Highlighting & eradicating an UNACKNOWLEDGED source of plastic waste into our ocean
Hawksbill Turtle
The Critically Endangered Coral Reef Custodian : Key Stage 2 CARD05
Eretmochelys imbricata - The hawksbill sea turtle is a striking and critically endangered species of sea turtle, instantly recognizable by its beautiful, patterned shell and its unique head shape.
Average Life Span: 50 to 60 years (Approx.)
Size: 25 to 39 inches (65 to 100 cm)
Weight: 100 to 150 lbs (45 to 68 kg)
Diet: Hawksbills have a highly specialized diet, primarily consisting of sea sponges (often making up 70-95% of their diet in some regions). They use their sharp, narrow beaks to scrape sponges off coral reefs. Many of the sponges they consume are toxic to other marine animals due to the presence of glass-like spicules or harmful chemicals. Hawksbills possess a remarkable immunity to these toxins, allowing them to exploit a food source that few other creatures can utilize. By consuming sponges, hawksbills play a crucial role in maintaining the health and biodiversity of coral reefs. Sponges compete with corals for space and light; by keeping sponge populations in check, hawksbills prevent them from overgrowing and suffocating corals, thereby promoting coral growth and overall reef ecosystem health. They may also consume other invertebrates and algae.
Reproduction and Life Cycle: Female hawksbills exhibit strong fidelity to their natal beaches, returning to the very same sandy shores where they hatched decades earlier to lay their own eggs. Unlike species that nest in large aggregations, hawksbills typically nest individually or in low densities on scattered, secluded beaches, often seeking cover under coastal vegetation. They are slow to mature, reaching sexual maturity between 20-30 years of age. Their exact lifespan is not definitively known but is believed to be long, possibly 30-50 years or even more.
Conservation Status (Critically Endangered)
- "Tortoiseshell" Trade: The most significant historical and ongoing threat to hawksbill turtles is the demand for their beautiful shells. Their scutes were highly valued for making "tortoiseshell" products such as jewelry, combs, eyeglasses, and decorative items. Despite international trade bans (under CITES Appendix I), illegal trafficking still persists in some regions, continuing to decimate populations.
- Bycatch: Accidental capture in commercial fishing gear (gillnets, trawls, longlines) remains a major threat, leading to injury or drowning.
- Habitat Loss and Degradation: Coastal development, pollution (including plastic waste), and climate change (leading to coral bleaching and ocean acidification) directly impact their critical coral reef foraging habitats and nesting beaches.
- Egg Harvesting: In some areas, the collection of eggs for consumption or sale continues to be a problem.
- Climate Change: Rising sea levels can inundate nesting beaches, and increased sand temperatures can skew sex ratios towards females, further impacting population viability.
The hawksbill turtle's unique biology and vital role in maintaining the health of coral reef ecosystems underscore the urgency of robust conservation efforts to protect them from extinction.
Worldwide Distribution
Hawksbill Turtles Across The World
Hawksbills are strongly associated with tropical and subtropical coral reefs worldwide. They are typically found in shallow coastal waters, rocky areas, lagoons, and mangrove swamps, where their sponge prey is abundant. They are found in the Atlantic, Pacific and Indian Oceans, within tropical and some subtropical regions. While some other sea turtle species may migrate in large groups hawksbills are generally solitary foragers often having individual "home reefs" where they spend significant portions of their adult lives.
How Ocean Plastic Waste affects Hawksbill Turtles
Hawksbill turtles are critically endangered, and ocean plastic waste poses a significant and multifaceted threat to their survival. As a species intimately linked to coral reefs and coastal habitats, they are particularly vulnerable to both the physical dangers and the insidious chemical impacts of plastic pollution.
Here's how plastic waste affects hawksbill turtles:
Ingestion of Plastic Debris
- Mistaking Plastic for Food: Hawksbill turtles have a unique diet, primarily consisting of sea sponges found on coral reefs. However, they are also known to eat other invertebrates and algae. Unfortunately, floating plastic bags and other debris can often resemble jellyfish, algae, or other food items that sea turtles, including hawksbills, might consume.
- Accidental Ingestion: Even when targeting their preferred prey, hawksbills can inadvertently ingest smaller plastic pieces that are present in their foraging grounds.
- Microplastic Ingestion: This is an increasingly recognized and widespread problem. Microplastics (plastic particles smaller than 5mm) are pervasive in marine environments. Hawksbills can ingest these tiny particles directly or, more commonly, indirectly through their prey. Studies on sea turtles, including some on hawksbills, have found microplastics in their digestive tracts and even other organs.
Health Consequences of Ingestion:
- Internal Blockages: Ingesting larger pieces of plastic can cause severe blockages in their digestive system, preventing them from absorbing nutrients or passing waste, leading to starvation and death.
- Internal Injuries: Sharp or rigid plastic fragments can cause lacerations, perforations, and internal bleeding.
- False Satiation: Plastic filling their stomachs can create a false sense of fullness, reducing their appetite for actual food and leading to malnutrition and weakness.
- Buoyancy Problems: Ingested plastic can cause unnatural buoyancy, making it difficult for them to dive for food, rest on the seabed, or escape predators.
- Chemical Leaching: Plastics contain and absorb toxic chemicals (like PCBs, phthalates, and BPA). When ingested, these chemicals can leach into the turtle's body, accumulating in their tissues. These toxins can lead to:
- Immune system suppression: Making them more susceptible to diseases.
- Reproductive issues: Affecting fertility, egg quality, and hatchling viability, which is devastating for an already endangered species.
- Endocrine disruption: Interfering with their hormonal systems, impacting growth and development.
- Organ damage.
Entanglement in Plastic Debris
- "Ghost Fishing Gear": Hawksbill turtles are highly susceptible to entanglement in abandoned, lost, or discarded fishing gear (nets, lines, traps), often referred to as "ghost gear." This is a massive problem in coastal waters where they forage.
- Other Plastic Debris: Other large plastic items like plastic sheeting, strapping bands, or even six-pack rings can also cause entanglement.
- Consequences of Entanglement:
- Physical Injury: Entanglement can cause severe cuts, abrasions, and deep wounds that can lead to infection, necrosis, and even the amputation of limbs.
- Impaired Movement: Being tangled restricts their ability to swim, forage for food, or escape predators.
- Drowning: As air-breathing reptiles, turtles must surface to breathe. If entangled underwater, or if the plastic debris drags them down, they can drown.
- Starvation: Inability to forage due to entanglement can lead to slow, agonizing starvation.
- Growth Restriction: If young turtles become entangled, the plastic can constrict their growth, deforming their shells and bodies over time.
Impact on Nesting Beaches and Hatchlings
- Obstruction on Beaches: Plastic debris accumulating on nesting beaches can create physical barriers that prevent adult female hawksbills from reaching suitable nesting sites or obstruct hatchlings from successfully making their perilous journey from the nest to the sea.
- Microplastics in Sand: Studies are exploring how microplastics in beach sand might affect nest temperatures (which determine the sex of the hatchlings) and the permeability of the sand, potentially impacting nest productivity and hatchling development.
Given their critically endangered status and their close association with coastal and reef environments, hawksbill turtles are at an exceptionally high risk from the pervasive and persistent threat of ocean plastic pollution.