Sea turtle eggs are heavily infuenced by the environment in which they incubate, including efects on hatching success and hatchling viability (hatchling production). It is crucial to understand how the hatchling production of sea turtles is infuenced by local climate and how potential changes in climate may impact future hatchling production. Generalized Additive Models were used to determine the relationship of six climatic variables at diferent temporal scales on loggerhead turtle (Caretta caretta) hatchling production at seventeen nesting beaches in Bahia, Espirito Santo, and Rio de Janeiro, Brazil. Using extreme and conservative climate change scenarios throughout the 21st century, potential impacts on future hatching success (the number of hatched eggs in a nest) were predicted using the climatic variable(s) that best described hatchling production at each nesting beach. Air temperature and precipitation were found to be the main drivers of hatchling production throughout Brazil. CMIP5 climate projections are for a warming of air temperature at all sites throughout the 21st century, while projections for precipitation vary regionally. The more tropical nesting beaches in Brazil, such as those in Bahia, are projected to experience declines in hatchling production, while the more temperate nesting beaches, such as those in Rio de Janeiro, are projected to experience increases in hatchling production by the end of the 21st century.

Full reference: Montero, N., P. S. Tomillo, V. S. Saba, M. A. G. dei Marcovaldi, M. López-Mendilaharsu, A. S. Santos, and M. M. P. B. Fuentes. 2019. Effects of local climate on loggerhead hatchling production in Brazil: Implications from climate change. Scientific Reports 9:8861.

Multi-species conservation strategies can be useful to maximize allocation of resources. To effectively plan for multi-species management practices, it is important to have a robust understanding of the variability in the spatial and behavioral ecology of sympatric species. To address this in the context of marine turtles, this study explored fine-scale habitat use by three sympatric species [juvenile green turtles (Chelonia mydas), Kemp’s ridley turtles (Lepidochelys kempii) and loggerhead turtles (Caretta caretta)] in a foraging area near Crystal River, Florida, United States. By combining sighting surveys and satellite tracking methods, we found that the distribution of the three species of marine turtles in this region overlapped both in space and time. We also observed differences in the fine-scale location of hotspots and in-water behavior among species, with some degree of apparent habitat partitioning. Habitat partitioning was particularly evident when assessing the diving and surfacing behavior of tracked turtles, with some degree of differentiation in diel diving patterns, particularly depths utilized during daytime/nighttime and the dive/surface duration. Our study provides ecological baseline data on the spatial overlap, habitat use and behavior of three sympatric marine turtle species, which can inform future management strategies at nearshore marine habitats in the Northeastern Gulf of Mexico.

Full reference: 
Wildermann, N.E., Sasso, C.R., Stokes, L.W., Snodgrass, D.,  Fuentes, M.M.P.B. (2019). Habitat use and behavior of multiple species of marine turtles at a foraging area in the Northeastern Gulf of Mexico. Frontiers in Marine Science. 6, 155. ​

The environment and climate in which sea turtle eggs incubate affects how successful and viable hatchlings are. Therefore, it is crucial to understand how local climate impacts sea turtle hatchling production as well as how potential changes in climate may impact future hatchling production. In this study, we investigated the effects of five climate variables at different temporal scales on loggerhead sea turtle (Caretta caretta) hatchling production from North Florida, USA. Humidity, air temperature, and accumulated precipitation were the main climatic drivers of hatchling production, while sea surface temperature and wind speed did not demonstrate to have strong effects. Climate projections show air temperatures increasing at the nesting beaches throughout the 21st century, while precipitation and humidity projections vary between sites and projection scenarios. Due to the temperate nature of these nesting beaches, increases in hatching success for nests that incubate undisturbed (not affected by depredation and storm-related impacts) are projected for this region by 2100. This study demonstrates how different climate variables and their interactions can have a determining effect on an important marine species.

