|Image from Fishbase|
This is the Mekong Giant Catfish (Pangasianodon gigas), whose upper size limit is nine feet and 660 pounds, making it the world’s largest freshwater fish. They inhabit the Mekong River, the eleventh longest river in the world, which stretches through China, Thailand, Laos, Burma, Cambodia, and Vietnam. While the young have the whiskers that give catfish their name, those are lost as they age. I can’t seem to find a maximum age for these, but they can get quite old, considering the generation time is listed as 14 years.
The Giant Catfish is a grazer, eating the aquatic vegetation growing on the bottom of the river, though this source states that they’ll take “other food [read: meat] in captivity.” During the course of their lives, these massive fish will migrate up and down the river, from upstream breeding sites to downstream feeding sites.
As there is a lot of meat on a 600-pound catfish, it came to no surprise to me that one of the major causes of their decline is overfishing; even though that has mostly stopped, they’re still getting over it. Despite this, the Mekong Giant Catfish was moved from Endangered to Critically Endangered in 2003. The IUCN cites habitat loss and degradation—that is, damming and pollution—as the major causes.
Not all hope is lost. In an interview with National Geographic, one of the researchers says that there’s still a chance that these giants can make a comeback. They’ve been working on artificial spawning since 1985, and captive breeding since 2001. These, along with better pollution regulations, could bring the Mekong Giant Catfish back from the brink.
1I just wrote a ten-page paper on genitalia evolution. Look up the Argentine Lake Duck (Oxyura vittata), if you dare. Or, for that matter, Echidna reproduction.