16 Biggest Problems For Our Oceans, Coasts & Marine Life

Oceans make up a large % of the Earth’s total surface area

Further to that, oceans and their wildlife are important in a number of ways for humans and the ecosystems and life on Earth.

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

This guide compliments our separate guide on some of the potential solutions to conserve oceans and address these problems.


Summary – Biggest Potential Problems For The World’s Oceans, Coast, & Marine Life

Potential Problems

A summary list of the potential 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, dumping into the ocean, and general water pollution

Irresponsible fish farming

Overall reduction in biodiversity

Offshore drilling and mining

Illegal, unreported and unregulated fishing

Melting or shrinking ice caps

Ocean shipping

Lack of protection

Coastline tourism and development


Potential Solutions

Read more about the potential solutions to these issues and others in this guide about how to save the world’s oceans


1. Overfishing

Overfishing can involve fishing total fish population biomass’ to the point of decline in an individual fishery

Overfishing might also involve the fishing of certain species past the sustainable population size within a given fishery

One of the effects of overfishing is that it can threaten and endanger certain species.

Species endangerment or a significant decrease in a species’ population can impact the ecosystem and food chain, because one species or type of animal might depend on another to survive, or the endangered species might fulfil specific functions within the ecosystem.

This has a domino effect because the marine ecosystem relies on healthy numbers of organisms and marine life to support one another. Humans also rely on healthy populations of fish and other marine life to make a living from and eat.

In some instances overfishing can lead to the partial collapse of a fishery

Two modern examples of overfishing in some fisheries might be the overfishing of bluefin tuna and the orange roughy

Certain fishing techniques can pull too many fish, or too many non-target fish. By-catching is a separate issue though whereby unwanted marine life is pulled in the nets whilst trying to catch other marine life.


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

These practices 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 and ghost fishing might be two examples of potentially destructive fishing practices

Another example is drag net fishing that can destroy coral, and endanger dolphins and other marine life.


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 Being Killed, & Animals 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 i.e. 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 emissions from natural sources on Earth.

But, certain human activity also emits CO2 emissions (mainly from the burning of fossil fuels), and the ocean also absorbs this additional CO2.

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)


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 potential effects of a changing climate 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

Coral can also be vulnerable to ocean acidification, land based pollution that gets into the ocean, and other threats


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 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.

One example of solid waste pollution in the ocean is plastic pollution.

Plastic is actually one of the most common waste materials found both on beaches and in the ocean.


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.


Dumping of toxic waste and hazardous waste into the ocean can also be a waste pollution issue.


9. Irresponsible Fish Farming

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.

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


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

Along with the world’s soils and the world’s tropical rainforests, the world’s oceans have some of the highest concentrations of biodiversity.

Ocean biodiversity may decrease or be impacted negatively as a result of other problems, such as overfishing, endangerment of different marine life species, destruction of habitats, and more.


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 Or Shrinking Ice Caps

Melting or shrinking ice caps might produce some problems, but may also have some benefits.


The shrinking Arctic ice cap is a problem for polar bears [and] There is a need to manage fishing in waters that were formerly under the ice for most of the year (boatinternational.com)


However, boatinternational.com also indicates there could be some benefits of a shrinking ice cap: ‘…[the shrinking Article ice cap might also introduce] species new to the region such as mackerel and Arctic cod and could in theory increase the amount of human food available.


Some of the other potential effects of melting sea ice are included in this guide.


14. Ocean Shipping

It’s worth noting that ocean shipping and transport contributes significant value to the world economy.

However, it may also present some problems.


Ocean shipping can result 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

There are economic benefits to oceanside tourism, but there can be tradeoffs too.


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


Other Potential Problems For The Ocean

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


Potential Problems For Beaches & Coastlines

Erosion can also be a problems for beaches and coastlines, and beach nourishment might be one way to address this.


Potential Solutions To Ocean Related Problems

Read more about the potential solutions to problems facing the ocean in this guide



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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