Half a century of rising extinction risk of coral reef sharks and rays.

Sharks and rays are key functional components of coral reef ecosystems, yet many populations of a few species exhibit signs of depletion and local extinctions. The question is whether these declines forewarn of a global extinction crisis. We use IUCN Red List to quantify the status, trajectory, and threats to all coral reef sharks and rays worldwide.

Regional variation in multiple paternity in the brown smooth-hound shark Mustelus henlei from the northeastern Pacific.

Multiple paternity (MP) in the brown smooth-hound shark (Mustelus henlei) was assessed in 15 litters (15 mothers and 97 embryos) collected in the northern Gulf of California of which 86.7% were sired by more than one male (i.e.

Between uncertainty and hope: Young leaders as agents of change in sustainable small-scale fisheries.

The path to sustainable small-scale fisheries (SSF) is based on multiple learning processes that must transcend generational changes. To understand young leaders from communities with sustainable SSF management practices in Mexico, we used in-depth interviews to identify their shared motivations and perceptions for accepting their fishing heritage. These possible future decision-makers act as agents of change due to their organizational and technological abilities.

Mitochondrial DNA genome evidence for the existence of a third divergent lineage in the western Atlantic Ocean for the bull shark (Carcharhinus leucas).

We report for the first time a highly divergent lineage in the Caribbean Sea for the bull shark (Carcharhinus leucas) based on the analysis of 51 mitochondrial DNA genomes of individuals collected in the western North Atlantic. When comparing the mtDNA control region obtained from the mitogenomes to sequences reported previously for Brazil, the Caribbean lineage remained highly divergent. These results support the existence of a discrete population in Central America due to a phylogeographic break separating the Caribbean Sea from the western North Atlantic, Gulf of Mexico and South America.

Identification of a nursery area for the critically endangered hammerhead shark (Sphyrna lewini) amid intense fisheries in the southern Gulf of Mexico.

Since the 1980s, there has been growing concern in the Mexican Atlantic regarding high catches of neonate and juvenile sharks in small-scale fisheries. Fishery-dependent data from 1993 to 1994 and 2007 to 2017 and fishers' ecological knowledge from 2017 were used to identify nursery areas for scalloped hammerhead, Sphyrna lewini, in the southern Gulf of Mexico. Catch records and fishing areas of neonates, YOYs, juveniles and adults of S.

Biodiversity and conservation of sharks in Pacific Mexico.

Mexico is home to a broad biodiversity of shark species, and more than half of the sharks in Mexican waters are distributed in the Mexican Pacific, with over 62 species recorded. This high biodiversity is the result of numerous and diverse marine and coastal environments, including the dynamic Mexican seas, where circulation and spatial variation of oceanic currents is complex, and the seasonal variation of isotherms can be substantial. In the Mexican Pacific we can distinguish some patterns of species distribution, with temperate water and subtropical species found in the northern regions, and tropical conditions and species found in the south.

Growth, productivity, and relative extinction risk of a data-sparse devil ray.

Devil rays (Mobula spp.) face intensifying fishing pressure to meet the ongoing international demand for gill plates. The paucity of information on growth, mortality, and fishing effort for devil rays make quantifying population growth rates and extinction risk challenging.

Population Structure and Seasonal Migration of the Spotted Eagle Ray, Aetobatus narinari.

Few studies have reported on the fine-scale population genetics of batoid species in the Atlantic basin. Here, we investigate the genetic diversity and population structure of the spotted eagle ray, Aetobatus narinari, sampled in the northeastern and southwestern parts of the Gulf of Mexico and in the northwestern Caribbean Sea. Samples were collected from 286 individuals sampled across 3 geographic localities.