Tiger trout
Scientific classificationEdit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Salmoniformes
Family: Salmonidae
Subfamily: Salmoninae
Hybrid: Salmo trutta × Salvelinus fontinalis

The tiger trout (Salmo trutta × Salvelinus fontinalis) is a sterile, intergeneric hybrid of the brown trout (Salmo trutta) and the brook trout (Salvelinus fontinalis). Pronounced vermiculations in the fish's patterning gave rise to its name, evoking the stripes of a tiger. Tiger trout are a rare anomaly in the wild, as the parent species are relatively unrelated, being members of different genera and possessing mismatched numbers of chromosomes.[1][2][3] However, specialized hatchery rearing techniques are able to produce tiger trout reliably enough to meet the demands of stocking programs.[4][5]

Natural occurrence

Prior to the 19th century, naturally occurring tiger trout were an impossibility, as the native range of brown trout in Eurasia and brook trout in North America do not overlap and the species could therefore never have encountered one another in the wild.[3] When the widespread stocking of non-native gamefish began in the 1800s, brown trout and brook trout began establishing wild populations alongside each other in some places and the opportunity for hybridization in the wild arose.[6] Instances of stream-born tiger trout were recorded in the United States at least as early as 1944 and, despite being exceptionally rare, they've been documented numerous times since during the 20th and 21st centuries.[3]

Tiger trout result exclusively from the fertilization of brown trout eggs with brook trout milt, as brook trout eggs are generally too small to be successfully fertilized by brown trout milt.[1] Tigers are known as intergeneric hybrids as the two parent species share only a relatively distant relationship, belonging to different genera within the Salmon family. In fact, brook trout and brown trout have non-matching numbers of chromosomes, with the former possessing 84 and the latter 80.[7] Consequently, even in cases in which brown trout eggs are fertilized by brook trout in the wild, most of these eggs develop improperly and fail to yield any young.[1]

Hatchery rearing

Tiger trout can be produced reliably in hatcheries and they've been incorporated into stocking programs in the United States at least as early as the 1960s.[8] Hatchery productivity is enhanced by heat shocking the fertilized hybrid eggs, causing the creation of an extra set of chromosomes which increases survival rates from 5% to 85%.[9] Tiger trout have been reported to grow faster than natural species,[10] though this assessment is not universal.[11] They are also known to be highly piscivorous and are consequently a useful control against rough fish populations.[7] This, along with their desirability as novel gamefish, means tigers have continued to be popular with many fish stocking programs. US states with tiger trout stocking programs include Arizona,[2] Arkansas,[12] Colorado,[13] Connecticut,[14] Idaho,[15] Washington,[16] West Virginia,[17] Wyoming,[4] Utah, Virginia,[18] Oregon,[19] and Massachusetts.[20]

See also

References

  1. 1 2 3 "Tiger trout — myth or fact?/Biological bits". The Daily Mining Gazette. The Mining Gazette. Retrieved 24 June 2022.
  2. 1 2 "Tiger Trout". Arizona Game and Fish Department. Arizona Game and Fish Department. Retrieved 24 June 2022.
  3. 1 2 3 "Tiger Trout (Salmo trutta × Salvelinus fontinalis) - Species Profile". NAS - Nonindigenous Aquatic Species. U.S. Geological Survey. Retrieved 24 June 2022.
  4. 1 2 "Making tiger trout". Wyoming Game & Fish Department. Wyoming Game & Fish Department. Retrieved 24 June 2022.
  5. ↑ Altman, Jim (24 March 2022). "Trout Season goes year-round and DEEP is stocking up". FOX 61. FOX 61. Retrieved 24 June 2022.
  6. ↑ Pister, Edwin P. (June 2001). "Wilderness Fish Stocking: History and Perspective". Ecosystems. 4 (4): 279. Retrieved 9 July 2022.
  7. 1 2 Windham, Rick (27 September 2018). "What is a tiger trout?". AP NEWS. Retrieved 11 July 2022.
  8. ↑ "Tiger trout are stocked". The Daily Record (Long Branch, New Jersey). April 26, 1963.
  9. ↑ Thousands of tigers released in Utah (trout that is!) Utah Division of Wildlife Resources, 24 May 2005. Retrieved 11 September 2006
  10. ↑ Watch out, Utah chubs: Tiger trout placed in Scofield Reservoir Utah Division of Wildlife Resources, 24 May 2005. Retrieved 11 September 2006
  11. ↑ Tiger Trout & Hybrids Archived 2006-08-28 at the Wayback Machine Pennsylvania Fish & Boat Commission. Retrieved 11 September 2006
  12. ↑ "State seeks big fish tales for tiger trout record". Arkansas Game and Fish Commission. Retrieved 2 November 2023.
  13. ↑ "Great reservoir fishing abounds in southwest Colorado". CO,US. Colorado Parks and Wildlife. Retrieved 13 January 2024.
  14. ↑ "Fish Stocking Report 2021" (PDF). CT.GOV. Connecticut Department of Energy & Environmental Protection. Retrieved 13 January 2024.
  15. ↑ "New state record tiger trout set in southeast | Idaho Fish and Game". idfg.idaho.gov. Idaho Fish and Game. 30 May 2023. Retrieved 13 January 2024.
  16. ↑ "Tiger trout". wdfw.wa.gov. Washington Department of Fish & Wildlife. Retrieved 13 January 2024.
  17. ↑ "WVDNR stocking trophy tiger trout in April and May". WVDNR.GOV. West Virginia Division of Natural Resources. 8 April 2021. Retrieved 13 January 2024.
  18. ↑ "Tiger Trout in Virginia". dwr.virginia.gov. Virginia Department of Wildlife Resources. Retrieved 16 January 2023.
  19. ↑ "Diamond Lake: Inaugural stocking of tiger trout". Oregon Department of Fish and Wildlife. Retrieved 19 July 2023.
  20. ↑ "MassWildlife Trout Stocking Program". www.mass.gov. Retrieved 11 July 2022.
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