This week for The Update, we hand the pen to Dr Richard O'Driscoll, Chief Scientist - Fisheries at NIWA. Richard has been a scientist at NIWA since October 2000. He holds a PhD in Marine Science from Otago University. He shares his thoughts ahead of World Oceans Day this Sunday.
June 8 is World Ocean Day. The theme is "Wonder: Sustaining What Sustains Us."
The world's oceans do sustain us - they provide the lifeblood of our planet and half of the air that we breathe. The oceans support immense biodiversity, much of which is still to be discovered. Humanity and our actions represent the major threats to our oceans.
Fundamentally, this is driven by human population growth - in my lifetime we have gone from a global population of less than 5 billion to over 8 billion. This growth is out of proportion to the planet's resources.
As well as exploitation of ocean resources, our increasing human population has been responsible for rapid changes in ocean climate, pollution and sedimentation, and destruction of habitat.
The challenge is to continue to allow exploitation to provide the food and other resources we need now, while at the same time trying to reverse destructive trends, so the oceans can continue to be healthy for future generations. In some regions of the world we are doing well, but in others we haven't yet got that balance right.
Across the world's oceans we are facing inter-related threats with climate change, pollution, overfishing, and habitat destruction.
Climate change will impact all the global oceans and there is no going back - we will see changes in species distribution and abundance of species over the next decades, even if we are able to reduce current trends in our emissions. And there will be winners and losers.
I have spent my career carrying out research to help fisheries management prevent overfishing. And this is the issue that we can potentially have most immediate control over. Around the world, we are seeing examples where we can manage fishing pressure and see fish stocks rebound.
Pollution and habitat destruction are most apparent in the coastal ocean, but also extend offshore. Related to this is land use and sedimentation. For example, modification of land for forestry and agriculture and urban development, combined with climate change which increases frequency of extreme weather events has led to increased run-off of sediments and pollutants and destruction of marine habitat.
Fishing can also impact habitat and cause pollution.
However, we have made significant advances in protecting ocean health. The current global focus is on marine protection. The recent David Attenborough documentary Ocean doubled down on this and provided several examples where marine protection has been successful. But marine protection is just one of the management tools we can use to improve ocean health.
The issue I had with Ocean was that this film reduced its focus to one major problem (habitat destruction caused by industrial fishing) with one solution (no-take marine protected areas). It is not that black and white. As noted above, climate change, pollution, sedimentation, and other human activities are all important threats to ocean habitat and interact with fishing.
We also still need management to limit catch. Within country jurisdictions, we have seen many fish stocks rebuild over the past decades. Locally, we have seen large increases in New Zealand West Coast snapper abundance in the past 20 years. In the open ocean, where countries work together through Regional Fisheries Management Organisations, stocks such as Atlantic bluefin tuna have increased. This has occurred without closing areas to fishing. Even the infamous northern cod stocks of Newfoundland, Canada - the 'poster fish' for stock collapse last century, and a region where I have personal experience - are now showing signs of recovery, and the fishery was re-opened in 2024.
We also need to consider the impacts of what we are doing on land and its impacts on the oceans and strive to reduce destructive practices and pollution.
In general, I am optimistic about the future of our oceans. Our global oceans are resilient and have shown their ability to bounce back. This includes increases in whale abundance since the end of exploitation, as well as the fish examples above.
In research carried out by NIWA, we have observed recoveries in marine habitats and seabed communities following devastating disturbance caused by the 2016 Kaikōura earthquake and Cyclone Gabrielle in 2023, as well as documenting resilience to experimental disturbance on the Chatham Rise.
Our oceans are resilient, but they are not inexhaustible or indestructible. We need to continue to balance exploitation and conservation through effective management so we can continue to enjoy the benefit of healthy oceans.
