperation to manage fisheries commons incorporating the use of marine reserves can emerge rapidly. Furthermore, this cooperation can be sustained in a fishery spanning no more than two generations, effectively avoiding a local "tragedy of the commons". A blend of social group characteristics, fishers' ecological knowledge and participation in monitoring, and relatively rapid ecological response of the system can play key roles in reinforcing cooperation.I provide evidence of rapid effects of reserves on adjacent fisheries via larvae dispersal. Visual censuses revealed that density of young rock scallop (individuals recruited since reserve establishment) had increased by up to 40.7% within coastal reserves and by 20.6% in fished sites in only two years. Changes were also evident for black murex, with more than a three-fold increase in the density of juveniles within fished sites. These effects, however, were spatially-constricted, evident only for the northern portion of the reserve network. These empirical findings are more indicative of a reserve effect rather than other confounding factors and are consistent with field oceanography data (release of satellite-tracked drifters) and outputs from larvae dispersal models.Finally, I show that just as cooperation can emerge, it can rapidly fall with cascading effects to the system's resilience, particularly amidst threats to social capital and pressure from outside the community. I conclude that even when community-based reserves are effective within the biophysical and local social context, their long-term efficacy will rely on the system's capacity to control access and will demand the institutional capacity to do so. In Mexico this implies, at the least, the government's formal recognition of community-based initiatives and a means to give viability to these efforts.

<p>The need for effective multi-level governance arrangements is becoming increasingly apparent because of the high functional interdependencies between biophysical and socioeconomic factors in the realm of natural resource governance. Such arrangements provide a basis for the exchange, discussion, and deliberation of information, knowledge, and data across diverse user groups and entities. Multi-level governance is operationalized by using a microinstitutional analysis that links decision-making arenas across three distinct levels: operational, collective-choice, and constitutional. Within this context, I argue that the effectiveness and success of actors' participatory processes across these three levels depend on the amount of social capital among actors within the governance system. I assessed the concept of social capital using two different models: (1) a structural approach focused on resources embedded within an individual's network, and (2) a combined structural-cultural approach that incorporates various aspects of group membership with relations of trust, rules, and norms. To explore the effects of social capital on participatory processes related to the implementation and management of natural resources, I analyzed different small-scale fisheries governance regimes from the Gulf of California, Mexico. I collected data using surveys (n=371), interviews (n=82), and participant observation techniques conducted among the residents of four small-scale fishing communities that live adjacent to marine protected areas along the Baja California, Mexico, peninsula. Data analysis included both quantitative (logit regression model), and qualitative (narrative analysis) approaches. Overall, my results suggest that both social capital models reveal the multidimensional nature of social capital where none of its individual types form a consistent and statistically significant relationship with the six outcomes that I measured. However, these types are related in different ways to fishers engagement in participatory processess across the three levels. The extent of fishers' engagement in participatory processess across different levels was not high. Qualitative analysis revealed that participatory processes related to fisheries conservation and management, although present do not reach their full potential and are stymied by a historical context and a lack of general participatory culture.</p> / Dissertation

The provision of freshwater, particularly in urbanizing arid regions facing increased variability in precipitation patterns due to climate change, is one of the greatest challenges. Desalination--the conversion of seawater or brackish water to potable water--offers a potentially "limitless" supply of this vital resource. The preference for desalination, as an innovative, supply-side water augmentation option is gaining traction worldwide, including in northwestern Mexico. In arid regions, where water is a limiting factor to increased production and growth and nearly every drop of water is contested, a new technology that augments water supplies is likely to engender vast social, economic, institutional, and environmental transformations. Through an in-depth study of water management in the context of global climate change in northwestern Mexico, this dissertation examines the factors that lead to the adoption of desalination technology and assesses how the technology affects the communities where it is implemented. In seeking to understand the (potential) transformations and complex imbrications of this technology within the socioecological system in which it operates, four themes have emerged, including: 1) The best path towards improved water management is through investments in both infrastructure and institutions (i.e., governance); 2) Despite the real and urgent need to address the negative impacts of climate change on water resources, desalination should be considered as a "last resort"; 3) While desalination can increase water security at certain scales, it also introduces new vulnerabilities; and 4) While discursively, Mexico's water policy embraces principles of contemporary environmental governance (i.e., decentralization, public participation, and sustainability), these principles have yet to be fully implemented in practice. Policy recommendations include integrating land use and water planning, improving monitoring and regulation of groundwater extraction, increasing capacity building within water and planning agencies, and pre-conditioning desalination (or other supply-side water infrastructure projects) upon the successful implementation of a range of water conservation and system efficiency measures. Without such measures, increased water availability is likely to encourage additional growth, rather than resource conservation. Specific findings and contributions of this dissertation to the field of human-environment geography are discussed at the end of chapter two and in the appended articles.