The Shark Crisis and how microplastics are harming Marine Mammals
by Ankita Bhattacharya
They were once these fearsome silver whites, speedy fins and jaws that thrived down the deepest ocean beds and across bays and beaches. Beginning with the Whale sharks through the great whites, sharks have always helped balance the marine ecosystem by maintaining the population of certain species in healthy levels.
They are still around, however in much fewer numbers and in far greater distress. Recent years have seen the decimation of shark population from ‘endangered’ to ‘critically endangered’ to ‘threatened’. What is more alarming than the rapid decline in shark numbers, is the pathetic condition of the living ones.
These ferocious and powerful animals are heading towards near-extinction due to indiscriminate hunting and plastic pollution. Here’s how we’ve let these gorgeous creatures down:
The Microplastics Hazard
Plastic fibers or particles of thickness 5mm or less are termed microplastics. They are either manufactured or formed out of larger chunks of plastics when they are subjected to UV rays, wind and waves.
Microplastics are of greater threat to the ocean and marine lives than their macro parts. Upon disintegration, the microplastics now possess a larger binding area to release toxins. Secondly, the smaller particles are now viable for consumption by zooplanktons and fish larvae which constitute the bottom of the marine food chain. With small fish feeding on zooplanktons and larger fish on smaller ones, the microplastics find their way into larger fish.
As a classic example: the pandemic situation has forced the petrochemical companies to amp up the production of masks and protection gear. These single-use, disposable protection wear made out of plastic ends up in the ocean in tons. The fish, turtles and seals are easily deceived by the shape of the masks for jellyfish.
With the several thousand tons of plastic waste afloat the oceans and natural scavenging of marine animals this plastic ends up in their food tract. This may eventually cause their death by starvation in some animals. In others, the ingested plastic disintegrates into much smaller microplastics which release toxins and are a direct threat to their lives and an indirect threat to the higher animals preying on these animals.
Either way, the plastic gains entry into the food chain of the higher animals including sharks. Having said that, direct ingestion is not a threat to the sharks, in particular. They can invert their stomachs to release inedible substances.
There are several hundred recorded instances of shark deaths from getting caught into drifting nets or plastic waste, although the actual number is feared to be far higher.
Discarded or lost fishing gear cause the majority of the entanglements. These do not result in immediate death but certainly raise a red flag on animal welfare concern.
In one tragic case, a shortfin mako shark (photographed) was caught in a fishing rope and continued to grow in spite of it. This resulted in the fishing rope digging deep into its flesh and causing scoliosis in its spine.
Despite the horrific, plastic entanglements are still not considered a major threat to the future of shark population. That would still be owing to reckless killing. But the animal welfare concerns over grievous wounds, due to entanglements, leading to eventual death are under the scanner.
Researchers have reported, about 100 million sharks are hunted by humans every year. A very popular myth says ‘Sharks don’t get cancer’. Dealers of shark cartilage propagate such untruths to feed to a world pining for cancer drugs.
However, scientists have known for over 150 years that sharks do get cancer. Photographs from Neptune Island, South Australia show a great white shark with cancerous tumor on its lower jaw. Also researches have never confirmed that shark cartilage can be effective in treatment for cancer.
Shark hunting is also attributed to a demanding market for shark fins as a highly palatable soup. Imposition of stricter laws on shark hunting by the governments could help restore the oceanic eco-balance. More effectively, though, we could help by caring.
By choosing reusable over disposable, single-use variants, we help lessen the plastic waste.
We could save the planet by saying ‘NO’ to animal cruelty. Conscious awareness and humane thinking could save us.