16 Biggest Problems For Our Oceans, Coasts & Marine Life

Oceans make up 71% of the earth’s total surface area, and these oceans and their wildlife are important in a number of ways for life on Earth.

As one example, the ocean provides more than half of the oxygen in the atmosphere, and absorbs the most carbon from the atmosphere (protectplanetocean.org)

Further to that, ocean-based businesses also contribute more than $500 billion to the world’s economy (protectplanetocean.org).

In this guide, we look at some of the biggest problems for our oceans, coasts and marine life.

We also look at some potential solutions to address these problems.


Summary – Biggest Problems For Oceans, Coast, & Marine Life, & Potential Ways To Start Solving These Problems



Destructive fishing practices

Predators are being killed, and other marine life are being killed perhaps unnecessarily

Ocean acidification

Coral dying

Ocean dead zones, eutrophication and algal blooms

Mercury pollution

Plastic waste pollution in the ocean, fishing gear dumping, and other types of waste pollution in the ocean

Irresponsible fish farming

Overall reduction in biodiversity

Offshore drilling and mining

Illegal, unreported and unregulated fishing

Melting ice caps

Ocean shipping

Lack of protection

Coastline tourism and development


Potential Solutions

Read more about the following solutions in this guide about how to save the world’s oceans:

Limits and regulations on types and quantities of fishing allowed

More sustainable and ocean friendly fishing practices

Consumers can choose sustainable seafood, or switch to land sourced/produced sustainable food

Better protection of specific ocean species and organisms

Minimizing atmospheric CO2 from humans sources

Minimising (and managing) mercury release from human sources

Aim for more sustainable agricultural practices

Better management and treatment of sewage and waste water (and less dumping of untreated waste water into the ocean)

Aim for more sustainable mining practices

Aim for more sustainable electricity production practices

Aim for more sustainable transport practices

Minimise air pollution

Minimise soil/land pollution and contamination

Minimise plastic waste, fishing equipment and other waste going into the ocean

Reduce freshwater pollution

Reduce run-off, leaching and direct dumping overall, and better manage, treat and dispose of waste overall (that ends up in the ocean)

Explore the benefits of on-shore fish farming and aqua culture either as an alternative or complement to ocean fishing

Aim for more sustainable offshore drilling and mining practices

Invest in alternate income sources for citizens in countries where they rely on destructive ocean tourism to make a living

Regulate beachfront development to minimize environmental damage


1. Overfishing

Reduces marine wildlife numbers

Can threaten and endanger certain species (such as bluefin tuna and the orange roughy)

Species removal upsets the ecosystem and food chain because one species or type of animal might depend on another to survive

Certain fishing techniques pull too many fish, even unwanted fish, each catch (bycatching is a separate issue whereby unwanted marine life is pulled in the nets whilst trying to catch other marine life).

They aren’t sustainable.


The Food and Agriculture Organization estimates that over 70% of the world’s fish species have been entirely exploited or depleted

– worldoceansday.ca


2. Destructive Fishing Practices

Destructive fishing practices may damage or degrade the ocean floor, and important parts of the ecosystem like marine life habitats, coral, and so on

It may also have a damaging impact on marine life directly in someway, via injury or death

These practices can relate to how catches are pulled, and sometimes also lost or discarded gear


Bottom trawling destroys the sea floor habitat

– treehugger.com


Ghost Fishing is another issue where lost or discarded fishing gear continues to catch fish and other marine life

– worldoceansday.ca


3. Predators Are Being Killed, & Animals Are Being Killed For Specific Body Parts

Firstly, catching predators can upset the food chain in the ocean, as predators can help regulate population numbers of animals and organisms lower on the food chain. There can be a domino effect.

Second, killing certain species for only one body part causes the issue of waste, where only the one body part might be used instead of as much of the catch as possible

Some specific cultures have beliefs around the medicinal, health based, or spiritual based properties of a certain species or body part


Sharks in particular can be killed for their fins (for fin soup) … and the result is two fold [as sharks can be a predator, but there’s also waste]

Certain wildlife are [also] fished for their health benefits of oils

– treehugger.com


Whaling can be another issue – whales being killed causes issues in the marine ecosystem elsewhere

– worldoceansday.ca


4. Ocean Acidification

The ocean absorbs CO2 naturally on Earth, but humans have also been responsible for a lot of excess CO2 emissions (mainly from the burning of fossil fuels)

Ocean acidification happens when seawater absorbs this excess carbon dioxide, and it dissolves in the water.

