Most of the Bucketeers have already heard the tale of Matching Mole and I and our kayaking encounter with the Giant Flying Killer Goldfish of Death. :) But here's the story behind these fish.
The Daily Bucket is a regular series from the Backyard Science group. Here we talk about Mother Nature in all her glory, especially the parts that live nearby. So let us know (as close as you are comfortable) where you are and what's going on around you. What's the weather like? Seen any interesting plants, bugs or critters? Are there birds at your feeders? Deer, foxes or peahens in your yard? Seen any cool rocks or geological features? Post your observations and notes here. And photos. We like lots of photos. :)
Carp are, biologically, just giant minnows. Belonging to the Cyprinid family of fishes, they are widely distributed around the world. Their best-known member is Carassius auratus, the plain ole ordinary petshop Goldfish, which is native to eastern Asia, and its close relative Carassius carpio, the Koi, also known in the wild as the Common Carp. Other Asian carp species include the Grass Carp (Ctenopharyngodon idella) and the Silver Carp (Hypophthalmichthys molitrix).
In their native areas, the Asian carp species are widely-used as food fish (though they have a lot of bones, and wild ones have a reputation for a "muddy" taste). In particular, the Silver Carp is widely used in aquaculture, and has been imported to at least 88 different countries to be raised as a food fish. So it was probably inevitable that escapees would become established. Although the wild population in China is now considered a threatened species, captive and introduced Silver Carp are common all over the world. They prefer quiet stagnant water, where they can tolerate low oxygen levels that would kill most other fish.
Asian Carp species, including both Silver and Grass Carp, were imported into the United States in the 1960's. Escapees in Arkansas established themselves in the Mississippi River after a flood, and spread outwards. Since the fish can reproduce quickly and eat a lot, they can out-compete native fishes and crowd them out. By the 1990's, Asian Carp had been established in 23 states. Federal and state wildlife officials, realizing the tremendous ecological damage that would happen if the invasives reached the Great Lakes, constructed a series of electric "fish fences" to keep them out.
In Florida, the Grass Carp was introduced intentionally. While the Silver Carp is a filter feeder that makes its living by straining phytoplankton from the water, Grass Carp eat aquatic plants. So, back in the 1990's, Florida wildlife officials decided to utilize the species as a biological weapon against the many varieties of invasive non-native water plants (including Water Lettuce, Hydrilla, and Water Hyacinth) that have become ecological threats in the state. To insure that the Carp themselves would not become just another invasive species, fish eggs are chemically treated to form a "triploid" breed, with three copies of each chromosome instead of the normal two. This makes the fish sterile and incapable of breeding. The sterile Carp were introduced into lakes and rivers all over Florida. (The fish will still mate and spawn as usual, but the resulting eggs are infertile and don't hatch.) Since the Carp were intentionally released by the state as a biological control on invasive plants, it is illegal to catch or harm them.
So, why did the Giant Flying Goldfish try to kill Matching Mole and me?
Well, they were just trying to protect themselves. In the wild, the fish are prey for a number of predators, and their natural defense, when they are frightened by something, is to leap wildly out of the water to escape the threat. Although Asian carp species can reach three feet in length and weigh over 50 pounds, their powerful muscles can push them as much as ten feet out of the water. And since the fish tend to hang around in schools, when a group of them is startled by a boater or kayaker, there may be several dozen of them leaping in all random directions. It is a veritable barrage of fish.
It's a serious matter. Even a 1-2 foot Carp is big enough to cause some intense damage if it hits a boater or swimmer. There have been instances of people receiving broken jaws or ribs from flying Carp impacts, and one reported death.
Fortunately, Florida officials tightly control the number of Carp that they release. And so far there are no populations of viable invasive Carp species that have made their way to Florida. At least not yet.
And now it’s your turn—what’s jumping around in your neck of the woods? :)