DNA barcode analysis of the endangered green turtle (Chelonia mydas) in Mexico1.

Technological and analytical advances to study evolutionary biology, ecology, and conservation of green turtles (Chelonia mydas) are realized through molecular approaches including DNA barcoding. We characterized the usefulness of COI DNA barcodes in green turtles in Mexico to better understand genetic divergence and other genetic parameters of this species. We analyzed 63 sequences, including 25 from green turtle field specimens collected from the Gulf of Mexico and from the Mexican Pacific and 38 already present in the Barcode of Life Data Systems (BOLD). A total of 13 haplotypes were identified with four novel haplotypes from the Pacific Ocean and three novel haplotypes from the Atlantic Ocean. Intraspecific distance values among COI gene sequences by two different models were 0.01, demonstrating that there is not a subdivision for green turtle species. Otherwise, the interspecific distance interval ranged from 0.07 to 0.13, supporting a clear subdivision among all sea turtle species. Haplotype and total nucleotide diversity values of the COI gene reflect a medium genetic diversity average. Green turtles of the Mexican Pacific showed common haplotypes to some Australian and Chinese turtles, but different from the haplotypes of the Mexican Atlantic. COI analysis revealed new haplotypes and confirmed that DNA barcodes were useful for evaluation of the population diversity of green turtles in Mexico.

Comparison of the blood biochemical values of foraging and nesting Olive Ridley turtles (Lepidochelys olivacea) from Sinaloa, Mexico.

Our study aimed to establish reference values for nesting females and compare them with those previously reported to understand olive ridley turtles' health status and contribute to long-term health assessment and monitoring in foraging and nesting areas from the state of Sinaloa, Mexico. In August and September 2018, morphometric data and biochemical profiles were collected from 33 nesting olive ridley turtles from Ceuta Beach Sanctuary (CBS) and 14 foraging female turtles captured at the foraging site, Navachiste Marine Area (NMA). Nesting turtles sampled had greater CCL (65.86 ± 1.70 cm) than those from the foraging area (61.54 ± 1.22) (p < 0.05). Regarding biochemical profiles, post-nesting turtles had higher packed cell volume (PCV), albumin, blood urea nitrogen (BUN), cholesterol, triglycerides, and calcium than turtles from the foraging area (p < 0.05). Phosphorus levels were higher in foraging turtles than in nesting turtles (p = 0.001), while the remaining parameters showed no significant differences. The present study describes for the first time the blood biochemical values of nesting turtles from the Ceuta Beach Sanctuary in southern Sinaloa, Mexico, similar to those of foraging turtles from the north of the state. The significant differences observed between the two analysis groups may be due to the energy reserves and reproductive and nesting activity of the nesting turtles, so the blood biochemistry values described in this study can be used as a standard reference blood value for the olive ridley turtle population of Sinaloa, Mexico.

Trace elements concentration in blood of nesting Kemp's Ridley turtles (Lepidochelys kempii) at Rancho Nuevo sanctuary, Tamaulipas, Mexico.

The concentrations of trace elements including As, Zn, Cu, Se, Pb, Hg and Cd, were determined in the blood of nesting Kemp's ridley turtles (Lepidochelys kempii) at Rancho Nuevo sanctuary, Tamaulipas, Mexico during 2018-2020. The sequential concentrations analyzed were Zn> Se> Cu> As> Pb; while Cd and Hg concentrations were below the limits of detection (0.01 µg g-1). No significant differences were observed between the concentrations of trace elements (p> 0.05) by year, except Se levels, possibly resulting from recorded seasonal differences in turtle size. No relationships among turtle size vs elements concentration were observed. In conclusion, essential and toxic trace elements concentrations in the blood of nesting Kemp's ridley turtles may be a reflex of the ecosystem in which the turtles develop, that is, with low bioavailability of elements observed in the trophic webs in the Gulf of Mexico.

Trace element concentrations in muscle tissue of milk shark, (Rhizoprionodon acutus) from the Persian Gulf.

We analyze the heavy metals concentrations in muscle samples of milk shark (Rhizoprionodon acutus) from Persian Gulf. The metals distribution was Zn > Cu > Pb > Cd > Hg. No statistical differences were observed among size or weight by sex (p < 0.05). Metals concentrations in the population de R. acutus from Larak and Lavan islands are homogeneous along the coastal study area. Our study suggest that the results reflect the natural contents of trace metals in this species, and the health risk associated to milk shark consumption in Persian Gulf is relatively low.

Mercury, lead, and cadmium in tissues of the Caspian Pond Turtle (Mauremys caspica) from the southern basin of Caspian Sea.

Concentrations of cadmium, lead, and mercury were measured in different tissues (liver, muscle, and shell) of 60 Caspian Pond Turtles collected from Tajan and Shiroud Rivers, southern basin of the Caspian Sea. Based on the results, different tissues showed different capacities for accumulating trace elements. The general trend of metals accumulation was: liver > shell > muscle. Results also showed that accumulation of these elements was not significantly different between sex and river in turtles (p > 0.05). Based on the results, Hg and Pb concentrations recorded in the present study were higher than some of the maximum concentration permissible. To our knowledge, this is the first report into heavy metal accumulation in tissues and organs of Caspian Pond Turtle from the southern basin of Caspian Sea. Further studies are needed to measure different heavy metals and trace metals in this valuable species.