A look at issues affecting our oceans and solutions as the globe observes World Oceans Day 8th June 2019

Over three billion people depend on marine and coastal biodiversity for their livelihoods. However, today we are seeing 30 percent of the world’s fish stocks overexploited, reaching below the level at which they can produce sustainable yields.

When I give talks about how we have degraded our oceans to the cusp of catastrophe, people often ask me what they can do. If you want to save the oceans, by all means eat only sustainably sourced fish and stop using plastic shopping bags that become ocean detritus. These things are worth doing. But the problem in our oceans is not something that will be solved through those simple actions alone.

There is no one-size-fits-all solution to improving ocean health, but there are challenges which, if addressed with urgency, will allow the oceans to recover and support our growing population far into the future

1. Overfishing
we have methodically depleted the fish in our oceans. First, we exhausted those we could catch with small boats and rods close to the shore. Then we went further and exhausted the pelagic fish, such as herring and tuna. Then we went deeper, catching species such as the orange roughy, which can live to 150 years and don’t breed until they are 20 years old.

As a rule, it’s unwise to eat things that are older than you are: we should eat food lower down the chain that can reproduce quickly. The oceans are like a deep freezer full of fish, which we’ve now almost emptied.

The good news is that scientists know exactly how to replenish the stocks - by creating marine protected areas, or fish regeneration zones - and how to fish sustainably. This is not a question of knowledge, but of will: we could take action today, if we want to.

2. Coastal pollution
Industrial agriculture is pouring reactive nitrogen and phosphorous into the oceans through every river on Earth, creating what are called “ocean dead zones”.

As with overfishing, we already have the scientific knowledge to rectify coastal pollution quickly by changing our practices on land; it’s about the will to act.

3. Habitat destruction
While marine habitats deal with the pressure of coastal pollution, most notably coral reefs, there are other ways we are systematically destroying the ecosystems that marine plants and animals need to survive. These include clearing mangrove forests for shrimp production and scraping entire ecosystems off seamounts, or underwater mountain ranges, through deep-sea trawling.

Again, these issues are well understood. We could act now.

4. Warming
The rate at which oceans are warming may not sound dramatic - the temperature rise over the past century is estimated at about 0.1 degree Celsius - but that is enough to kill the algae that keep corals alive, move species into new areas, and cause sea levels to rise.

Even if we stopped pumping additional carbon dioxide into the atmosphere, the effects of climate change would continue to play out for a century. That’s not to say that we shouldn’t act on emissions; we must. But we also need to adapt, which will be especially disruptive in relation to rising sea levels. Unfortunately, there is no immediate solution to address global warming

5. Acidification
Like warming, acidification is related to carbon dioxide, which dissolves in oceans to form carbonic acid. The greater the acidity, the less able marine-calcifying organisms are to form shells, disrupting their reproductive process.

Addressing acidification is also an issue of knowledge and will. There are some localities where, for reasons i do not yet fully understand, the water’s pH is lowering more slowly. We need to investigate these areas while protecting them as well as we can by tackling the first three items on this list - the ones where we already know what we have to do.

Returning to my patient analogy, if they’re suffering from multiple illnesses, the chances are they won’t make it - but if you can treat some ailments, they may be able to survive the rest. Under the cumulative weight of acidification, warming, habitat destruction, coastal pollution and overfishing, the ocean environment may soon become fit only for jellyfish.

The threats faced by our ocean planet may seem overwhelming. In the face of pollution, climate change, overfishing, and other daunting problems, what you can do on your own may seem like a drop in the bucket. But if we begin working together now, we can make a huge difference. #SDG14 #Oceans #Conservation #SDGS #EndReducePlasticUse #EcoSystems #Biodiversity #LifeBelowWater #WorldOceansDay