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Survival, Performance, and Resistance to Myxobolus cerebralis Infection of Lake Trout × Brook Trout Hybrids
Author(s) -
Wagner Eric,
Arndt Ronney,
Brough Mark,
Wilson Chris,
Nelson Gordon
Publication year - 2002
Publication title -
north american journal of fisheries management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.587
H-Index - 72
eISSN - 1548-8675
pISSN - 0275-5947
DOI - 10.1577/1548-8675(2002)022<0760:spartm>2.0.co;2
Subject(s) - salvelinus , trout , fontinalis , biology , hatchery , hybrid , fishery , hatching , zoology , ecology , fish <actinopterygii> , botany
The survival, performance, and susceptibility to Myxobolus cerebralis infection of the two possible crosses between lake trout Salvelinus namaycush and brook trout S. fontinalis were compared over a 4‐year period in Causey Reservoir, Utah, an oligotrophic reservoir. Splake were produced by crossing female lake trout with male brook trout and brookinaw by crossing female brook trout with male lake trout. In the hatchery, significantly more splake eggs survived from fertilization to hatching than did brookinaw eggs, but once the fish began feeding survival did not differ between the two hybrids. A total of 54,645 splake and 42,356 brookinaw were stocked in the reservoir, and over the course of the study, 92 splake and 69 brookinaw were recovered from spring and fall gill‐net sets. Survival, average weight, average length, and condition factor did not significantly differ between the two hybrids for any of the 4 years. Differences in susceptibility to infection by M. cerebralis between the two hybrids were compared in the reservoir and in laboratory tests in which fish were exposed at either 5 or 10 weeks posthatch. No M. cerebralis myxospores were found in either hybrid during the first 2 years of reservoir study, after which the prevalence ranged from 7.5% to 25% for splake and from 0% to 25% for brookinaw. Infection prevalence did not significantly differ between the two hybrids for any of the sampling periods. In controlled exposure tests, prevalence of M. cerebralis did not differ significantly between trout exposed at 5 weeks posthatch (splake = 88.4%, brookinaw = 77.1%) or at 10 weeks (splake = 100%, brookinaw = 96.4%). Our results suggest that brookinaw and splake are similar in growth, survival, and resistance to the causative agent of whirling disease after the fish reach the free‐swimming fry stage. For fishery programs that rely on wild lake trout for splake production, use of brookinaw could result in significant manpower savings without compromising poststocking survival.