Marine life and ecosystems globally, are subjected to multiple and severe threats. The most prominent of these threats have been caused and are further exacerbated by human activity, negatively altering ocean chemistry, affecting biological processes, and the overall health of the oceans.
Illustrated by Gayatri Jawali
Overfishing is the removal of fish from the oceans at a rate faster than the fish populations are able to reproduce and recover. This is typically due to wasteful, uncontrolled, and exploitative fishing practises carried out to meet the ever-increasing global demands. Wasteful commercial fishing practices further add to this threat by using techniques that also harm other marine life like turtles, sharks, and mammals - many of which are threatened. Constant fishing pressure on any fish species can result in dangerously low numbers that they may not be able to recover from. This has serious consequences, throwing an ecosystem out of balance and resulting in the breakdown of the foodweb that keeps the oceans healthy. As a result, the large section of the global population dependent on fisheries for food and livelihoods also faces uncertainty.
Illustrated by Gayatri Jawali
Plastics make up the largest chunk of litter and pollutants found in the marine ecosystem, contributing nearly 80% to all marine debris globally. Plastics in the oceans include packaging material, food and beverage containers, and microplastics which pose serious threats to marine life. An estimated 8 million tonnes of plastic are discarded into the oceans annually. Plastics are durable, synthetic materials that take hundreds of years to break down, and these affect marine life from corals to large mammals. Animals may ingest plastics and choke, or suffocate, or even die on entanglement in plastic packaging. Microplastics have infiltrated everywhere now, commonly found in seafood consumed around the world, posing serious health risks for people as well.
Illustrated by Gayatri Jawali
Oil spills occur when liquid petroleum is released into the marine ecosystem due to human activity, typically an accident or mechanical failure. It is estimated that thousands of oil spills occur annually, most of which are small spills. However, regardless of their size, these oil spills have severe impacts on the marine ecosystem. Consequences from larger oil spills can be felt for years after they have occured. The leaked oil floats on the surface of the water, creating a slick barrier that prevents exchange of gases andpenetration of light into the environment. This slick prevents marine animals from surfacing to breathe, and coats the bodies and gills of fish and other lifeforms including birds - hindering their ability to breathe, fly and swim. Furthermore, the oil might also be ingested directly or indirectly, resulting in toxicity and death of a large number of species in the area where the spill has occured.
Illustrated by Gayatri Jawali
Ghost nets are fishing nets that have been abandoned, lost or discareded anywhere in the marine ecosystem due to damage, lack of use or other reasons. Ghost or gear are esitmated to make up about 10% of all marine litter, and pose a very serious threat to marine life. They drift in the oceas, continuing to passively catch and entangle unsuspecting marine life. Annually, disturbing numbers of marine mammals, turtles, seabirds, sharks, and other large marine life get caught in these discarded nets and suffer injuries, or die. Larger nets can snag onto corals and choke reefs, causing widespread damage.
Illustrated by Gayatri Jawali
Climate change poses a major threat to marine ecosystems. Rising global temperatures affect marine life and habitats in various ways. Corals are symbiotic associations between microalgae and animals. Rising temperatures stress out the coral, and the algae (that give corals their colour) are expelled, and the corals fade to a greyish-white. Corals can usually recover from this, but in the event of sustained high temperatures, the damage can be permanent. A temperature rise of even 1.5° to 2°C can cause bleaching!