Rainbow Smelt
(Osmerus mordax)


The rainbow smelt is a predatory fish. That means it eats other fish. You will find it in the north Atlantic coastal regions of North America and some lakes in the Ottawa Valley in the St. Lawrence River watershed. It was put in Michigan in the early 1900s by humans. This led to established rainbow smelt populations in lakes Erie, Michigan, Huron and Superior.

Humans put eggs in the Crystal Lake in 1912 to boost fish populations. You will find rainbow smelt through the Atlantic between New Jersey and Labrador to Arctic drainages, and the Pacific drainages all the way to Vancouver Island.

Effects on people

Rainbow smelt eat the baby fish of other species. This hurts the environment because it kills the babies making less of a species. When the rainbow smelt is eaten by other fish, contaminants happen. This is bad for humans because it disrupts the food chain.

People catch rainbow smelt for food and also recreationally. You can make them into animal feed, or prepare them for humans to eat. To fish for rainbow smelt, you would use a gill net. This is popular in Chicago.

Effects on ecosystem

Rainbow smelt overeat. This makes it so the other species can't eat as much. This has a negative effect on the ecosystem of water. Zooplankton are eaten by other fish. The rainbow smelt’s eating habits disrupt food webs. This leads to less zooplankton. Rainbow smelt eat the young of other species, then they are eaten by other adult fish. This results in higher concentrations of impurities in native fish. This can create a risk to humans.

Reasons for success

Rainbow smelt have improved fish populations overall. There are a lot of them and they are very small. They can be a food source for other fish. They also multiply quickly.

Smelt has healthy nutrients, and is low in mercury. There are many health benefits in smelt. People serve them baked, broiled or lightly fried.

Issues for the future

Rainbow smelt's biggest issue for the future is the destruction of ecosystems. This is primarily due to their overeating. They can destroy ecosystems if left unchecked. For this reason, you are never allowed to transport live rainbow smelt.

Ways to control the spread

There are many restrictions around rainbow smelt. While you can use rainbow smelt as bait, you can not transport live rainbow smelt. You also can not transport their eggs. If you are cleaning rainbow smelt, you can not dump entrails into a lake or river. It is very easy for fertilized rainbow smelt eggs to flourish in new waters.