The Nonindigenous Occurrences section of the NAS species profiles has a new structure. The section is now dynamically updated from the NAS database to ensure that it contains the most current and accurate information. Occurrences are summarized in Table 1, alphabetically by state, with years of earliest and most recent observations, and the tally and names of drainages where the species was observed. The table contains hyperlinks to collections tables of specimens based on the states, years, and drainages selected. References to specimens that were not obtained through sighting reports and personal communications are found through the hyperlink in the Table 1 caption or through the individual specimens linked in the collections tables.

Salvelinus fontinalis x namaycush
Salvelinus fontinalis x namaycush
Native Hybrid
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Salvelinus fontinalis x namaycush

Common name: splake

Native Range:
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Alaska auto-generated map
Hawaii auto-generated map
Caribbean auto-generated map
Puerto Rico &
Virgin Islands
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Guam Saipan
Hydrologic Unit Codes (HUCs) Explained
Interactive maps: Point Distribution Maps

Nonindigenous Occurrences:

Table 1. States with nonindigenous occurrences, the earliest and latest observations in each state, and the tally and names of HUCs with observations†. Names and dates are hyperlinked to their relevant specimen records. The list of references for all nonindigenous occurrences of Salvelinus fontinalis x namaycush are found here.

StateYear of earliest observationYear of last observationTotal HUCs with observations†HUCs with observations†
California195519551Upper Yuba
Colorado197620097Lower Gunnison; South Platte; South Platte Headwaters; St. Vrain; Upper Arkansas; Upper Arkansas-Lake Meredith; Upper Gunnison
Idaho1990200716American Falls; Boise-Mores; Clearwater; Little Salmon; Lower Bear-Malad; Lower Kootenai; North Fork Payette; Pend Oreille Lake; Spokane; Teton; Upper Henrys; Upper Snake; Upper Snake-Rock; Upper Spokane; Weiser; Willow
Maine1958201118Allagash; Aroostook; East Branch Penobscot; Headwaters Saint John River; Lower Androscoggin; Lower Kennebec; Lower Penobscot; Maine Coastal; Meduxnekeag; Passamaquoddy Bay-Bay of Fundy; Piscataquis; Presumpscot; Saco; St. Croix; St. George-Sheepscot; Upper Androscoggin; Upper Kennebec; West Branch Penobscot
Michigan197719993Betsie-Platte; Betsy-Chocolay; Lake Huron
Minnesota1974201111Baptism-Brule; Beaver-Lester; Big Fork; Cloquet; Elk-Nokasippi; Little Fork; Mississippi Headwaters; Platte-Spunk; Prairie-Willow; Rainy Headwaters; St. Louis
New Hampshire198019882Middle Connecticut; Saco
New York197919973Ausable River; Mohawk; Upper Hudson
South Dakota198519942Missouri Region; Rapid
Utah199220003Duchesne; Fremont; San Rafael
Wisconsin1958201310Beartrap-Nemadji; Flambeau; Lake Michigan; Lake Superior; Manitowoc-Sheboygan; Oconto; Peshtigo; Upper Fox; Upper Wisconsin; Wolf
Wyoming199420016Big Horn; Little Wind; North Platte; Popo Agie; Upper North Platte; Upper Wind

Table last updated 5/25/2018

† Populations may not be currently present.

Means of Introduction: Although uncommon in nature, some jurisdictions artificially propagate splake in substantial numbers for planting into brook trout or lake trout habitats. An example would be in Ontario, where both F1 splake and a fish known as the lake trout backcross have been planted for several years (Kerr, 2000).

Status: Failed in California (Dill and Cordone 1997). Established in several watershed in Idaho (Idaho Department of Fish and Game 2007). Stocked in multiple counties in Minnesota (Minnesota Department of Natural Resources 2012).

Impact of Introduction:  The backcross is the result of an F1 splake male being crossed with a female lake trout (i.e., 75% lake trout and 25% brook trout).   Splake are relatively unusual among hybrids in that they are fertile.

The following are impacts listed by Kerr (2002) in his literature review:

Splake are highly piscivorous and are known to predate several species of fish and their eggs (Berst et al. 1981, Kerr and Grant 2000). In East Lake, Ontario, the introduction of F1 splake reduced the density of a stunted yellow perch population (Rumsey and Lamarre 1994). In at least one instance (Satterfield and Koupal 1995) splake have been used as a predator to reduce high density, stunted brook trout stocks.

There is likely some level of competition for food with other species of fish. Potter (1995) suggested that there may be some competition with smallmouth bass for crayfish. In addition, splake are believed to compete for food with rainbow trout during the spring and fall (Leik 1959a, Burkhard 1962).

Splake can utilize nearshore areas for three seasons of the year but are forced to deeper cooler waters, often in the thermocline, during summer months. There is some evidence that, where the species coexist, splake may compete with brook trout for spawning habitat (Hansen 1972).

The F1 splake is a fertile hybrid and there is the potential for hybridization with either parent species in waters where they coexist. Genetic impacts may be of particular concern with brook trout (Fisher 1986, Fuller et al. 1999).

Remarks: Although they are fertile, back-crossing in nature is behaviorally problematic — very few natural progeny are produced by introduced splake populations.  The splake grow more quickly than do wild-strain brook trout and become piscivorous at a younger age and, hence, are more tolerant of competitors than are brook trout.

