Dead Zones

And another thing! The oceans of the planet are reportedly rapidly losing their ability to hold oxygen (https://www.theguardian.com/environment/2019/dec/07/oceans-losing-oxygen-at-unprecedented-rate-experts-warn). Water retains less oxygen as it becomes warmer and more salty, inevitable  consequences of climate change, so it is likely that more ocean dead zones will be created especially near the equator. Many fish populations (particularly rapid swimming species such as tuna and marlin) are likely to suffer.