Shortnose cisco (Coregonus reighardi) COSEWIC assessment and status report: chapter 7

Population Sizes and Trends

Although the deepwater cisco fishery (commonly known as the “chub fishery”) was very important in the Great Lakes, the catches were rarely identified to species (Lawrie and Rahrer 1973). Too few collections of shortnose cisco (recorded to species) have been documented over time in a standardized manner to evaluate population sizes and trends.

Webb and Todd (1995) documented the capture of a total of 324 individuals in Lake Huron in only 11 different years between 1919 and 1985. After the first record of shortnose cisco in 1919, based on a single specimen, it was not recorded in Lake Huron again until 1956 (n=106 individuals). It was subsequently recorded in 1966 (2), 1967 (3), 1973 (9), 1974 (2), 1975 (197), 1977 (1), 1980 (1), 1982 (1), 1985 (1). Despite extensive sampling of commercial catches and assessment surveys in Georgian Bay in 1992 and 1993 (Webb and Todd 1995), and targeted sampling of all Canadian sites in 2002 and 2003 (N.E. Mandrak, unpubl. data), no shortnose cisco were captured.  Another deepwater cisco, the shortjaw cisco (C. zenthicus), was recently (2002 and 2003) caught in Lake Huron after not being found since 1985 (N.E. Mandrak, unpubl. data).

Therefore, it is possible, but unlikely due to recent unsuccessful sampling, that the shortnose cisco might still be present in Lake Huron.

The National Biological Service (NBS) (currently part of the United States Geological Survey) conducted a Lake Michigan fisheries assessment program intermittently from 1951 to 1955, and continuously from 1960 to the present (Webb and Todd 1995). In the 1950s, 2,446 shortnose cisco individuals were captured. In 1960 and 1961, 1,107 individuals were captured. Between 1962 and 1967, no more than 10 individuals were captured per year, and only a single individual per year (none in 1971 and 1973) were caught between 1968 and 1982, the last year that shortnose cisco was recorded in Lake Michigan.

Limited survey data exist for the shortnose cisco in Lake Ontario (Webb and Todd 1995). Shortnose cisco (2 individuals) was last collected in Lake Ontario in 1964. Subsequent surveys by the Canadian Department of Fisheries and Oceans (2002, western basin only; N.E. Mandrak, unpubl. data) and NBS (Webb and Todd 1995) failed to collect any specimens.

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