Detection of Natural Hybridization between Pink Salmon (Oncorhynchus gorbuscha) and Chinook Salmon (Oncorhynchus tshawytscha) in the Laurentian Great Lakes Using Meristic, Morphological, and Color Evidence

In August 1992, a Pacific salmon resembling a pink salmon was caught in Michigan's St. Marys River. The specimen, which weighed 6.38 kg and measured 792.5 mm total length, was submitted to the International Gamefish Association (IGFA) as a world record pink salmon. The IGFA requested confirmation of the specimen's identification from G. Smith, Curator of Fishes at the University of Michigan's Museum of Zoology. Based on skeletal characters and color patterns, the specimen was identified as a hybrid between pink salmon (Oncorhynchus gorbuscha) and chinook salmon (O. tshawytscha; G. Smith, pers. comm.). Subsequent analysis of one nuclear DNA locus supported this conclusion (B. Shields, pers. comm.). Here, I report on meristic, morphological, and coloration patterns of suspected hybrids between pink and chinook salmon from the St. Marys River.