Marine Biology

Why the Paddlefish is Endangered



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The paddlefish is a species that used to be abundant in both China and the midwestern United States. There are two subspecies of paddlefish, the American and Chinese paddlefish, and both are listed as endangered and quickly approaching extinction. If action is not taken soon, both of these subspecies of paddlefish may be extinct. Many factors have brought the paddlefish to near extinction, all of them the product of human intervention.

The American paddlefish lives in the freshwater Mississippi river and surrounding areas, and is closely related to the sturgeon. They can reach up to seven feet in length at maturity and, like many large fish, they mature very slowly. It is not uncommon for the paddlefish to attain sexual maturity at 7 to 8 years for males and over 10 years for females. This subspecies of paddlefish used to be abundant from the Great Lakes and could be found all the way down the length of the Mississippi, as well as throughout the midwest United States.

Recently, paddlefish were also discovered in the Danube river in Europe, though it is not entirely clear how they got there. They feed primarily on zooplankton. Currently there are no paddlefish in any of the Great Lakes because the invasion of zebra mussels has diminished the zooplankton to a point where it is impossible for the paddlefish to live there any longer. They can still be found in 22 states, and their status is listed as endangered in 11 of those. 

Probably the biggest factor that decimated the American paddlefish is overfishing. There is a huge market for caviar, and the paddlefish's roe is similar to that of a sturgeon. This makes it very valuable on the caviar market. In recent history there have been several large-scale slaughters of paddlefish in order to harvest their roe for sale. Unfortunately, it takes nearly a decade for a paddlefish to be sexually mature, which makes it difficult for the population to recover from such large scale killings. Adding to the problem is that this fish does not spawn every year, which makes it even more difficult for the population to sustain itself under such pressure. In the United States this fish is also a popular sport fish. Some states in its region have banned sport fishing in order to make more conservation efforts, but others have attempted to manage the fishing.

Another factor that is making it difficult for the American paddlefish to make a comeback is the creation of man-made dams in their habitat. In order to successfully spawn, this fish needs swift currents and a rocky bottom, or else their eggs will be washed away in the current and die. When humans create a dammed area they destroy this kind of habitat and further limit the places where this fish can spawn.

The second subspecies, the Chinese paddlefish, was once found throughout China but is now incredibly rare. It is thought to be similar to the American paddlefish in size and breeding patterns, but that is not certain. There are unconfirmed reports that the Chinese paddlefish can reach lengths of over 20 feet; however, given the scarcity of the fish, it would be impossible to determine if that is normal. The Chinese paddlefish has faced the same issues as its American cousin. The People's Republic of China has officially named this species critically endangered and it has been made illegal to fish for either juveniles or adults. There is suspicion in the scientific world that this subspecies may in fact be extinct. 

The last known sighting of a living specimen was in 2003. A scientific expedition took place between 2006 and 2008 that looked specifically for this fish, and none were found during that entire time period. In 2007, it was confirmed that the fish may still be around when a single specimen was caught illegally. It was transferred to a pen in the hopes it would survive, but it died shortly thereafter from injuries sustained during its capture. At this time this species is thought to have so few individuals that it is impossible for it to maintain a breeding population and likely will become extinct in the near future. There is a small hope that the Chinese paddlefish can be saved through private breeding or aquarium breeding programs, but success will not be determined for many years to come.

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ARTICLE SOURCES AND CITATIONS
  • InfoBoxCallToAction ActionArrowhttp://environment.nationalgeographic.com/environment/freshwater/chinese-paddlefish/
  • InfoBoxCallToAction ActionArrowhttp://www.thevlm.org/paddlefish.aspx
  • InfoBoxCallToAction ActionArrowhttp://wwf.panda.org/what_we_do/endangered_species/paddlefish/
  • InfoBoxCallToAction ActionArrowhttp://www.npwrc.usgs.gov/resource/wildlife/nddanger/species/polyspat.htm