While most fish cast their eggs and sperm in clouds and leave their young to develop by themselves, there are some fish (about 2 percent) who keep their fertilized eggs in their mouths. These fish are called “mouthbreeders”.
This is a parazen (Parazen pacificus), the first deep-sea fish known to mouthbrood.
Deep-sea fishes normally spawn externally, and their young migrate to more productive shallow waters before returning as adults to the food-scarce deep. But mouthbrooding is a comparatively costly investment. Some shallow water mouthbreeders eat with a mouth full of eggs, which is more difficult and costs more energy, and others abstain from eating entirely as the young develop, draining energy reserves.
In other words, this parazen has sacrificed a lot to protect its young, and according to Randy Singer, an ichthyologist who discovered the fish’s characteristics way back in 2015, this calls for “further investigation.”
More details about this story over at ScienceNews.
(Image Credit: R. Singer, J. Moore, E. Stanley, NOAA Okeanos Explorer)
finally the story can be told
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