. The Canadian field-naturalist. Figure 1. Deepwater Cisco, Coregonus johannae (from Todd 1980, by permission). Kernan, personal communication) also failed to produce any authenticated specimens of Corego- nus johannae from United States waters. Published information dealing specifically with Coregonus johannae populations in Lake Huron is lacking. Berst and Spangler (1972) state that the larger species of deepwater ciscos (which would include Coregonus johannae) had been selectively removed from Lake Huron by the 1940s as a result of Sea Lamprey predation and commercial fishing, as was the ca
. The Canadian field-naturalist. Figure 1. Deepwater Cisco, Coregonus johannae (from Todd 1980, by permission). Kernan, personal communication) also failed to produce any authenticated specimens of Corego- nus johannae from United States waters. Published information dealing specifically with Coregonus johannae populations in Lake Huron is lacking. Berst and Spangler (1972) state that the larger species of deepwater ciscos (which would include Coregonus johannae) had been selectively removed from Lake Huron by the 1940s as a result of Sea Lamprey predation and commercial fishing, as was the case in Lake Michigan. The last specimen recorded from Canadian waters of Lake Huron was in 1952 (ROM 19214). Coregonus johannae is now considered extinct in Canadian waters of Lake Huron (R. Payne, personal communication). Habitat Little is known of the habitat of Coregonus johannae. Capture data indicate the depth distribution of this species ranges between 29 and 143 m (Koelz 1929). Koelz also reported this. Figure 2. Former distribution of the Deepwater Cisco, Coregonus johannae: (1) Extinct — lakes Michigan and Huron (R. Payne, personal communication; Todd 1980). species was rarely caught at depths of less than 64 m, and maximum abundance occurred between 91 and 143 m. Todd (1980) reports a depth range of 50 to 160 m. General Biology Reproductive Capability: Information on repro- ductive characteristics of Coregonus johannae is scarce. Koelz (1929) reported that specimens smaller than 165 mm were not mature and that most specimens 195 mm in length were mature. Todd (1980) reports adult size from 250 to 300 mm standard length (SL). Breeding age, fecundity and spawning interval are unknown. Koelz (1929) reported that spawning occurs during August and September and suggested that some females may spawn every second year. Species Movement: No information is available. Behaviour I Adaptability: An assessment of the degree of tolerance of this species to human disturbance is dif
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