Reference: Montero, N., Ceriani, S.A., Graham, K., Fuentes, M. M. P. B. (2018). Influences of the local climate on loggerhead hatchling production in North Florida: Implications from climate change. Frontiers in Marine Science, 5, 262​

Species’ foraging choices influence their somatic growth rates, age at maturity, and time spent in vulnerable early life stages. Thus, differences in population demographics are often attributed to variability either in diet type, quality, and/or quantity ingested. Knowledge of diet selection, though currently limited, can enhance our understanding of the roles of marine turtles in marine ecosystems and, at a finer scale, elucidate how nutrition and diet influence their growth and productivity. To investigate this relationship, we coupled stable isotope analysis with a diet preference index to provide insights into the selection and plasticity of juvenile green turtle Chelonia mydas diet. The study was conducted at 2 sites (Bonefish Hole and South Bimini) in Bimini, Bahamas, in 2016. Habitat surveys were conducted to gather habitat data and determine resource availability. A dichotomy in diet was found between the sites: at Bonefish Hole, turtles exhibited a more generalist omnivorous diet, selecting for sessile filter feeders and green algae, whereas turtles in South Bimini had a more specialist herbivorous diet, primarily consuming seagrasses and selecting for red algae, when available. The foraging dichotomy found in this study expands our understanding of the spatial differences in green turtle biology in the Bahamas and provides novel information for turtle foraging in Bimini. Knowledge about differences in intra-specific diet, with a focus on diet selection and potential drivers, can shed light on the factors that influence critical life history traits and ultimately inform species management.

​Gillis, A. J., Ceriani, S. A., Seminoff, J. A., Fuentes, M. M. P. B. (2018). Foraging ecology and diet selection of juvenile green turtles in the Bahamas: insights from stable isotope analysis and prey mapping. Marine Ecology Progress Series, 599, 225-

 This summer marks the 3rd field season for Ph.D. candidate Matt Ware at the Bon Secour National Wildlife Refuge in Fort Morgan, Alabama working alongside the U.S. Fish and Wildlife Service and Share the Beach, an all-volunteer sea turtle conservation group. It has been a quiet year so far – only 30 nests, when in the last 2 years there have been 94 and 86 nests, respectively. Hatching has started with hatchlings from the only Kemp’s ridley nest on the refuge emerging on Monday 16 July. During the excavation, 108 eggs were found with 87 hatchlings successfully reaching the water. The first loggerhead nest should be hatching any day now.

His research this time around focuses on 1) studying the inundation tolerance of developing sea turtle embryos, and 2) the effect of Leave No Trace ordinances on nesting success. In past years, Matt has investigated the changes in incubation conditions associated with nest relocation and mapping wave runup exposure to identify high-risk nesting locations. To better inform these management strategies and tools, more information is needed on how well developing sea turtle embryos “hold their breath”. How long can embryos remain underwater and still hatch successfully? How does this tolerance vary with the timing of inundation relative to embryonic development and the frequency of inundation? Matt is using HOBO U20L-04 water level loggers to answer these questions, including 2 loggers donated by Onset Computer Corporation. Tropical Storm Alberto arrived in the northern Gulf of Mexico very early in the nesting season, so only 2 nests were affected. The peak of hurricane season is still to come in August and September – and the loggers are ready and waiting. This project has been funded by a Section 6 grant from the Alabama Department of Conservation and Natural Resources.

The second component of his research this summer constitutes the final year of data collection on a multi-year project tracking the nesting success across Baldwin County, Alabama. In 2015, the cities of Gulf Shores and Orange Beach enacted Leave No Trace ordinances. The “Leave Only Footprints” program as it is called forces beachgoers to remove their equipment from the beach no later than 1 hour after sunset or face civil penalties. This program does not apply to unincorporated Fort Morgan, and the 2 local protected areas – the Bon Secour NWR and Gulf State Park – already have their own versions of the Leave No Trace ordinance. By comparing nesting data before and after the enactment of the “Leave Only Footprints” program and within each year across the county, Matt will be able to assess if the program has improved nesting success, or at least decreased the frequency of obstructed crawls, in Gulf Shores and Orange Beach.
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Unfortunately, on Saturday 14 July, the need for such ordinances was demonstrated when a mature female Kemp’s ridley was found washed up during morning nesting patrol on the Bon Secour NWR apparently strangled by a beach chair. Matt assisted the Alabama Sea Turtle Stranding and Salvage Network in documenting the event and collecting the animal for later necropsy at the NOAA facility in Pascagoula, Mississippi. Images he captured of the turtle quickly went viral on social media and various news outlets. Posts on Matt’s personal Facebook page and the pages of Fort Morgan Share the Beach and the Bon Secour NWR have been viewed over 600,000 times and shared almost 9,000 times with almost 5,000 reactions. Now this’ story on the incident has been viewed 1 million times and shared over 12,000 times. The story was covered in the:

• NBC15, USA
• New York Times, USA
• Daily Mail, UK 
• Global News, Canada
• Huffington Post, South Africa
• Australia

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 Share the Beach has reached out to the Baldwin and Mobile County commissioners along with the governor of Alabama to urge them to support an expansion of the “Leave Only Footprints” program beyond the city limits. They, and Matt, hope that the images, though graphic, will encourage beachgoers to remove equipment from the beach at the end of the day, discard of damaged equipment properly, and help combat marine debris to prevent future impacts to wildlife.

