Rainbow Smelt  (Osmerus Mordax)

DESCRIPTION

Rainbow Smelt is one of many common names given to the fish species Osmerus mordax. Some other common names include frostfish, American smelt, freshwater smelt, ice fish, lee fish, and smelt. Rainbow Smelt have an average adult body size of 7 to 9 inches, and weigh around 3 ounces. These fish have very slender bodies, and prefer dark cool waters. When viewed underwater they appear primarily silver with light green backs, and have an abundance of pink purple, and blue along their incomplete lateral line. The belly of this fish is white. Rainbow Smelt have a long pointed snout, a mouth full of teeth, an adipose fin, and a deeply forked caudal (tail) fin. Smelt feed primarily on crustaceans and small fish.  Smelt are an anadromous fish with a few land locked lake populations. An interesting fact about Rainbow Smelt is that they smell exactly like cucumbers when freshly caught. 

IMPACTS

Decreased Populations of Large Sport Fish
Rainbow Smelt were originally introduced to inland lakes as a baitfish for the more sought after sport fish such as Salmon Trout, and Walleye. However, this planned prey food source has ended up becoming a predator as well. Smelt have actually damaged the large sport fish populations in two ways. First, the adult smelt actually prey on the young sport fish. This added source of predation has decreased the abundance of sport fish in many ecosystems. The other negative effect of Smelt is that that as young of year fish the smelt directly compete with the young sport fish for the limited supply of zooplankton.

Economic Benefits and Downfalls
When the Rainbow Smelt populations began to explode in inland lakes the numbers of many recreational sport fish began to decline. For those who sought these prized sport fish this was a terrible outcome when the original reason for transporting smelt in was to increase the population levels of the desired fish. However, a economic benefit did arise from the situation. As the populations of Rainbow Smelt continued to increase, the numbers reached a high enough level to make commercial fishing for Smelt profitable. This along with an increased popularity of recreational fishing for smelt has helped to control their numbers. Recreational fishing can prove very effective either as winter time ice fishing, or more commonly during the spawning season when hundreds of thousands of Rainbow Smelt rush up lake tributaries to spawn. During these spawns many people will gather around streams with huge seines to pull in hundreds of the tasty fish.

Effects on the Ecosystem 
Rainbow Smelt populations that are found in inland lakes can have negative effects on the lake community. The smelt concentrates PCBs in its fatty tissue, and magnifies it through the food chain. High mercury levels also accumulate in the top food chain predators.  

(Source from: 1. Lakehead University Faculty of Forestry and the Forest Environment, http://www.borealforest.org/fish/smelt.htm; 2. Redpath Museum (Jake Vander Zanden), http://www.redpath-museum.mcgill.ca/Qbp/fish/specpages/rainbowsmelt.htm; 3. Wisconsin Natural Resources Magazine,  http://www.wnrmag.com/supps/2001/jun01/tales.htm#smelt)

ORIGIN

Rainbow Smelt were originally a fish of Eastern and Western North America, with most of the population occurring on the East coast between Labrador and New Jersey. On the Western coast of North America, Rainbow Smelt can be found as far south as Vancouver, and into the Alaskan Arctic Ocean to the North. Smelt occupy all North Atlantic waters and their tributaries.  Most of the species originally lived in the marine environments near the coast, but many landlocked lakes near the east coast had successful Smelt populations. Around 1900 some Rainbow Smelt from a freshwater lake in Maine were purposefully transported to Crystal Lake in Michigan to provide a food source for salmon and other large fish. Many other intentional transports similar to the one at Crystal Lake occurred as well. Although undocumented, it is also highly likely that fishermen furthered the spread, or perhaps even started, the spread of Rainbow Smelt to different lakes by unintentionally dumping leftover bait (Smelt) in northern lake waters. Once Rainbow Smelt were introduced into one lake they could quickly spread to other lakes through tributaries during spawning. By 1930 Rainbow Smelt populations had spread to all of the Great lakes. Today Smelt exist in a large number of northern lakes across the United States. Smelt are also still found in all of the Great Lakes with Lake Erie supporting the largest population. 

