What Are the Indicators of Ocean Health?

Any committed beach lover who enjoys swimming in the sea will know this popular wisdom saying: “if you see sea urchins at the beach, then it means that the waters are very clean.” Regardless of the scientific validity of this claim, this highlights that we have been looking out for signs and metrics to evaluate how clean our seas and oceans are even before the advent of modern technology.

It is clear that if our oceans are healthy, marine life will be healthy and so we can enjoy eating fish and seafood. If our seas and beaches are clean, we can enjoy swimming in them. But how can we measure ocean health, when it occupies such a vast space of our planet and goes into great depths, some of which we have yet to explore?

Frightening discoveries regarding the health of our oceans

We often hear about researchers identifying chemical pollution in our seas with chemicals building up in mammals and other marine organisms.

A very recent example is the discovery that one of the UK’s last killer whales was contaminated with shocking levels of polychlorinated biphenyls (also known as PCBs), toxic chemicals which have been banned globally since the 1970s but are still found in the environment because they persist and accumulate in fat cells [1].

Lulu, as the animal was called, was found dead on the Isle of Tiree in Scotland last year after becoming entangled in fishing lines. Tests have recently proven that her body contained among the highest levels of PCBs ever recorded: they were 20 times higher than the safe level scientists expect cetaceans would be able to manage [1].

Other stories often reported by the media include the ever-decreasing yields of fish, ever increasing levels of marine litter (plastic litter is estimated to outnumber fish in the sea by 2050 unless we take action [2]) or the effects of climate change on unique ecosystems such as Australia’s Great Barrier Reef (Australia’s scientists discovered this year that another 8,000 km had been damaged leaving the ecosystem in a “terminal state” [3]).

Alarming as this evidence is, it does not provide a holistic understanding of ocean health. We need to have a measure that helps us determine the health of our oceans for several reasons:

• to assess the state of our oceans;
• to determine what metrics we should be focusing on to improve ocean health;
• to measure progress and the impact of policies on improving ocean health.

Why do healthy oceans equal healthy people?

8 June is World Oceans Day offering us all an opportunity to reflect on the importance of our oceans for our own health and well-being. If you really start to think about it though, and consider how critical oceans are, you will quickly realize that one day of appreciation a year seems very inadequate; especially when 40 percent of our global oceans are ‘heavily affected’ by human activities [4].

Even if you never have a chance to see or touch the ocean, the ocean touches you with every breath you take, every drop you drink, every bite you consume. Everyone, everywhere is inextricably connected to and utterly dependent upon the existence of the sea.

—Sylvia Earle – National Geographic’s veteran marine biologist

In the first place, our seas are critical to our livelihoods. They are particularly crucial for people living in coastal communities, who represented 37 percent of the global population in 2010. Oceans provide jobs in areas of the economy such as fishing or tourism and research, as well as subsistence and income [4].

Healthy oceans equal healthy fish for the world’s poorest

Our oceans contribute to food security. Fish, shellfish and seafood are key food categories for big parts of the population. However, if not sustainably managed, fishing can damage fish habitats.

Ultimately, overfishing impairs the functioning of ecosystems and reduces biodiversity, with negative consequences for sustainable social and economic development. Based on an analysis of fishing stocks, world marine fish stocks operating within biologically sustainable levels declined from 90 percent in the mid-1970s to 69 percent in 2013 [5].

What is particularly significant is that a decline in fish populations poses greater risks for poor people in developing countries. According to the United Nations, 820 million people do not have enough to eat [14]. 460 million of these people live in major fish-dependent nations, countries like the Philippines, Indonesia, and Mozambique. Seafood is their crucial source of healthy protein and important micronutrients like iron, omega-3 fatty acids, zinc and vitamins A and B12 [6].

Lack of access to these nutrients may create dire health consequences for fish-dependent populations.

A study found that as much as 10 percent of the world population, especially concentrated in equatorial developing nations, could face micronutrient and fatty-acid deficiencies due to declines in the availability of fish. From this point of view, saving the oceans is no longer a conservation goal only; it’s critical to ensuring global food security [6].

