70% of the Earth’s surface is covered by ocean and is home to 700,000-1,000,000 species, including my personal favorites, dolphins and orcas. It offers a wide array of habitats for marine creatures ranging from sea grass, mangroves, coral reefs and the water column. Unfortunately, our beautiful oceans are used as a dump site with 80% of pollution that ends up in the ocean coming from land-based activities. Effluent from factories and industries are major sources of pollution in rivers, a main conduit of pollution that winds up in oceans.

Pollution and other human activities are posing a serious threat to the state of the ocean and its corresponding marine life. Here are the major threats:

Climate Change

Climate change is inarguably the worst threat to marine life. Global warming is causing changes to the ocean chemistry and this in turn will affect marine species that depend on the stability of the ocean. One of these changes includes warming of the ocean water which reduces the ability of oxygen to dissolve into the sea water leading to diminished oxygen levels in the ocean for marine life. In addition, coral reefs are sensitive to warming oceans; the warm temperatures lead to coral bleaching and eventually death.

Coral bleaching occurs when colourful, microscopic algae called zooxanthellae is expelled by corals due to warming waters. The zooxanthellae live in the coral and the two have a mutually beneficial relationship; they depend on each other for survival. Once the algae are expelled the coral fades (turns white) and appears to be bleached. Without the algae the coral will eventually die. The Great Barrier Reef, the world’s largest reef is almost halfway bleached.

Secondly, ocean acidification caused by increased carbon dioxide in the atmosphere dissolving in the ocean leads to the eroding of shells of animals such as lobster, oysters, and shrimp.

Thirdly, climate change is also causing rising sea level which affects the habitat of many marine species.

Over-fishing

Fishing is not inherently bad; it only becomes an issue when we catch more fish than can be replenished naturally. This leads to overfishing. 31% of fish stocks are already depleted (overfished) according to FAO.

The main fishing gear used for commercial fishing is drift netting and trawling which has contributed to another problem, by-catch. By-catch is the unintentional catching of sea creatures when fishing for a different species (fish and shellfish). Examples of marine animals that get entangled in the gear are whales, dolphins, turtles, seals, sharks, and seabirds. In fact, a significant number of marine creatures are killed unintentionally by commercial fisheries.

Plastic waste

There are more than five trillion pieces of plastic swimming in our oceans. All the plastic bottles, straws, bags, and packaging material we have ever used wind up in oceans. It is estimated that 8 million tonnes of plastic are discarded into our oceans each year. The danger of all this plastic in our oceans is that it can result in choking and entangling of sea creatures. In addition, the plastic breaks down into micro-plastics that sea creatures mistake for food. This is bad because large amounts of plastic are found in the bellies of whales, and tiny fish feed on micro-plastics which can lead to biomagnification. Biomagnification is a condition in which compounds (pollutant) accumulate in the tissue of an organism as it travels through the food chain.

Agriculture and Sewage discharge

When nutrients are discharged into oceans in excessive amounts as sewage, fertilizers, or nitrogen oxides from burning fossil fuels, this can lead to eutrophication. Eutrophication is the excessive growth of marine plants such as algae which causes an algal bloom. This limits the sunlight that will penetrate into the water and reduces the availability of oxygen. When oxygen levels plummet it affects marine creatures, coral reefs and other vital habitats. Sewage tends to be the main source of nutrients in cities and agriculture dominates in rural areas.

Coastal development

Coastal development is change caused by human activities on an area of land adjacent to the coastline. It leads to the destruction of natural land and the fragmentation of coastal habitats. This development includes building structures that are on or near the coast either for protection, business, residential, communication or recreation. Impacts resulting from development are dredging and coral/sand mining for construction material or increased runoff of sediment and pollutants. Currently, 2.4 billion people live within 100km of the coast, putting undue pressure on coastal ecosystems.

Ocean noise

Ocean noise is sound generated by human activity that can obscure marine animals from detecting natural sounds in the ocean. Sources of ocean noise are ships, military sonar and seismic exploration for oil and gas. This is harmful to marine animals such as whales and dolphins because it can interfere with their communication channels. The noise can also prevent other animals from meeting a mate, detecting predators, and finding food.

Deep-sea mining

Deep-sea mining is a potential threat to marine animals. It is the process of retrieving mineral deposits from the deep sea. The depletion of terrestrial deposits of minerals is stimulating interest in deep sea mining. However, they are still in the exploration stage of deep sea mining to assess the size of mineral deposits.

Solutions

The establishment of Marine Protected Areas (MPAs)–to protect and conserve ecologically and biologically significant marine areas by regulating human activities.

On the same note Locally Managed Marine Areas (LMMAs) should be established. These are marine conservation areas managed by the local coastal community. In fact when MPAs and LMMAs are merged, it can increase the conservation effort and enhance interconnectivity between the two which will result in a widespread and better managed conservation area.

Banning of destructive fishing methods such as trawling.

Regulations on overfishing and animals caught as by-catch should be followed and hefty penalties put in place to any organizations that do not adhere to them.

Use eco-friendly and reusable products and avoid single use plastic such as plastic straws, bottles and bags.

Support local marine conservation organizations i.e Local Ocean Trust – Watamu

Conclusion

Clearly, the state of our oceans is critical and a lot needs to be done to conserve them.