Plastic In Fish: A Worrying Reality

Plastic ingestion is a growing problem for fish, with a study from 2021 revealing that the rate of plastic consumption by marine fish has doubled in the last decade and is increasing by more than 2% a year. Microplastics, which are tiny plastic particles, are now found everywhere in the ocean, from the surface to the deepest reaches, and are ingested by fish. This has raised concerns about the long-term health of fish and the potential impact on humans, as fish are a source of food for billions of people worldwide.

Microplastics are found in 75% of commercial fish species

The presence of microplastics in fish is a growing concern for scientists and environmentalists alike. A study published in the Marine Pollution Bulletin revealed that microplastics are found in 75% of commercial fish species. The study, conducted by scientists from New Zealand and Australia, examined 155 fish from 10 species, including Red Cod, caught off the Otago coast. It found an average of 2.5 plastic particles per fish, with microplastic fibres being the most commonly ingested, particularly in blue, black, and red. The most common plastic polymers ingested were polyethylene and polypropylene.

The study's findings highlight the widespread nature of plastic pollution in our oceans and its impact on marine life. Both bottom-dwellers and pelagic fish were found to be equally affected, indicating that plastics are suspended throughout the water column. This is supported by another global analysis, which found that two-thirds of all marine and estuarine fish species had ingested plastic, with 210 of them being commercially fished species.

The presence of microplastics in commercial fish species has raised concerns about the potential health risks for human consumption. While the immediate impact on fish populations is not noticeable, the long-term effects of bioaccumulation of plastics and their associated chemicals are unknown. Some studies have shown that the ingestion of microplastics can cause biological changes in fish, including altered liver function and changes in their gut microorganism community.

Furthermore, the impact of microplastics on the food chain and human health is a growing area of research. Microplastics have been found in the gastrointestinal tract, gills, and muscle tissue of fish, indicating the potential for human consumption of these particles. Studies have estimated that adults may intake up to 842 microplastic items per year through fish consumption alone. The potential toxicological effects of microplastics on humans are still not fully understood, and more research is needed to assess the risks associated with the presence of microplastics in commercial fish species.

The rate of plastic consumption by marine fish has doubled in the last decade

Plastic ingestion by marine fish is a growing problem. A study published in the journal Global Change Biology revealed that the rate of plastic consumption by marine fish has doubled in the last decade and is increasing by more than 2% a year. This is particularly concerning given that billions of people around the world rely on seafood for sustenance and financial security.

The study, led by Matthew Savoca, a postdoctoral research fellow at the Hopkins Marine Station, analysed data from 129 studies on 171,774 individuals of 555 species of marine and estuarine fish. The results showed that two-thirds of all species had ingested plastic, with 210 being commercially fished species. This number is likely an underestimate, as there were still 148 species with no record of plastic consumption.

The likelihood of plastic ingestion was found to be higher in places with an abundance of plastic in surface waters, such as East Asia. However, fish type and behaviour also play a role, with active predators at the top of the food chain, such as hammerhead and bonnethead sharks, ingesting the most plastic. Grazers and filter feeders consumed the least. The study also found that the rate of plastic consumption decreased with depth.

The presence of microplastics in fish habitats has been shown to affect fish's ability to ward off viruses, with fish exposed to microplastics and a deadly fish virus dying more often than those not exposed to microplastics. Additionally, microplastics can alter liver function and change the gut microorganism community in fish. The long-term health effects of microplastic ingestion on fish are still not fully understood and require further research.

Active predators ingest the most plastic

Plastic pollution is currently the largest global threat to marine life, with 10-20 million tonnes of plastic ending up in our oceans each year. Marine animals, including mammals, birds, turtles, and fish, are all affected by plastic pollution. A recent study found plastic, mostly in the form of microfibers, in the guts of a quarter of fish sold in California markets. This is a concerning finding, as it indicates that plastic is making its way into the human food chain.

