. California fish and game. Fisheries -- California; Game and game-birds -- California; Fishes -- California; Animal Population Groups; Pêches; Gibier; Poissons. STUNTED BROOK TROUT IN AN ALPINE LAKE 207 pituitary, thyroid, and thymus when present) were prepared from 13-year-olds captured in late autumn and from 1- to 4-year-old brook trout caught in a neighboring lake. No clear evidence of senile degeneration was found in com- parisons of these materials, although several deficiencies were apparent in the old trout. The aforementioned calcification and pigmentation were prevalent; atrophic sk
. California fish and game. Fisheries -- California; Game and game-birds -- California; Fishes -- California; Animal Population Groups; Pêches; Gibier; Poissons. STUNTED BROOK TROUT IN AN ALPINE LAKE 207 pituitary, thyroid, and thymus when present) were prepared from 13-year-olds captured in late autumn and from 1- to 4-year-old brook trout caught in a neighboring lake. No clear evidence of senile degeneration was found in com- parisons of these materials, although several deficiencies were apparent in the old trout. The aforementioned calcification and pigmentation were prevalent; atrophic skeletal muscle fibers and lowered profiles in epithelial cells were occasional; liver cells were starved, as opposed to abundantly vacuolated; some kidneys had noticeably undersized glomeruli, possibly indicative of waning func- tion; the gonads of most maturing specimens had one or more of various dystro- phies such as gross deformities of testes (Figure 1), isolated spermathecal cysts, sperm stasis at the spermatid stage, tailless spermatozoa, ovaries filled with resorbing ova and shriveled oocytes, or ovarian connective-tissue barriers to the release of eggs. Of these variations from the normals of young trout, only the first may be considered unequivocally age-related; the others could as easily be the result of marginal nutrition. The morphology and distinctive staining proper- ties of secretory cells in pituitary, thyroid, inter-renal, and pancreatic tissues indicated normal or near-normal function in old trout. The tissues of hemopoiet- ic and cardiovascular systems were essentially unchanged with >>2-912 S. W. lAMH PORTLAND 8, OF iiiHiiiiiiiiiiiiiiiiiHiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiimiiiimmmm FIGURE 1. Testis of 13-year-old Bunny Lake brook trout, showing general underdevelopment with lobular deformity. Photograph by Fish and Wildlife Service, November 1963. In 1965, surveys were completed on the gonads of one female and four male 14-year-olds that
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