References: (click for full references)

BERST, A. H., A. R. EMERY and G. R. SPANGLER. 1981. Reproductive behavior of hybrid char (Salvelinus fontinalis x Salvelinus namaycush). Canadian Journal of Fisheries and Aquatic Sciences 38 : 432-440.

BURKHARD, W. T. 1962. A study of the splake trout in Parvin Lake, Colorado. M. Sc. Thesis, Colorado State University, Fort Collins, Colorado.

Dill, W.A., and A.J. Cordone. 1997. History and status of introduced fishes in California, 1871-1996. California Department of Fish and Game Fish Bulletin 178.

Durkin, Pat. 2005. Brookie backers protest splake stocking. Green Bay Press Gazette, August 10:1-2.

FISHER, J. R. 1986. Stocking programs. p. 42-46 In Redrock Lake: A review of the fisheries and management history. Algonquin Fisheries Assessment Unit, Ontario Ministry of Natural Resources, Whitney, Ontario.

FULLER, P. L., L. G. NICO and J. D. WILLIAMS. 1999. Nonindigenous fishes introduced to inland waters of the United States. American Fisheries Society Special Publication 27, Bethesda, Maryland. 613 p.

HANSEN, D. W. M. 1972. Reproductive interactions between the brook trout and splake of Redrock Lake. M. Sc. Thesis, University of Toronto.

Idaho Department of Fish and Game. 2007. Fisheries Management Plan 2007 – 2012. Boise, ID.

Idaho Department of Fish and Game. 2012. Idaho Department of Fish and Game fish stocking database, 1967-2012. Boise, ID. http://fishandgame.idaho.gov/public/fish/stocking/

Kerr, S. J. 2000. F1 Splake: An annotated bibliography and literature review. Fish and Wildlife Branch, Ontario Ministry of Natural Resources, Peterborough, Ontario. 79 p. + appendices.  http://www.mnr.gov.on.ca/stdprodconsume/groups/lr/@mnr/@letsfish/documents/document/226919.pdf

KERR, S. J. and R. E. GRANT. 2000. Potential interactions and impacts of splake stocking. p. 247 In Ecological Impacts of Fish Introductions: Evaluating the Risk. Fish and Wildlife Branch, Ontario Ministry of Natural Resources, Peterborough, Ontario. 473 p.

LEIK, T. H. 1959a. An evaluation of the splake trout – Ecology and life history of the splake trout. Colorado Cooperative Fishery Research Unit, Quarterly Report, Volume 5, Colorado A&M College. Fort Collins, Colorado. 25 p.

Minnesota Department of Natural Resources 2012. Minnesota LakeFinder - stocking reports. http://www.dnr.state.mn.us/lakefind/index.html

POTTER, B. A. 1995. F1 Splake-bass interactions. File memo, Aquatic Ecosystems Branch, Ontario Ministry of Natural Resources, Toronto, Ontario. 2 p.

RUMSEY, C. and T. LAMARRE. 1994. A preliminary report on the effects of F1 splake plantings on a stunted yellow perch population in a small Precambrian Shield lake. Unpublished report, Sir Sandford Fleming College, Lindsay, Ontario. 7 p.

Rasmussen, J.L. 1998. Aquatic nuisance species of the Mississippi River basin. 60th Midwest Fish and Wildlife Conference, Aquatic Nuisance Species Symposium, Dec. 7, 1998, Cincinnati, OH.

SATTERFIELD, J. R., Jr. and K. D. KOUPAL. 1994. Splake as a control agent for brook trout in small impoundments. p. 431-436 In H. L. Schramm and R. G. Piper [eds.] Uses and Effects of Cultured Fishes in Aquatic Ecosystems. American Fisheries Society Symposium 15.

Tilmant, J.T. 1999. Management of nonindigenous aquatic fish in the U.S. National Park System. National Park Service. 50 pp.

Other Resources:
Fact Sheet for Salvelinus fontinalis - USGS Nonindigenous Aquatic Species Database

Fact Sheet for Salvelinus namaycush - USGS Nonindigenous Aquatic Species Database

Author: Matt Neilson, and Pam Fuller

Revision Date: 5/20/2013

Peer Review Date: 4/1/2016

Citation Information:
Matt Neilson, and Pam Fuller, 2018, Salvelinus fontinalis x namaycush: U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, https://nas.er.usgs.gov/queries/FactSheet.aspx?SpeciesID=940, Revision Date: 5/20/2013, Peer Review Date: 4/1/2016, Access Date: 12/11/2018

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.

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Page Contact Information: Pam Fuller - NAS Program (pfuller@usgs.gov)
Page Last Modified: Wednesday, October 24, 2018


The data represented on this site vary in accuracy, scale, completeness, extent of coverage and origin. It is the user's responsibility to use these data consistent with their intended purpose and within stated limitations. We highly recommend reviewing metadata files prior to interpreting these data.

Citation information: U.S. Geological Survey. [2018]. Nonindigenous Aquatic Species Database. Gainesville, Florida. Accessed [12/11/2018].

Contact us if you are using data from this site for a publication to make sure the data are being used appropriately and for potential co-authorship if warranted. For queries involving fish, please contact Pam Fuller. For queries involving invertebrates, contact Amy Benson.