Master's Thesis Defense - Lyndsey Tanabe

Nov 14 2018 11:00 AM - Nov 14 2018 12:00 PM

Tanabe.JPG TITLE: Sand temperature profiles at turtle nesting sites in the Red Sea: implications on   hatchling sex ratios

 ADVISOR:  Prof. Michael Berumen

 DATE:  Wednesday, November 14, 2018

 TIME:  11:00 a.m. - 12:00 noon

 LOCATION: Building 4 (seaside) · Level 5 · Room 5220

ABSTRACT: Climate change poses a serious threat to species that demonstrate temperature-dependent sex determination (TDS), including marine turtles. Increased temperatures can result in highly female skewed sex ratios and decreased hatchling success, potentially leading to localized population extinctions.  In situ sand temperature data were collected from the nesting depth of hawksbill and green turtles at five study sites along the coast of the Red Sea. The sand temperature profile at four of the sites exceeded the pivotal temperature (29.2℃), which suggests feminization of turtles at these sites. Sand temperature recordings were as high as 35.97℃ at 30 cm depth, and 35.34℃ at 50 cm.  These temperatures exceed the maximum thermal threshold of between 33 and 35℃ often cited in literature.  Thus, the turtle hatchlings in some areas of the Red Sea could already have high mortality rates due to high temperatures. The Red Sea is home to five out of the seven extant species of marine turtles in the world, yet not much is known about these populations. The Red Sea is an understudied region of the world, yet it has the potential to provide insight on how species might adapt to future climate change due to its high and variable water temperatures (20°C to 35°C) and high salinity (40 PSU).  Identifying which sites have lower sand temperatures could help identify nesting sites that are less likely to experience feminization, representing priority areas for conservation efforts and critical habitats to avoid coastal development.