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).
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.
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.