Turtles

By comparing shell lengths, researchers from the University of Central Florida (UCF) have discovered that loggerhead and green sea turtles have become smaller in size over the past few decades.

They have yet to come up with an explanation for this, according to a study published in the Ecosphere journal.

Thanks for advancements in tracking technologies, scientists have discovered an intriguing behavioural trait amongst some marine species: They sometimes swim in circles.

When studying the navigational abilities of sea turtles, Tomoko Narazaki, a marine researcher at the University of Tokyo, observed that the turtles in her study would swim in circles so constantly “just like a machine.”

In the future, sea turtles in the US will find it harder to find suitable nesting habitat, due to climate change, rising sea levels and coastal development.

A team led by Florida State University came to this conclusion after their research which modelled the suitability of coastal habitats in the eastern United States by 2050 for sea turtle nesting, after considering predicted sea-level rise and future climates.

Their findings were recently published in the Regional Environmental Change journal.

Despite good swimming abilities, juvenile loggerhead turtles are thought to drift passively for a significant portion of their existence on the high seas

However, a study by researchers from National Oceanic and Atmospheric Administration has found that turtles were swimming against the prevailing current in a statistically significant pattern at a rate of 30 cm/sec, which indicates an ability to detect the current flow and orient themselves to swim into the current flow direction.

This study provides (...) compelling evidence that these turtles are able to resist such transport using some mechanism not yet fully understood.

—Dr. Donald Kobayashi, National Oceanic and Atmospheric Administration

To understand sea turtle behavior around ocean plastics, the research team compared how sea turtles in a lab setting reacted to smelling odors of turtle food, ocean-soaked plastic, clean plastic and water.

The turtles ignored the scents of clean plastic and water, but responded to the odors of food and ocean-soaked plastics by showing foraging behavior. This included poking their noses out of the water repeatedly as they tried to smell the food source, and increasing their activity as they searched.

A team of researchers from the University of Michigan focused on leatherback sea turtles nesting on St. Kitts, an island in the West Indies southeast of Puerto Rico. The team wanted to know what factors influence where and when the leatherbacks lay their eggs.

It has been suggested that characteristics of the sand, the slope of the beach and proximity to vegetation contribute to the success or failure of nests, but which factors cause female leatherback sea turtles to dig a nest in a particular spot has never been investigated.

The central African country of Gabon is providing an invaluable nesting ground for a vulnerable species of sea turtle. During a survey of nearly 600 km of Gabon's coastline, scientists from the University of Exeter uncovered the Atlantic’s largest breeding colony of olive ridley turtles. Study results estimate that there could be up to 9,800 turtle nests per year, compared with around 3,300 in French Guiana and 3,000 in Brazil.

Already at risk from oil spills, hunting and habitat destruction, sea turtles have another obstacle to contend with: decompression sickness, also known as the bends. Scientists claim the sickness has been diagnosed for the first time in loggerhead sea turtles, with individuals accidentally caught in fishing nets most likely to suffer.