Since late 2014, the Mexican Caribbean coast has periodically received massive, atypical influxes of pelagic Sargassum spp. (sargasso). Negative impacts associated with these influxes include mortality of nearshore benthic flora and fauna, beach erosion, pollution, decreasing tourism and high management costs. To understand the dynamics of the sargasso influx, we used Landsat 8 imagery (from 2016 to mid-2020) to record the coverage of sargasso in the sea off the Mexican Caribbean coastline, with a maximum reported in September 2018. Satellite image analysis also showed local differences in the quantity of beached sargasso along the coastline. Over the years, good practice for collection on the beach and for off-shore collection of sargasso have been established through trial and error, and the Mexican Government and hotel industry have spent millions of dollars on removal and off-shore detention of sargasso. Notwithstanding, sargasso also has various properties that could be harnessed in local industries. The stimulation of local industrial growth would offer alternatives to the dependence on tourism, as a circular economy, based on sargasso, is developed.

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Changes in ecological attributes as a result of anthropogenic activities and climatic forces can jeopardize biodiversity, so these potential impacts must be evaluated for conservation. Integrating the different components of a large ecosystem can, however, pose a methodological challenge. When evaluating the sensitivity of a system, the level of stress imposed by a threat and the system's ability to deal with pressures ultimately define its actual condition. The objective of this study was to assemble a spatially explicit quantitative approach for evaluating the ecological vulnerability of 2 sea turtle species (Eretmochelys imbricata and Chelonia mydas). We used a method that combined the use of an open source planning tool (Conservation Action Planning) and spatial multicriteria analysis to determine the total cumulative ecological vulnerability to multiple threats for each species individually and for both species combined. The spatially explicit outputs were supported by hard data and expert knowledge, including the cumulative ecological vulnerability of each species to multiple threats. For each species, we identified areas in the Gulf of Mexico where individual threats have a potential impact and also determined high vulnerability locations. This spatially explicit approach is important when assessing ecological vulnerability and risk, it is versatile and easily reproducible for other organisms, and can be an important tool in supporting the conservation and management of endangered species.

Marine turtles are globally endangered species that spend more than 95% of their life cycle in in-water habitats. Nevertheless, most of the conservation, recovery and research efforts have targeted the on-land habitats, due to their easier access, where adult females lay their eggs. Targeting the large knowledge gaps on the in-water critical habitats of turtles, particularly in the Large Marine Ecosystem Gulf of Mexico, is crucial for their conservation and recovery in the long term. We used satellite telemetry to track 85 nesting females from their beaches after they nested to identify their feeding and residency habitats, their migratory corridors and to describe the context for those areas. We delimited major migratory corridors in the southern Gulf of Mexico and West Caribbean and described physical features of internesting and feeding home ranges located mainly around the Yucatan Peninsula and Veracruz, Mexico. We also contributed by describing general aggregation and movement patterns for the four marine turtle species in the Atlantic, expanding the knowledge of the studied species. Several tracked individuals emigrated from the Gulf of Mexico to as far as Nicaragua, Honduras, and the Bahamas. This information is critical for identifying gaps in marine protection and for deciphering the spatial connectivity in large ocean basins, and it provides an opportunity to assess potential impacts on marine turtle populations and their habitats.