. Recent studies have shown that acoustic signals play an important role in turtle social behavior and reproduction. We recorded embryos and hatchlings of Lepidochelys kempii inside the nest and underwater in June 2016 in Playa Santander, Veracruz, Mexico, and detected 189 sounds that were classified into 6 types according to their aural and spectral characteristics. Our results show that acoustic communication appears to be widely used in all species of sea turtles in aquatic environments, probably because of the high efficiency of this signaling modality in water compared with air.

In the Rio Negro, the third-largest tributary of the Amazon, many turtle species have been important commercial and protein resources for centuries for populations of humans living in the region. For many years, this had been a sustainable activity, but nowadays the outlook for turtle populations in the Amazon is unfavorable due to increasing hunting pressure. Based on 20 yrs of conservation work in the Amazon, we report on the pressure faced by turtle populations in the area and report a sustainable chelonian exploitation alternative developed in the Rio Negro region. We describe the materials and the hand processing artisans use to transform natural resources into artworks. Based on this community program model, we discuss the current government support to local communities of the Rio Negro and provide insights on the application of this economic alternative to substitute for turtle commercialization in the Amazon. The outcomes of this manuscript have direct applications for environmental managers, nongovernmental organizations, and policymakers in Brazil and aim to call government and environmental managers to promote turtle conservation in the Amazon, securing economic safety for local communities.

There are only a few studies documenting acoustic communication in chelonians; here we provide additional evidence that sound plays an important role in the interchange of information in this group. We recorded 12 nests of Dermochelys coriacea during March 2012 at Barra de la Cruz Beach, Oaxaca, Mexico. Four types of sounds were identified from recordings of nests after 51 d of incubation; our results reinforce the idea that sounds are important to coordinate group behavior in turtles.

We studied reproductive parameters and noted predation of Phrynops geoffroanus nests along the Guaporé River of the Brazilian and Bolivian Amazon during the beginning of the falling water level season ( vazante ) in July 1989 and 2008. We searched for nests on the banks of the Guaporé River every morning navigating by outboard along the Guaporé River between Divisa sector state of Rondônia in Brazil and Versalles village, Department El Beni in Bolivia. We found 10 nests in 1989 and 46 nests in 2008. Clutch size ranged from 7 to 16 eggs and was larger in 2008. There was no relationship between egg size and nest size or the size of eggs between year 1989 and year 2008. The predation rate in 2008 was 89.1%, all depredated by the lizard Tupinambis teguxin. Habitat loss for the lizard may be creating habitat utilization shifting and increased turtle nest depredation rates.

Although turtles are well protected by laws in Brazil, the laws are not enforced in some places and ignored in others. Based on 15 years of work in the Rio Negro Basin, we describe the history of turtle exploitation in this region, comment on their current conservation status, and suggest practical conservation alternatives that are necessary to preserve stable populations.