Here is a story of the survival of the fittest. It seems it is caused by global warming or some other confounding factor. A recent publication by Kang et al. in “Environmental Biology of Fishes” tells a curious – potentially scary – case of things to come.
The team noticed a sudden spike in a particular variety of fish off the coast of southeast China. This weirdly named fish, the Bombay Duck, has had a ten-fold population growth in the last decade. Bombay Duck (Harpadon nehereus) is fish that can survive a low Oxygen environment due to a high (about 90%) water content in its tissues.
So scientists postulate that as the water temperature rises, thanks to global warming, the dissolved oxygen levels in the water drop, and makes the lives of the indigenous fish species in danger, leaving only those species that can thrive under these conditions to multiply in numbers. So a fish that did not exist in the national statistics as an independent species until recently suddenly becomes a dominant variety.
Increase of a hypoxia-tolerant fish: Environmental Biology of Fishes