Sargassum seaweed, a floating brown algae that is often found washed up on shorelines from Florida down to South America, are creating a barrier for hatchling sea turtles trying to get to the sea.
Sargassum seaweed, a floating brown algae that is often found washed up on shorelines from Florida down to South America, are creating a barrier for hatchling sea turtles trying to get to the sea. This is according to a Florida Atlantic University study published by the Coastal Research Online Journal. These natural barriers make it more difficult for the hatchlings to make it to the ocean and also make them more vulnerable to predators, the study noted.
The study looked at the physiological response and physical performance of the loggerhead sea turtle (Caretta caretta), leatherback turtle (Dermochelys coriacea) and the green sea turtle (Chelonia mydas) as they traversed pathways with and without sargassum. The turtles were on both Juno, Jupiter, and Boca Raton in Florida. What the researchers found was the addition of sargassum stacked 7.5 inches high increased the time it took for the hatchlings to crawl the length of a 15m controlled pathway versus a 15m controlled pathway with no Sargassum present. These pathways simulated a natural pathway the turtles would take down to the water’s edge and into the ocean.
Young Loggerhead Sea Turtles Spend Lost Years Floating In Seaweed
The researchers then conducted blood glucose level testing and righting response times (the time it takes for the turtle to flip itself upright in water) and found no discernible difference in the righting response times, but a significantly lengthier time navigating through the algae and into the water. this, the researchers say, leaves the hatchlings vulnerable to predation for longer periods of time. Some hatchlings in the study were unable to complete the climb within the time allowed.
Based on median values, the researchers noted that leatherback turtles took 54 percent longer to crawl through the light sargassum and 158 percent longer through the heavy sargassum. Loggerhead turtles took 91 percent longer to crawl through the light sargassum and 175 percent longer in the heavy sargassum. Green turtles were delayed by 75 percent and 159 percent respectively.
Another element of the study was the flipping of the turtles as they tried to climb up and over the sargassum. This proved to be a hindrance to their march toward the open ocean, with one hatchling flipping over more than 20 times. This increases their risk of predation as well as heat exposure.
“For sea turtle hatchlings, reaching the ocean is already a race against time – and survival. Now, increasingly large mats of sargassum are adding new challenges to this critical journey,” Sarah Milton, Ph.D., senior author and chair and professor, FAU Department of Biological Sciences. said in a statement put out by the university. “As these seaweed accumulations grow taller and more widespread, they risk blocking hatchlings entirely, draining their limited energy or leaving them stranded. Beyond impeding movement, sargassum may also reduce nesting space and alter incubation conditions.”
An abstract of the paper, “Physiological Effects of Sargassum Beach Coverage on Three Species of Sea Turtle Hatchlings” can be read on the Journal of Coastal Research Online Journal.