Healthy oceans equal healthy terrestrial ecosystems

Our seas and oceans have provided us with all these benefits while at the same time absorbing large chunks of the environmental implications our polluting activities have created. Since the beginning of the industrial revolution, the ocean has absorbed about one third of the carbon dioxide released by human activities, thereby mitigating the full impact of climate change.

However, this comes at a steep ecological price. Greenhouse gas emissions are increasing the acidity of the ocean and if we continue business as usual, the ocean could become 150 percent more acidic by 2100 [4]. This would be catastrophic for all ocean life as it would lead to a reduction of plankton, threatening the survival of these organisms and unique ecosystems.

Beyond climate change, our oceans protect coastal areas from flooding and erosion. In fact, coastal and marine resources contribute an estimated $28 trillion to the global economy each year through ecosystem services. But there again, pollution of both land and seas is a threat in many coastal regions.

What is more, since marine ecosystems are part of hydrological systems, the effects of such pollution are often felt far from their source. In many coastal communities, pollution and eutrophication caused by nutrient runoff from agriculture or industries in water causes dense algae growth and mass dying of aquatic animals.

The five large marine ecosystems most at risk from coastal eutrophication, according to a global comparative assessment undertaken in 2016 as part of the Transboundary Water Assessment Programme, are the Bay of Bengal, the Gulf of Mexico, the North Brazil Shelf, East China Sea and South China Sea [4,5].

Identifying indicators of ocean health

It is for those very important reasons that marine researchers from across the world worked hard to create an index that assesses overall ocean vitality [7].

The Ocean Health Index, as it is called, is made up of ten different measures that are aggregated into a single score which gives an indication as to how well our seas are doing.

The metrics tracked features such as food provision, carbon storage, tourism value and biodiversity so that both the needs of humans and ecosystem sustainability can be reflected.

The index was completed in 2012 and it was the result of more than 65 scientists, economists and environmental managers working together and using information from over 120 scientific databases. Since then, more than 25 countries and regions have embarked on independent Ocean Health Assessments using the index [8].

Creating this index, however, was by no means straightforward. Jane Lubchenco, head of the US National Oceanic and Atmospheric Agency (NOAA) in the US, believes that the index is just a first great attempt at understanding what the trade-offs are for management decisions, but there is definitely a need for improvement.

The current state of the ocean health

In an initial assessment, our oceans scored an average 60 out of 100, which would indicate that there are some serious concerns regarding ocean health. What is more, almost one-third of the world’s countries scored below 50. Most recent data, the fifth assessment of the index, it seems that most scores have not changed much from 2012 to 2016 [9].

Specific metrics that are consistently scoring low are “tourism and recreation” which highlights that countries are not utilizing in a sustainable way the benefits derived from the tourism sector.

In addition, low scores of the metrics of “food provision” and “natural products” confirm that many regions are overfishing or are not using the full potential of the sea to produce more food sustainably.

A key limitation of the index here is the issue of poor-quality data or no data at all! This limits the ability of researchers to provide accurate estimates of the status of fish stocks and fisheries overall.

It is also important to note that the index measures key metrics such as “biodiversity” and “coastal protection” based on data from the 1980s. Therefore, while biodiversity scored a high 91 points, this means that damage equivalent to 9 points was effected over the course of the last 30 years. The same applies for coastal protection which scored 87.

This is an alarming trend – if we continue at this pace, by the end of the 21st century both these metrics will have decreased to a very concerning level [10].

5 Ways to boost ocean health

With our oceans being critical for maintaining the Earth’s carbon balance, for sustaining key ecosystems, and for providing for people whose livelihoods depend on fishing or marine tourism, it is imperative that we find a way to boost ocean health.

If our oceans were a person then they would be “anemic and feverish, their arteries clogged and blood chemistry out of whack.”

Luckily, there is a way to help and here are five ways to boosting ocean health the best we can.