Source from: 1. Redpath Museum (Jake Vander Zanden), http://www.redpath-museum.mcgill.ca/Qbp/fish/specpages/rainbowsmelt.htm; 2. How tiny smelt wage war on walleyes, Wisconsin Natural Resources Magazine, http://www.wnrmag.com/supps/2001/jun01/tales.htm; 3. Wisconsin Natural Resources Magazine,  http://www.wnrmag.com/supps/2001/jun01/tales.htm#smelt; 4. Nova Scotia Department of Agriculture and Fisheries, http://www.gov.ns.ca/nsaf/Sportfishing/species/smel.htm; 5. A/F Protein Inc, http://www.afprotein.com/smelt.htm. 

Current techniques can't eliminate smelt from lake communities without harming the rest of the lake population. For now the best way to deal with the problem is to reduce it through educational programming. The further spread of Rainbow Smelt and other exotics can be reduced, if not eliminated through aggressive educational programs that inform citizens of the hazards and negative effects that many exotics can have on an ecosystem. Tough state and federal laws that restrict the live transportation of exotics can also help in reducing their spread.

(Source: 1. Wisconsin Natural Resources Magazine,  http://www.wnrmag.com/supps/2001/jun01/tales.htm#smelt)

Smelt Family: New York Sportfishing and Aquatic Resources Education Program (SAREP) 
    http://www.sarep.cornell.edu/Sarep/fish/Osmeridae/osmeridae.html
This web site contains a nice picture of a smelt as well as some general characteristics of the species

Rainbow Smelt: Nova Scotia Department of Agriculture and Fisheries
    http://www.gov.ns.ca/nsaf/Sportfishing/species/smel.htm
A very detailed description of the rainbow smelt, and some useful links. .

Rainbow Smelt: Boundary Waters Canoe Area Wilderness (BWCAW) of northern Minnesota
    http://www.rook.org/earl/bwca/nature/fish/osmerus.html
A complete description of smelt, as well as biological processes, and historical past of the fish species.

How tiny smelt wage war on walleyes: Wisconsin Natural Resources Magazine
    http://www.wnrmag.com/supps/2001/jun01/tales.htm#smelt
This web site discusses Rainbow smelt as an exotic species, and briefly explains the adverse effects of the species in lakes where it has been introduced.

Rainbow Smelt: A/F Protein, Inc
    http://www.afprotein.com/smelt.htm
A general description of the smelt, including distribution around Canada and the Great Lakes, habitat, and food. 

Rainbow Smelt: Redpath Museum
    http://www.redpath-museum.mcgill.ca/Qbp/fish/specpages/rainbowsmelt.htm
Good information about distribution of the smelt, with a distribution map for Quebec.

Rainbow Smelt: Wisconsin Sea Grant
    http://www.seagrant.wisc.edu/greatlakesfish/rainbowsmelt.html
A brief description of the smelt and its origin and distribution.

Osmerus mordax (Rainbow Smelt): USGS NAS (Author: Pam Fuller)
    http://nas.er.usgs.gov/fishes/accounts/osmerida/os_morda.html
A complete description of smelt as well as native range, occurrence, means of introduction, status, impact, and references. 

Rainbow Smelt: Captain Dave’s Fishing & Boating Pages
    http://www.cptdave.com/rainbow-smelt.html
The site explains general information regarding the smelt, reproduction, habitat, food, angling tips, fishing season, handling, and cooking

 Do you know your catch? Rainbow Smelt
    http://www.state.me.us/dmr/recreational/fishes/smeltrainbow.htm
This web page has brief information about the smelt, including common name, description, and where found.

Integrated Fisheries Management Plan: RAINBOW SMELT, PRINCE EDWARD ISLAND (Canada).

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