| Summary: | Thesis (M.Sc.)--Memorial University of Newfoundland, 1985. Biology Bibliography: leaves 103-115. Newfoundland has numerous populations of landlocked Atlantic salmon (Salmo salar). Several of these populations are stunted, exhibiting a marked reduction in size at any age compared with other anadromous and landlocked populations. A population of stunted landlocked salmon from 5 Mile Pond East on the Avalon Peninsula was investigated. Data collected on ecology and life history reveal the population to be an extremely slow-growing, short lived form of Atlantic salmon. -- Anadromous and landlocked Atlantic salmon examined at the smolt stage revealed a difference in the degree of smoltification and salinity tolerance exhibited by the two forms. Anadromous fish had a decrease in lipid, increase in water content and the increased salinity tolerance characteristic of true smolts. While wild landlocked 5 Mile Pond East fish experienced a similar reduction in lipid and increase in water, neither they, nor cultured landlocked salmon survived a challenge to sea water. -- The two pure lines and the reciprocal hybrids between the early maturing stunted 5 Mile Pond East fish and a later maturing anadromous form were reared in the laboratory for a period of 2.5 years. Ninety percent of female parr of the dwarf landlocked strain matured at age 2+ while no females of the anadromous form matured at this time. Ovary weight differed in the two pure forms at age 0+ and the numbers, size and stages of previtellogenic oocytes also differed at age 1+. Ovarian patterns of development and the time of onset of sexual maturation in the two hybrid forms appeared intermediate to that of the parental forms.
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