Sharks And Plastic Pollution: Understanding The Impact

Sharks are apex predators, and their health is critical to maintaining the balance of marine ecosystems. However, they are under significant threat from plastic pollution. With an estimated eight million tons of plastic entering the oceans annually, sharks are increasingly exposed to plastic waste. They can become entangled in plastic debris, causing injury or death, and they also ingest microplastics, which can lead to health issues and even starvation. A study by the University of Exeter found that 67% of analysed sharks contained microplastics in their digestive systems. While the full impact of plastic pollution on sharks is yet to be determined, it is clear that urgent action is needed to address this growing environmental crisis.

Sharks ingest microplastics, which can cause severe injuries to their stomachs and intestinal mucosa

Sharks are at the top of the marine food chain, making them extremely vulnerable to plastic pollution. As apex predators, their diet consists of prey that consume other species at lower trophic levels. This makes sharks more susceptible to bioaccumulation. If a fish towards the bottom of the food chain consumes plastic, there is a significant chance that a shark consuming it will absorb those contaminants.

In the region of Java, whale sharks ingest about 137 pieces of plastic during one hour of feeding. The ingested plastic remains in the shark's stomach for an extended period and can cause mechanical damage to the stomach and intestinal linings through abrasion. It can also clog the digestive system, leading to starvation.

The impact of microplastics on shark health is not fully understood, but it is a growing concern. A study from the University of Exeter found that 67% of 46 analysed sharks contained microplastics in their digestive systems. The study highlights the pervasive nature of plastic pollution and its impact on marine life.

While entanglement in plastic debris and ingestion of larger plastic items can also harm sharks, the insidious nature of microplastics and their ability to cause internal injuries makes them a significant threat to shark populations.

Nanoplastics are dangerous as they can enter the bloodstream and accumulate in organs and cells

Nanoplastics can enter the human body through ingestion, inhalation, and skin contact. They can cross the gut-lung-skin barrier, which refers to the epithelial lining of the intestine, lung, and cutaneous layer. Nanoplastics have been found in the blood and other organs, including the spleen, lung, kidneys, liver, small intestine, heart, and brain.

Nanoplastics can cause harm to blood components, including plasma proteins, hematopoietic stem cells, red blood cells, white blood cells, platelets, and vascular endothelial cells. They can also cause systemic inflammation by triggering the release of immune system chemicals such as prostaglandins and cytokines.

The toxic effects of nanoplastics on blood components include:

• Plasma protein denaturation: Nanoplastics can change the secondary structure of plasma proteins, such as albumin and fibrinogen, which are essential for maintaining the osmotic balance of blood and carrying nutrients and drugs. This can lead to nutrient and oxygen deficiency.
• Hematopoietic stem cell dysfunction: Nanoplastics can suppress the proliferation and differentiation of hematopoietic stem cells, leading to disorders of the hematopoietic system.
• Red blood cell abnormalities: Nanoplastics can cause hemolysis, oxidative stress, and structural changes in red blood cells, which can result in anemia, polycythemia, and cardiovascular diseases.
• White blood cell dysfunction: Nanoplastics can cause cytotoxicity, oxidative stress, and a decrease in white blood cell count, which can compromise the effectiveness of the immune system.
• Platelet abnormalities: Nanoplastics can affect the coagulation cascade and cause platelet aggregation, leading to coagulation disorders and bleeding.
• Vascular endothelial cell damage: Nanoplastics can impair vascular endothelial function, leading to cardiovascular disorders such as atherosclerosis and hypertension.
• Altered biochemical parameters: Nanoplastics can alter hemato-biochemical parameters, such as bilirubin, blood urea nitrogen, uric acid, creatinine, and liver enzymes, which can be indicators of autoimmune diseases and inflammation.

Plastic pollution can alter the hormones that regulate growth, development, metabolism and reproductive functions

Plastic pollution is a pressing issue that affects marine life, including sharks. Sharks and other sea creatures can get entangled in plastic waste, which can cause them to suffocate, become unable to eat, or become easy prey. In addition, sharks can ingest plastic, which can remain in their stomachs for long periods, causing severe injuries to their stomach and intestinal mucosa and blocking their digestive system, leading to starvation.

One of the most concerning aspects of plastic pollution is the presence of microplastics and nanoplastics, which are tiny plastic particles that can penetrate the organs and cells of marine animals. Research has shown that 67% of sharks analyzed contained microplastics and other man-made fibers in their digestive systems. These microplastics can be ingested by sharks directly or through their food sources, such as crustaceans.