The result is the ocean’s average water pH levels getting lower, and it becomes more acidic.

Marine life are at risk if they can’t adapt to more acidic conditions

Another contributing factor to ocean acidification can be eutrophication, which is explained below in this guide.


In the past 200 years alone, ocean water has become 30 percent more acidic

– ocean.si.edu


… extra CO2 is being absorbed by the ocean and shellfish, coral and other species are at risk of being threatened and eliminated if they can’t adapt quickly enough

– treehugger.com


Apart from mitigation measures of decreasing emissions, another strategy tried to address acidification is geo-engineering:

Geo-engineering has been tried with the ocean – limestone to reverse pH levels, and iron filings to help suck up CO2 (treehugger.com)


5. Coral Dying

Coral helps support small marine life in various ways, such as providing a habitat and a home

This means coral indirectly supports large marine life and humans, as both rely on small marine life.

One of the effects of climate change (due mainly to carbon emissions from fossil fuels) is said to be warming ocean waters.

When waters warm, coral can get stressed or die, and this is known as coral bleaching, as coral can change color.

The nytimes.com indicates that some coral can sometimes recover over the course of a decade or more when the water cools again, but sometimes the effects are irreversible or there is a mass die off


6. Ocean Dead Zones, Eutrophication & Algal Blooms

These issues usually happen in coastal areas.

The relationship between dead zones, eutrophication and algal blooms is as follows:

– Eutrophication occurs when excess nutrients, mainly nitrogen or phosphorus, get into the water (a primary cause of this in developed countries is run off from nitrogen and phosphorus based fertilizers used in agriculture, but it can also happen from waste water and industrial waste)

– Excess nutrients in the water leads to accelerated and abundant growth of algae (hence algal blooms) and other aquatic plants 

– Algal blooms can create dead spots and dead zones in the ocean where there a lack of oxygen in those areas. This can happen in several ways, such as algae blocking sunlight, and algae preventing other aquatic life from getting oxygen

– Algal blooms can be followed by hypoxia, which also relates to a lack of oxygen (nationalgeographic.org)


7. Mercury Pollution

Mercury mainly gets into the ocean via the burning of fossil fuels like coal at power plants whereby rain washes it into the ocean, and also from industrial waste/effluent (containing heavy metals like mercury) being discharged into rivers and waterways or directly into the ocean


The smallest marine life absorb [mercury], and it works its way up the food chain to fish like tuna, and into humans

– treehugger.com


8. Waste, Plastic & Garbage Patches

Solid waste like plastic can work it’s way into the ocean in a number of ways.

It can happen via rivers and waterways, via wind, via directly littering, and even out at sea when fishing gear and materials are dumped into or lost at sea.


The Great Pacific Garbage patch is an example of a large gyre of plastic waste in the ocean

Plastic is a material that doesn’t naturally decompose in the environment – it can get ingested by wildlife and entangle them

Plastic also breaks up into micro plastics which are ingested by wildlife

[Plastic also costs money to remove from the ocean]

– treehugger.com


Read more about waste pollution in the ocean here, or specifically about plastic pollution in the ocean in this guide.


9. Irresponsible Fish Farming

Read more about the potential impact of irresponsible fish farming and aquaculture in this guide.

There’s a number of ways that fish farming at sea can impact the ocean such as:

– Nutrient, chemical, medical, excrement, and other forms of waste pollution

– Escaped fish getting into wild habitats (disease transmission is one such potential side effect)

What some people also aren’t aware of is that even fish farmed on land might get a certain % of their fish feed and oils from wild caught fish, so, fish farming currently relies on wild populations.


