Bering cisco (Coregonus laurettae) COSEWIC assessment and status report: chapter 9

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Population Sizes and Trends

Alaskan fisheries biologists, who work on lower portions of the Yukon River, believe that Bering cisco spawners far outnumber any other salmonid species during the late summer and fall. Their scarcity in Canadian waters of the Yukon River is probably because the majority of spawning activity is farther downstream in Alaska. The fact that they continue to be occasionally captured in the Canadian portion of the Yukon River suggests some stability in their pattern of movement.

The number of fish entering Canadian waters is unknown. However, Aboriginal Traditional Knowledge (ATK) indicates that the species is known to elders in Dawson City and has a historical presence (Nagano, pers comm., 2004). Numbers counted at the fishwheels since the 1980s have been low (< 100/yr). However, counting is not consistent, and technicians are not trained to recognize the species, which may be easily confused with other sympatric coregonids.

There has been very little research, assessment or management effort specific to Bering cisco throughout its range. Information that is available is more of a presence or absence nature and ancillary to the study of other salmonid species. Alaskan cisco harvest statistics are inconsistent between regions. Specific catch trends are difficult to establish as catches of Bering cisco are combined with other coregonines (Buklis 2002). 

In the Yukon Territory, a hundred or less continue to be encountered each year in fishwheels near Dawson City, although not all fish passing the wheels are sampled. Until recently, record keeping has only been concerned with salmon migrations; for the most part catches of other species were not recorded. Since 1999 some effort has been made to capture information on species other than salmon, but until now this has been sporadic and often the technicians cannot differentiate Bering cisco from other sympatric whitefishes, although it is assumed that some spawn in Canadian waters (Milligan, pers. comm., 2003). Recent captures of unidentified adult ciscos in fishwheels upstream of Dawson are presented in Table1; however, one must bear in mind that this is not a record of all ciscos that may have passed through the wheels in those years, only those that were recorded.  Based on the time of spawning, it would appear that least cisco would be more likely captured in the summer months of June, July and August and Bering cisco during September and October.

Source: Pat Milligan, DFO Whitehorse.

Since 2002 the Yukon Salmon Commission has been using rotary screw traps (Figure 5) to capture juvenile fish in the Yukon River in the vicinity of Dawson, and the author has assisted in the development of criteria for the identification of juveniles. Using these criteria 379 juveniles were identified in 2004 (Table 2), which suggests that the species is reproducing in Canadian waters. The reader is cautioned to note that these are preliminary findings that have yet to be confirmed by genetic analysis, which is in progress.

Figure 5: Photograph of the Rotary Screw Trap on Site in the Yukon River Near Dawson City

Courtesy Jim Duncan, Yukon Salmon Commission.

Data courtesy Jim Duncan, Yukon Salmon Commission.