Plastic pollution threatens marine ecosystems globally and impacts marine life, with particular attention drawn to sharks. Understanding how plastic harms these animals is important for ocean health.
How Plastic Harms Sharks
Sharks are harmed by plastic through entanglement and ingestion. Entanglement occurs when sharks become ensnared in larger plastic debris, particularly abandoned, lost, or discarded fishing gear, often called “ghost nets.” Plastic strapping bands can also constrict a shark’s body, leading to severe injuries, restricted movement, and an inability to hunt or breathe effectively. This can result in suffocation, starvation, or infected wounds.
Ingestion is another threat, as sharks may mistake plastic pieces for prey. Filter-feeding sharks, like whale sharks and basking sharks, are vulnerable to consuming microplastics directly from the water. Other species, such as tiger and hammerhead sharks, also ingest these particles. Ingested plastics can cause internal injuries, blockages, or a false sense of fullness, leading to malnutrition and starvation. Plastics can also leach harmful chemical toxins into the shark’s body.
Estimating the Toll: How Many Sharks Die?
Quantifying the exact number of sharks that die from plastic each year is challenging due to the ocean’s vastness and difficulty in observing and documenting such events. Many deaths go unobserved. Estimates highlight the scale of the problem for marine animals as a whole. Over 1 million marine animals, including fish, mammals, and seabirds, die annually from plastic pollution. About 100,000 marine animals die each year specifically from entanglement in plastic debris.
Studies indicate hundreds of sharks are reported to die from entanglement. For example, research on tiger sharks revealed 3% of sampled individuals suffered severe trauma from circular plastic straps. Documented cases include whale sharks that died due to ingested plastic, such as a hardened straw perforating an esophagus or intestinal damage from plastic pieces. These cases confirm plastic pollution directly causes shark mortality, even if the full extent remains unquantified.
Beyond Mortality: Broader Effects and Data Gaps
Beyond mortality, plastic pollution causes sublethal effects on sharks, impacting their health and ecological roles. Sharks can experience chronic stress, reduced reproductive success, and impaired immune function due to plastic exposure. Chemical additives and pollutants associated with plastics can disrupt hormonal balance, influencing growth, metabolism, and reproductive processes. As long-lived apex predators, sharks are susceptible to accumulating plastics and toxins in their tissues over time.
Plastic pollution also indirectly affects shark populations by degrading their habitats and food sources. Plastic can alter marine environments, potentially forcing sharks to search for food elsewhere and increasing their exposure to plastic particles. The full scope of these broader effects is difficult to quantify due to monitoring challenges. These data gaps suggest the problem’s true magnitude is greater than currently understood, impacting the long-term viability of shark populations.
Tackling the Problem: Solutions and Prevention
Addressing plastic pollution requires a multi-faceted approach, starting with individual actions. Reducing single-use plastics like bags, bottles, straws, and packaging is effective. Opting for reusable alternatives such as coffee cups, water bottles, and shopping bags reduces one’s plastic footprint. Proper recycling also prevents plastics from entering the environment.
Broader efforts include improving global waste management systems to ensure plastic is collected and processed effectively, and participating in beach and ocean clean-up initiatives. On a larger scale, governmental policies and regulations are needed to reduce plastic production, ban problematic single-use plastics, and promote sustainable alternatives. Supporting legislation that holds industries accountable for their plastic waste can drive systemic change. Raising public awareness and educating communities about plastic pollution are also important for collective action and long-term solutions.