Barnacles are common, rough, shelled growths found on many marine animals, including sea turtles. While often considered a natural part of a turtle’s life, their impact can range from harmless to a significant health concern. This article explores the connection between barnacles and sea turtle health.
Understanding Turtle Barnacles
Barnacles are crustaceans, related to crabs and shrimp, that adapt to a sessile lifestyle as adults, meaning they remain fixed in one place. They attach to hard underwater surfaces like rocks, ship hulls, and the shells or skin of marine animals such as sea turtles. Most barnacles on sea turtles belong to the genus Chelonibia.
Barnacle larvae, called cyprids, are mobile and seek a suitable surface to settle. Once a cyprid finds a spot, it secretes a powerful, glue-like substance to permanently cement itself to the turtle’s shell or skin. This adhesive is remarkably strong. As filter feeders, adult barnacles extend feathery appendages, called cirri, into the water to capture plankton and other microscopic food. The continuous movement of the turtle provides barnacles with a steady flow of water, ensuring a constant food supply. This relationship is often described as commensalism, where the barnacle benefits by gaining a place to live and feed, while the turtle is generally unaffected.
How Barnacles Impact Turtle Health
While many barnacles do not directly harm sea turtles, their presence can negatively affect a turtle’s well-being. One significant impact is increased drag. A heavy covering of barnacles increases the turtle’s surface area, creating more resistance as it moves through water. This forces the turtle to expend more energy for swimming, foraging, and migrating.
Barnacles can also cause physical irritation, especially if they attach near sensitive areas. Some species, known as embedding barnacles, can burrow into the turtle’s skin or shell, causing irritation and creating open wounds. These attachment sites can become susceptible to bacterial and fungal infections. Barnacles attached around the eyes or nostrils can obstruct vision or breathing, hindering the turtle’s ability to find food or surface for air. These impacts are typically minor in healthy turtles, which are generally able to cope with a normal barnacle load.
When Barnacle Infestations Become Critical
Barnacle infestations can escalate to a life-threatening level. Extreme overgrowth, also known as heavy biofouling, significantly increases drag and weight, making it difficult for the turtle to swim efficiently. This reduced mobility can impair the turtle’s ability to forage, escape predators, or dive effectively, leading to exhaustion and starvation. A heavy barnacle load can also negatively impact a turtle’s buoyancy, making it harder to surface for air, which can result in drowning in severe cases.
Barnacles attached to critical areas, such as the mouth, nostrils, or eyes, can severely impede feeding, breathing, or sight. For example, barnacles growing over the eyes can obstruct vision, making it hard for the turtle to locate food and avoid dangers. Weakened or injured turtles are more susceptible to severe infestations because they may not be able to naturally dislodge barnacles or cope with the added burden. A high volume of barnacles often indicates that the turtle is already compromised due to illness, injury, or malnutrition. In these critical situations, the cumulative effects of increased energy expenditure, impaired senses, and susceptibility to infection can lead to starvation, drowning, or increased vulnerability to predators, ultimately resulting in mortality.
What Happens to Turtles with Severe Barnacles
Turtles facing severe barnacle infestations employ natural coping mechanisms. Healthy turtles can often keep barnacle growth in check through regular activity and by rubbing against rocks or abrasive surfaces to dislodge them. Additionally, sea turtles naturally shed their scutes, the plate-like scales on their shell, as they grow. This shedding process helps to remove attached barnacles and other epibionts.
When natural methods are insufficient, human intervention becomes necessary for severely impacted individuals found stranded or in distress. Marine animal rescue and rehabilitation centers provide care for these turtles. Veterinary professionals carefully remove barnacles, often using specialized tools, to alleviate suffering and improve the turtle’s chances of survival. This removal must be done cautiously to avoid further injury or infection to the turtle’s shell or skin. After barnacle removal, turtles typically receive medical treatment for any wounds or infections and are observed for a period before being released back into their natural habitat.