When not in the field, Matt has been working on several manuscripts detailing his previous research in Alabama. Be on the look-out for his nest relocation manuscript currently in press in Chelonian Conservation and Biology and future manuscript on wave runup mapping.

Check out our new paper on the impacts of recreational scallop fisheries on marine turtles:

The impact of fisheries on marine megafauna is widely known but most studies have focused on commercial fisheries, overlooking the effect of local recreational fisheries. This is particularly important for marine turtles in near-shore habitats that overlap with recreational fisheries. We assessed the effect of recreational scallop fisheries on the distribution and behaviour of foraging marine turtles in the coastal waters of the upper Eastern Gulf of Mexico. Before and during the scallop season we quantified the density and overlap of marine turtles and vessels sighted, and satellite tracked four turtles to assess their distribution and behaviour. The relative distribution of marine turtles sighted during the scallop season overlapped with 48% of the area most frequently used by harvesters, and marine turtle activity hotspots shifted between seasons. In addition, during the scallop season the home range size of individual turtles appeared to decrease, and turtles displayed frequent changes in travel speed and directionality. We hypothesize that such changes are probably related to the distribution and movement of vessels and the abundant presence of people in the water. Our study highlights the importance of considering recreational fisheries and their local effect on marine megafauna for informing future adaptive management practices. However, further studies are needed to quantify the direct and indirect impacts of recreational fisheries and to assess the degree of risk of associated activities to marine turtle populations.

Reference:
Wildermann, N. Sasso, C., Gredzens, C., Fuentes, M. M. P. B. (2018). Assessing the effect of recreational scallop harvest on the distribution and behavior of foraging  marine turtles. Oryx

We were recently awarded three grants from the Sea Turtle Grants Program (see below). The Sea Turtle Grants Program is funded from proceeds from the sale of the Florida Sea Turtle License Plate. Learn more at www.helpingseaturtles.org


Fuentes, Mariana (PI), & Ingels, Jeroen Omer Georgette (Co-PI). (May 2018–May 2019). Life on Loggerheads: an integrated epibiosis study to assess foraging behavior, reproductive success and habitats of Northern Gulf of Mexico loggerheads nesting at St. George Island. Total award $10,571.
 
Fuentes, Mariana (PI), & Montero, Natalie Alexandra (Co-PI). (May 2018–May 2019). Assessing different sea turtle nest protection measures against coyotes.  Total award $12,413.
 
 Fuentes, Mariana (PI), & Wildermann, Natalie Elizabeth (Co-PI). (May 2018–May 2019). Integrative assessment of a loggerhead foraging aggregation in Crystal River. Total award $12,826.
 

Check out our new manuscript on microplastic at sea turtle nesting grounds:

Microplastics can impact key habitats used by endangered species, such as marine turtles. They impact the environment by transporting toxicants and altering sediment properties affecting temperature and sedimentpermeability. Our study determined the exposure of the ten most important nesting sites for the Northern Gulf of Mexico Loggerhead Recovery Unit to microplastic. Sand samples were obtained at each nesting site during the 2017 nesting season and analyzed for abundance and characteristics of microplastic. Microplastic was found at all sites, with an average abundance of 61.08 ± 34.61 pieces/m2, and 59.9% located at the dunes, where turtles primarily nest. A gradual decrease in microplastics abundance was observed from the most western nesting ground to the east. The results from this study indicate that microplastic accumulation on nesting sites for the Northern Gulf of Mexico may be of great concern, and could negatively affect the incubating environment formarine turtles.

Reference:
Beckwith, V. K. and Fuentes M. M. P. B. (2018). Microplastic at nesting   grounds used by the northern Gulf of Mexico loggerhead recovery unit. Marine Pollution Bulletin, 131, 32-37