A few stats about farmed fish production around the world:

In China, 90 percent of fish food production comes from aquaculture (2006)

Overall, aquaculture in the marine environment contributes 34 percent of production and 36 percent of total value

– worldoceansday.ca, and greenfacts.org


10. Offshore Drilling & Mining

There are a number of potential ways offshore mining and drilling for oil and other fossil fuels can impact the ocean, such as …


When oil is extracted from the ocean floor, other chemicals like mercury, arsenic, and lead come up with it.

… [the] seismic waves used to find oil [may] harm aquatic mammals and disorient whales.

Furthermore, the infrastructure projects to transport the oil often create worse problems, eroding the coastline.

– worldoceansday.ca


11. Overall Reduction In Biodiversity

With the above issues, such as threatening of species of marine life, and destruction of habitats, ocean biodiversity is decreasing


The number and variety of living organisms is decreasing

– protectplanetocean.org


12. Illegal, Unregulated & Unreported Fishing

Pirate fishing is a large component of overfishing, and is considered an unsustainable fishing practice


[pirate fishing] causes estimated losses to coastal states of $10 to $23 billion annually.

Illegal fishing is as much as 40 per cent of the catch in some fisheries.

– boatinternational.com


13. Melting Ice Caps

The shrinking Arctic ice cap is a problem for polar bears, but it is also introducing species new to the region such as mackerel and Arctic cod and could in theory increase the amount of human food available.

There is a need to manage fishing in waters that were formerly under the ice for most of the year.

– boatinternational.com


14. Ocean Shipping

Ocean shipping results in oil spills, ship groundings, anchor damage, and the dumping of rubbish, ballast water, and oily waste are endangering marine habitats around the world.

– wwf.panda.org


15. Lack Of Protection

Lack of protection of certain parts of the ocean might be part of an unsustainable way of managing fisheries, but there’s also environmental damage to consider


Only a tiny fraction of the oceans has been protected: just 3.4%

Some areas need more protection than others because of environmental damage and wildlife depletion

– wwf.panda.org


16. Coastline Tourism & Development

Housing, hotels, construction and holiday tourism are all threats to coastlines by damaging habitats and contributing pollution

– wwf.panda.org


Part of a sustainable tourism strategy might involve figuring out how tourism businesses can thrive, whilst at the same time conserving coastlines and oceans


Potential Solutions To Ocean Problems/Issues

Read more about the following solutions in this guide about how to save the world’s oceans:

Traditional ocean conservation strategies

Introduce fishing bans on certain types and species of wildlife, and on predators like sharks

Introduce more sustainable fishing practices and techniques

Consumers can question restaurant servers, sushi chefs, and seafood purveyors about the sources of their fish, and read labels when we buy from store shelves. Treehugger.com has sustainable seafood slideshows that will show you what you want to look for when you’re choosing your next meal, and what to avoid.

Reduce the amount of carbon emissions via human activity (will reduce acidification and coral bleaching and uptake of carbon by oceans)

Decrease our dependence on fertiliser and pesticides in agriculture

Be more careful about what chemicals and toxic substances, as well as what waste water gets dumped into our oceans (currently, about 80% of waste water globally is dumped untreated)

Introduce and maintain more protected ocean areas


Read more about the above issues and problems in this Treehugger.com resource



1. https://www.treehugger.com/clean-technology/the-ocean-has-issues-7-biggest-problems-facing-our-seas-and-how-to-fix-them.html

2. https://en.wikipedia.org/wiki/Ocean_acidification

3. https://oceanservice.noaa.gov/facts/eutrophication.html

4. http://www.greenfacts.org/en/fisheries/l-2/01-fisheries-production.htm#5

5. https://en.wikipedia.org/wiki/Marine_conservation

6. https://wwf.panda.org/our_work/oceans/problems/

7. http://www.protectplanetocean.org/collections/introduction/introbox/oceans/introduction-item.html

8. https://www.boatinternational.com/destinations/of-the-biggest-threats-to-the-oceans–26353

9. https://ocean.si.edu/ocean-life/invertebrates/ocean-acidification

10. https://www.nytimes.com/2020/04/06/world/australia/great-barrier-reefs-bleaching-dying.html

11. https://www.nationalgeographic.org/encyclopedia/dead-zone/

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