United States - September 07, 2025 Sea turtle hatchlings face a new danger on Florida beaches as massive mats of sargassum seaweed block their path to the ocean. This annual journey, critical for survival, has become more perilous due to record sargassum accumulation. Researchers from Florida Atlantic University studied leatherbacks, loggerheads, and green turtles on beaches in Juno Beach, Jupiter, and Boca Raton. Using controlled crawlways with sargassum up to 19 centimeters high, they measured how the seaweed slowed the hatchlings and increased their risk. The study found that leatherbacks took 54% longer to cross light sargassum and 158% longer through heavy mats. Loggerheads were slowed by 91% in light sargassum and 175% in heavy coverage. Green turtles experienced delays of 75% and 159%, respectively. Hatchlings frequently flipped over while climbing the seaweed, sometimes more than 20 times, increasing their exposure to predators and heat. “The longer a hatchling stays on the beach, the more at risk it becomes – not just from predators like birds and crabs, but also from overheating and dehydration,” said Sarah Milton, Ph.D., senior author and professor at FAU. “When sargassum piles are higher – some over a meter – we can expect more failed attempts, particularly when hatchlings face multiple bands of seaweed.” Despite these delays, blood glucose levels remained stable, suggesting hatchlings retain energy even while navigating dense sargassum. Researchers warn that ongoing growth of sargassum could block hatchlings entirely, threaten nesting areas, and reduce long-term survival. The study highlights the urgent need for responsive beach management to protect these vulnerable species.