Dead Zones are areas in the oceans that have very little oxygen. They don’t have enough oxygen to support most marine life. We’ve known about them for a long time, but now the number of them are increasing rapidly. This threatens populations of large fish, including tuna.
This is tied in with climate change, because warmer water can’t hold as much oxygen as colder water. Over time, this will have profound effects on many marine populations.
Scientists have recently found that there is much more biodiversity in the oceans than we thought. Especially in the so called oceanic deserts.
The mesopelagic is the region in the ocean that is between 100 m and 1000 m deep; this is a huge region of water. We’ve thought for a long time that this area doesn’t have much fish. Now we know that about 95% of the ocean’s fish live in this zone. They have larger eyes to be able to see where there isn’t much sunlight. They also can detect and avoid fishing nets.
While the article written for phys.org says that the fish can avoid nets from 5 m away, the paper written by the original author says that the fish avoid nets from much further out, 100 m away, and take hours to return to the area. This is one of the main reasons that we haven’t known much about these fish before.