When observing sea turtles, it is common to notice various organisms attached to their shells and skin. Among these, barnacles are frequently seen, appearing as hard, white or grey growths. These attachments are a natural part of the marine environment and often spark questions about their nature and potential effects on the turtles.
Understanding Turtle Barnacles
Barnacles are a type of crustacean, related to crabs and lobsters, with a sessile lifestyle as adults. They are filter feeders, straining small organisms from the water. While many barnacle species attach to rocks or submerged structures, “turtle barnacles” are specialized varieties adapted to live on sea turtles. They are commonly found on these marine reptiles.
Unlike typical rock barnacles that form conical shells, some turtle barnacles can appear flatter or more integrated with the turtle’s surface. They develop from mobile larvae, called cyprids, which settle on a suitable substrate like a turtle. Once settled, they secrete a powerful, glue-like substance to secure themselves permanently. This adaptation allows them to benefit from the constant water flow and nutrient availability that a moving host provides.
Their Unique Attachment to Turtles
Barnacles adhere to turtle shells using a strong adhesive. This attachment provides a stable surface and access to feeding currents as the turtle moves. The relationship is commensal: the barnacle benefits by gaining a mobile platform for feeding and dispersal, while the turtle is unaffected.
Sea turtles serve as suitable hosts due to their relatively slow swimming speeds and the large, hard surface area of their shells. This provides an ideal environment for barnacle larvae to settle and mature, ensuring a continuous supply of plankton for the adult barnacles to filter feed.
Impact on Turtle Health and Movement
While often harmless, barnacles can impact sea turtles. A significant number of barnacles can increase the turtle’s hydrodynamic drag, requiring more energy for swimming. This increased effort could affect foraging efficiency or migration success, especially for turtles already in poor health.
Barnacles can also cause direct issues. Certain species can embed themselves into the turtle’s shell or soft tissue, causing irritation or small lesions. If barnacles attach near sensitive areas like the eyes or mouth, they can obstruct vision or feeding. However, severe harm from barnacle infestations is rare, and healthy turtles cope well with their presence.
Natural and Human Intervention
Sea turtles have natural mechanisms to manage barnacle growth. As turtles grow, they periodically shed the outer layers of their scutes, which can dislodge some attached barnacles. Turtles have also been observed rubbing against rocks or other objects to scrape off barnacles.
Human intervention to remove barnacles from wild turtles is not advised unless the turtle exhibits signs of distress or health compromise. For turtles found in rehabilitation centers due to injury or illness, veterinary staff may carefully remove barnacles. This selective removal aims to alleviate burdens without causing additional stress or injury to the animal.