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Psephurus and Polydon

Submitted by mtracy on Sat, 10/06/2018 - 00:08

Psephurus, or chinese paddlefish, is a large cartilaginous fish of the order acipenserifomres. These live in freshwater rivers, such as the Yangtze and its associated lakes. Historically, Psephurus could reach 7 meters in length. Unfortunately over time, these large fish were fished nearly out of existence. Additionally it was a major victim of the construction of the three gorges dam, as the migration that takens place between mating seasons could no longer take place. The last known specimen was killed illegally in 2007 and was only 3.6m long. No other Psephurus have been identified since.

The North American cousin to Psephurus is known as Polydon. Polydon lives in large freshwater rives as well, such as the Misissippi and Ohio rivers. Its long snout is covered with sensitive electrosensors, which can be used to detect swarms of plankton. The fish will swim forcefully through the water, injesting the plankton which are filtered through the gill rakes. Plankton are diverted to the fish's stomach, while water exits through the gill slits. Unlike Psesphurus, Polydon does not get as large; only about 2 meters in length. Unfortunately, much like Psesphurus, Polydon is a victim of overfishing, and due to dams can only be sustained by captive breeding.

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