Escalera Náutica. Balance para la conclusión de un megaproyecto de larga data en el Mar de Cortés, México

The Nautical Stairway constitutes a network of nautical scales with basic services and infrastructure for towable boats. The project would contribute to the regional development of the Gulf of California. This article analyzes the context of the megaproject as a tourism policy. The bibliography was compiled through search engines, books, technical and government reports. Three versions of the same project were found (1960-2017): Maritime Tourist Stairway, Nautical Stairway, and Sea of Cortez. Justifications, objectives, strategies, and scale distribution of the different versions of the project were compared. A timeline of institutional planning was carried out, as well as events associated with sectoral sexennial policies. The first version had 20 scales for nautical tourism. The second version, transformed into tourism policy, considered 24 scales, land, and air infrastructure to promote real estate development and golf courses. The last version, a 28 scales coastal tourism megaproject, failed, mainly due to pressure from tourism and environmental policies.

Patterns of Genomic Divergence and Signals of Selection in Sympatric and Allopatric Northeastern Pacific and Sea of Cortez Populations of the Sargo (Anisotremus davidsonii) and Longjaw Mudsucker (Gillichthys mirabilis)

Studying how isolation can impact population divergence and adaptation in co-distributed species can bring us closer to understanding how landscapes affect biodiversity. The Sargo, Anisotremus davidsonii (Haemulidae), and the Longjaw mudsucker, Gillichthys mirabilis (Gobiidae), offer a notable framework to study such mechanisms as their Pacific populations cross phylogeographic breaks at Point Conception, California, United States, and Punta Eugenia, Mexico, and are separated to those in the Sea of Cortez by the Baja California peninsula. Here, thousands of loci are genotyped from 48 Sargos and 73 mudsuckers using RADseq to characterize overall genomic divergence, and search for common patterns of putatively neutral and non-neutral structure based on outlier loci among populations with hypothesized different levels of isolation. We further search for parallels between population divergence and the total proportion of outliers, outlier FST distribution, and the proportion of outliers matching coding regions in GenBank. Statistically significant differentiation is seen across Point Conception in mudsucker (FST = 0.15), Punta Eugenia in Sargo (FST = 0.02), and on either side of the Baja California peninsula in both species (FST = 0.11 and 0.23, in Sargo and mudsucker, respectively). Each species shows structure using neutral and non-neutral loci. Finally, higher population divergence yields a more even distribution of outliers along their differentiation range but does not always translate into higher outlier proportions or higher rates in which outliers are matched to coding regions. If repeated in similar systems, observed genomic patterns might reveal speciation signatures in diverse networks of population isolation.