Data deficient or not assessed
Too little is known to judge. 43 fish on EveryFish so far.
Data Deficient is the IUCN Red List category for species that have been assessed but for which there is too little information to judge the risk of extinction. It is not a statement that a species is safe. Many fish fall here or have never been assessed at all, especially those of tropical rivers, the deep sea and poorly surveyed coasts. Some well-known fish are Data Deficient because their numbers are hard to count.
Too little known
The arapaima of the Amazon is listed as Data Deficient: it has been overfished in many areas but has recovered under community management in others, and it is hard to count across such a vast basin. The common sole of Europe, one of the most valuable flatfish, and the giant grouper of the Indo-Pacific are also listed as Data Deficient. Many small fish of India's rivers and wells, such as the blind catfish of Kerala's aquifers, are known from only a few specimens.
Not assessed
Of the more than 36,000 known fish species, many have never been assessed by the IUCN, and others have assessments more than ten years old. Species described recently, such as many cave fish and deep-sea fish, often have no assessment at all. EveryFish groups these under Data Deficient or not assessed. Scientists use surveys, environmental DNA and catch records to fill the gaps, and some Data Deficient fish turn out to be threatened once they are studied.
Famous data deficient or not assessed fish
Still to be written: Common sole, Bighead carp.
Further reading
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Photo credits on this page
The small pictures above come from Wikimedia Commons under free licences. Some are cropped to fit.
- Giant grouper: Ginkgo100, CC BY-SA 3.0, source
- Arapaima: This illustration was made by Citron You must credit this : Citron / C, CC BY-SA 3.0, source