The aerobic oral and cloacal bacterial microbiota and their antimicrobial resistance were characterized for 64 apparently healthy sea turtles captured at their foraging grounds in Ojo de Liebre Lagoon (OLL), Baja California Sur, Mexico (Pacific Ocean) and the lagoon system of Navachiste (LSN) and Marine Area of Influence (MAI), Guasave, Sinaloa (Gulf of California). A total of 34 black turtles (Chelonia mydas agassizii) were sampled in OLL and eight black turtles and 22 olive ridley turtles (Lepidochelys olivacea) were sampled in LSN and MAI, respectively from January to December 2012. We isolated 13 different species of Gram-negative bacteria. The most frequently isolated bacteria were Vibrio alginolyticus in 39/64 (60%), V. parahaemolyticus in 17/64 (26%) and V. cholerae in 6/64 (9%,). However, V. cholerae was isolated only from turtles captured from the Gulf of California (MAI). Among V. parahaemolyticus strains, six O serogroups and eight serovars were identified from which 5/17 (29.4%) belonged to the pathogenic strains (tdh+ gene) and 2/17 (11.7%) had the pandemic clone (tdh+ and toxRS/new+). Among V. cholerae strains, all were identified as non-O1/non-O139, and in 4/6 (66%) the accessory cholera enterotoxin gene (ace) was identified but without virulence gene zot, ctxA and ctxB. Of the isolated V. parahaemolyticus, V. cholerae and V. alginolyticus strains, 94.1%, 33.4% and 100% demonstrated resistance to at least one commonly prescribed antibiotic (primarily to ampicillin), respectively. In conclusion, the presence of several potential (toxigenic) human pathogens in sea turtles may represent transmission of environmental microbes and a high-risk of food-borne disease. Therefore, based on the fact that it is illegal and unhealthy, we discourage the consumption of sea turtle meat or eggs in northwestern Mexico.

Blood parameters provide an excellent tool to evaluate the health status of wildlife. However, there are few studies about health parameters of sea turtles in Mexico. For olive ridley turtles (Lepidochelys olivacea), no information was available to establish the health baseline for the species. The objective of this study was to establish reference blood biochemistry values for olive ridley turtles in the northern Sinaloa foraging area. Between 2013 and 2015, 82 olive ridley turtles were captured. Body condition index (BCI) presented a mean of 1.46 ± 0.14 (1.17–2.02) that categorized the population with excellent body condition; in addition, 99% of the turtles captured had a good physical appearance. Blood was collected for biochemistry analysis from 60 turtles. Significantly higher values of total protein, albumin, A/G ratio (albumin/globulin) and PCV (packed cell volume or hematocrit) were observed in adult when compared to subadult turtles. On the other hand, no significant differences were found when females and males were compared. Based on the BCI, physical assessment, and blood parameters, and compared to other sea turtle species, olive ridley turtles in northern Sinaloa were considered in excellent health. To the best of our knowledge, this is the first study to establish normal blood biochemistry values of foraging olive ridley turtles in northern Sinaloa.

Trophic position and niche width are fundamental components of a species’ ecology, reflecting resource use, and influencing key demographic parameters such as somatic growth, maturation, and survival. Concepts about a species’ trophic niche space have important implications for local management and habitat protection, and can shed light about resilience to changing climate for species occurring over broad spatial scales. For elusive marine animals such as sea turtles, trophic niche is challenging to study, and researchers often rely on other metrics, such as isotopic niche, as a proxy. Here, stable isotope analysis (δ¹³C and δ¹⁵N values) was conducted on bulk skin tissue of 718 green turtles (Chelonia mydas) distributed among 16 foraging areas in the eastern Pacific from the USA to Chile, a range spanning ~10,000 km. Compound‐specific nitrogen isotope analysis of amino acids (CSIA‐AA) was applied to 21 turtles among seven sites. Isotopic niche space was determined via Bayesian ellipse area (BEA) and convex hull area (CHA) analyses of bulk isotope values, which were also used along with amino acid δ¹⁵N values to determine trophic position (TP). Substantial variability in bulk tissue δ¹³C and δ¹⁵N values was found within and among sites, and amino acid δ¹⁵N values confirmed this was largely due to spatial differences in baseline nitrogen isotopic compositions, but also to a lesser extent from TP differences among the green turtle foraging populations. Isotope niche space varied among sites, influenced by the diversity of prey types and relative input of terrestrial‐ vs. marine‐derived nutrients; BEAs were the most suitable measurement of isotopic niche space due to the larger influence of outlying values with the CHA approach. Amino acid isotope‐derived TP estimates that accounted for local habitat conditions (e.g., mixed seagrass/macroalgae diet) performed the best among several approaches; TP ranged from 2.3 to 3.6, which indicates an omnivorous diet for most populations. In addition to providing additional spatial resolution for δ¹³C and δ¹⁵N isoscapes in the eastern Pacific, especially in coastal habitats, this study further establishes CSIA‐AA as an effective tool to study the trophic ecology of sea turtles across a variety of food webs and habitats.

Loggerhead turtles (Caretta caretta) are characterized by their transoceanic migratory patterns in the North Pacific Ocean, as individuals of this species originating from nesting beaches in Japan are known to forage along the Baja California Peninsula (BCP), Mexico. The nearshore waters of BCP serve as important foraging habitat for growth and development; however, the implementation of appropriate management strategies has been hindered by the paucity of data on the biology and distribution of the species, particularly for juveniles during their developmental migrations. We report for the first time the occurrence and distribution of loggerhead turtles in Sinaloa, Mexico, in the southernmost portion of the Gulf of California.

Olive ridleys (Lepidochelys olivacea) are the most numerous sea turtle species worldwide and also locally along the Pacific coast of Mexico. Published data on their distribution and nesting abundance along the coast of Nayarit and northern Jalisco, Mexico are, however, scarce. Here we describe the current extent of conservation activities and the history of efforts to protect sea turtles along this 394-km stretch of coastline. We found that 110 km (of the total of 394 km) are monitored by 18 sea turtle conservation programs, which in 2015 accounted for 43.2% of the total shoreline. Olive ridley sea turtle nesting was encountered on all monitored beaches. Our use of hatchery-protected nests as a measure of nesting levels is undoubtedly an underestimate of overall nesting in the region; however, it nevertheless provides a baseline of current nesting intensity in sites under conservation. Bahia de Banderas presented the highest nesting levels in the study area with 46.4% (3742 +/- 904; mean +/- SD) of the total protected nests (8073 +/- 547) while only representing 14.2% (15.4 +/- 3.8 km) of the total area monitored (109.6 +/- 4.5 km). The results provided here represent a valuable baseline upon which future research and assessments can be built when analyzing the sea turtle conservation progress in the region.