#1 Preserving the ocean wealth

Our oceans offer a bounty of benefits and a plethora of natural wealth. The most well-known of those are fish stocks and sea food industry. These industries play a critical role in many economies as a source of food, nutrition and livelihoods.

Their importance is critical in poorer communities and developing countries but it is also an engine for economic growth: according to the World Economic Forum, the global trade in wild-caught fish is valued at around $90 billion while the catch sector directly employs around 40 million people [11].

It is therefore imperative that we fish at sustainable levels to ensure stocks are replenished so that we continue to benefit from our oceans in the long term. Given that today 20 percent of marine catches are illegal, there is still some way to go before we have full product traceability and transparency in fish supply chains to help address this problem [12].

Next time you are at a supermarket or the fishmongers, take care to ensure you are buying fish or seafood that has been verified as sustainably sourced. If your local shops don’t offer such a choice, ask for it and help drive more sustainable consumer choices!

But our ocean’s wealth is not just the fish and seafood we can eat. Oceans are home to a myriad of unique species and ecosystems, such as coral reefs. But there is still exploitation, often illegal, of these resources. It is therefore important to avoid purchasing souvenirs made from corals, tortoise shell hair accessories and shark products.

#2 Keeping our oceans clean

It is true for our planet in general, but currently our ocean is suffering a lot from pollution. It is not only the impact of fossil fuel extraction, fishing activities or transport which are causing pollution as well as disturbance of fish and mammals such as dolphins; marine litter and in particular plastic is becoming a key threat.

To keep our oceans clean we need to work beyond our seas. We need to decarbonize our energy system, so that we no longer need to deploy floating rigs and we need to optimize marine transport to cause minimal disturbance.

It is also important to note that when it comes to the deployment of offshore renewable energy, we need to be equally careful to ensure that seabird populations and other marine animals are not impacted by their presence.

Tons of used plastic ends up in the sea where it damages ocean life. The only way to stop this from happening is to ensure all plastic – across the world! – is properly disposed of in recycling facilities. This is a rather tall ask and we cannot afford to wait for this to become a reality.

You can instead help ocean life right away by eliminating plastic from your life as much as you can. The reality is that a lot of plastic pollution comes from single-use items (plastic cutlery and cups) and plastic bags – all items we could easily live without.

#3 Improving coastal environments

As is the case with marine litter, most of the damage comes from activities that happen on the land. There is also a link between healthy coastal environments and oceans. To preserve the latter, we need to ensure we keep the former in a good state too!

This means we need careful planning when it comes to developing, for tourism or otherwise, our coastal areas. This is important to ensure that our marine environment remains pristine and its functions largely uninterrupted by our activities.

For example, effective measures to treat sewage, manage industrial waste and limit agricultural run-off are key to a healthy ocean.

#4 Increasing ocean productivity sustainably

While a lot of emphasis is rightly placed on conservation of our marine wealth, the potential of “blue growth” cannot be ignored. There are many who believe that our oceans can provide for more of our food, for example through aquaculture.

These opportunities need to be carefully looked at particularly as global demand for fish is increasing and catches from wild-capture fisheries is levelling off. But we must not forget that efforts to increase marine farming will only be successful if the demands they make on the environment are managed.

Although freshwater aquaculture currently makes about 70 percent of farmed fish and is likely to remain so, mariculture has the potential to grow in many developing countries. Seaweed and shellfish culture seem promising given their small environmental footprint.

#5 Reducing greenhouse gas emissions

It goes without saying but this list would not be complete without a reference to the importance of limiting greenhouse emissions, and therefore addressing climate change, as a way of restoring ocean health.

Oceans and climate are inextricably linked in a two-way manner: oceans play a fundamental role in mitigating climate change as they are a major heat and carbon sink. But they also bear the brunt of climate change which is leading to growing acidification, sea level increase, and changes in temperature and currents.

So when you are choosing low carbon technologies such as hybrid or fully electric vehicles, public transport or cycling; when you are purchasing high energy efficiency white goods; and when you are opting for electricity operators that utilize renewables, you are helping mitigate the impacts of climate change on our oceans too!