Active predators at the top of the food chain, such as hammerhead and bonnethead sharks, have been found to ingest the most plastic. This is because, in addition to accidentally consuming plastic while feeding, they also ingest any debris inside their prey. This phenomenon is known as trophic transfer, where toxins consumed by smaller creatures are stored in their body tissue and passed up through the food chain.

The presence of plastic in the diet of these fish can have various negative consequences. For example, it can affect their reproductive success and population stability. In male fish, exposure to certain chemicals through plastic ingestion can lead to feminization, resulting in reduced breeding activity. Additionally, plastic ingestion has been linked to abnormal behavior in fish, such as slower eating and hyperactivity, making them easier prey for higher-level predators.

While the specific health effects of consuming plastic-contaminated fish are not yet fully understood, research suggests that the bioaccumulation of plastic and its associated chemicals may cause health issues in fish. A study on farm-raised yellow perch found that those fed contaminated feed had lower amounts of protein and minerals compared to those on a plastic-free diet. This indicates that the presence of plastic may interfere with the absorption of essential nutrients.

Microplastics can damage the gills of shellfish

Microplastics are a global issue due to their toxic effects on fish and humans. They are ingested by many species of wildlife, including fish and shellfish. The presence of microplastics in shellfish species can cause adverse effects on the organisms themselves, which raises potential health risks for humans who consume them.

Shellfish and other marine organisms that are consumed with intact gastrointestinal tracts are of particular concern because they accumulate and retain microplastics. The average number of microplastics ingested from shellfish is estimated to range from 2,602 to 16,288 items per person per year. A top European shellfish consumer may eat approximately 11,000 plastic particles annually.

Microplastics can enter the food web when they are consumed by zooplankton, leading to bioaccumulation and trophic transfer. This increases the likelihood that fish, shellfish, or other species will consume them, with potential negative consequences for human health.

While the specific mechanisms are still being studied, research has shown that microplastics can cause tissue damage, oxidative stress, and changes in immune-related gene expression and antioxidant status in fish. These effects can lead to neurotoxicity, growth retardation, and behavioural abnormalities. Similar toxic effects may occur in shellfish, which could have implications for human health when they are consumed.

Microplastics may affect the health of fish and humans

Microplastics are present in all fish habitats, and ingestion of microplastics is common among fish species. A study found that 75% of commercial fish species had ingested microplastics, with an average of 2.5 individual plastic particles per fish. Another study of 555 species of marine and estuarine fish found that two-thirds had ingested plastic, with 210 of those species being commercially fished.

The ingestion of microplastics has been shown to impair the health of fish. A study by NIST found that fish exposed to microplastics and a deadly fish virus died more often than those that were not exposed to microplastics. The study also raised concerns about the long-term health of fish if the microplastics crisis is not addressed. Another study found that organic contaminants sorbed to microplastics affected the early life development of Medaka fish.

Microplastics can affect the health of fish by impairing their growth, disrupting their reproductive systems, and increasing mortality rates. They can also bioaccumulate in fish, leading to health problems. Certain species are more affected by plastic ingestion than others. Active predators at the top of the food chain, such as hammerhead and bonnethead sharks, ingest the most plastic. Grazers and filter feeders consume the least.

The ingestion of microplastics by humans through the consumption of fishery products is a potential health risk. Fishery products are a significant source of microplastics in the human diet. While most fish are eviscerated before consumption, reducing the risk of microplastic ingestion, there are exceptions, such as bivalve mollusks, small crustaceans, and some small fish species that are commonly eaten whole. Microplastics can reach the gastrointestinal tract, causing oxidative stress, cytotoxicity, and translocation to other tissues. They can also release chemical substances, including organic and inorganic compounds, and act as carriers of microorganisms.

The potential toxic effects of microplastics on humans have been hypothesized, but the data is currently insufficient to assess the risks accurately. However, it is known that microplastics can contain additive chemicals and persistent organic pollutants (POPs) such as polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) that may be harmful to human health.

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