The impact of microplastics on shark health is still being studied, but it is known that microplastics can alter the hormones that regulate growth, development, metabolism, and reproductive functions in various organisms, including sharks. Microplastics have been found to affect the hypothalamic-pituitary-thyroid/adrenal/testicular/ovarian axis, leading to oxidative stress, reproductive toxicity, neurotoxicity, cytotoxicity, developmental abnormalities, decreased sperm quality, and immunotoxicity.

The endocrine system is responsible for regulating hormones that control various bodily functions, including growth, development, metabolism, and reproduction. Endocrine-disrupting chemicals (EDCs) found in plastics can interfere with the normal functioning of the endocrine system, leading to adverse health effects. These chemicals can act as agonists or antagonists for hormone receptors, disrupting the delicate balance of the endocrine system.

In sharks, the impact of plastic pollution on their hormones and health is still being studied, but it is clear that plastic pollution is a significant threat to their well-being and survival. The pervasive nature of plastic pollution highlights the urgent need for action to reduce plastic production and create protected spaces for wildlife to recover.

Sharks can get entangled in plastic debris, making it difficult to swim, catch food or avoid predators

Sharks are incredibly fascinating creatures that play a crucial role in maintaining a healthy marine ecosystem. However, their existence is under severe threat due to plastic pollution. One of the significant ways plastic impacts sharks is by entanglement, making it difficult for them to swim, catch prey, or evade predators.

Sharks, like many other marine animals, can become entangled in plastic debris, which can have devastating consequences. This entanglement impedes their movement, making it difficult for them to swim freely and efficiently. Imagine trying to swim while being tied up with ropes or straps—it becomes a challenging and exhausting task. This loss of mobility not only affects their ability to catch prey but also puts them at a greater risk of becoming prey themselves.

Sharks that are entangled in plastic are at a higher risk of predation as they are unable to escape potential threats. Their slowed movement makes them easier targets for predators, reducing their chances of survival. Additionally, the plastic debris can act as a hindrance, making it difficult for them to manoeuvre quickly and effectively to catch their own prey. This disruption in their hunting abilities can lead to a decrease in their food intake, affecting their health and survival.

The issue of entanglement is particularly severe with discarded fishing gear, such as nets and lines, which are designed to trap and restrain marine life. Sharks can accidentally swim into these abandoned nets and become trapped, unable to free themselves. Over time, as they continue to grow, the nets can dig deep into their flesh, causing grievous wounds and even scoliosis, as observed in the case of a shortfin mako shark.

Moreover, entanglement in plastic debris can lead to drowning for some sharks. They may become trapped and unable to reach the surface to breathe, ultimately resulting in suffocation. This tragic outcome further highlights the deadly consequences of plastic pollution on shark populations.

To address this issue, it is essential to reduce the amount of plastic waste entering our oceans. This can be achieved through a combination of personal responsibility, such as reducing plastic consumption and proper waste disposal, as well as stricter regulations and policies on plastic production and disposal by companies and governments. By working together, we can help protect sharks and preserve the delicate balance of our marine ecosystems.

Microplastics are often mistaken for food by zooplankton, which are then consumed by sharks, entering their food chain

Microplastics are a huge threat to marine life, including sharks. Microplastics are often mistaken for food by zooplankton, which are then consumed by sharks, entering their food chain.

Microplastics are small plastic particles, usually defined as those less than 5mm in size. They can be manufactured in this size, or they can be the result of the breakdown of larger pieces of plastic in the ocean. This breakdown can be caused by mechanical erosion, the action of winds and waves, or by physical abrasion against sediment particles.

Zooplankton are tiny organisms that feed on phytoplankton and detritus. They are a crucial food source for many marine creatures, including sharks. Unfortunately, due to their small size, zooplankton often mistake microplastics for food. This means that they end up consuming plastic particles, which can then enter the food chain. Once ingested by zooplankton, microplastics can be passed on to larger organisms that feed on them, including sharks.

A study by Will McCallum of Greenpeace UK found plastic particles in the stomachs and digestive tracts of demersal sharks in the North Atlantic Ocean. These sharks feed on a range of organisms, including zooplankton, and the study found that the presence of microplastics in their systems was likely due to bioaccumulation up the food chain. This means that the sharks had ingested zooplankton that already contained plastic particles, which then passed into the sharks' systems.

The impact of microplastics on shark health is still not fully understood. However, it is known that microplastics can block digestive tracts, damage stomach linings, and cause a decrease in appetite, leading to starvation. They can also carry toxic chemicals, which can have harmful effects on the health of sharks and other marine organisms.

To reduce the impact of microplastics on shark populations and marine ecosystems, it is essential to address the root cause of the problem: plastic pollution. This involves reducing plastic consumption, improving waste management practices, and implementing policies to regulate the production and use of single-use plastics.

Frequently asked questions