A consistent, efficient method for marking brown trout (Salmo trutta) by intracutaneous injection of dyes was developed. Experiments were then conducted with over 150 chemicals in an effort to obtain easily identifiable, long-lasting, weightless, and harmless colored marks. Thirteen dyes in seven colors were durable. The best were National Fast Blue 8GXM, a water-soluble blue dye, and hydrated chromium oxide, an insoluble green pigment. The former most nearly meets the requirements for a satisfactory injection dye. It is non-toxic, retained on all fish for at least two years, and can be applied at a rate of 400 trout per hour. Hydrated chromium oxide was retained on all fish for one year. Encouraging results were also obtained with plastics. In field tests with pond brook trout (Salvellnus /ontinalis) these two dyes were retained on all fish after one year with no adverse effects on growth and survival. A fourmonth test with winter flounders (Pseudopleuronectes americanus) demonstrated mark permanence for the entire period. A new high pressure jet-injection system appears promising.Evidence suggests that depth of injection and growth rate of fish are determinants of mark permanency. Dye fixation in fish skin was not associated with inflammatory cell response.
A variety of mono- and difluoroacetylsilanes and the corresponding silyl enol ethers were prepared from trifluoroethanol and chlorotrialkylsilanes in the presence of LDA through retro-Brook rearrangement. Sterically demanding silyl groups, especially those bound to oxygen, resulted in higher yields of difluoroacetylsilanes. The yields of difluoroacetylsilanes were also dramatically affected by the method of the termination of the reaction. Difluorohaloacetylsilanes were prepared from the corresponding difluoroethenyl silyl ethers with electrophilic halogenating reagents in good yields. A gamma-fluorinated beta-diketone 9a was prepared from monofluoroacetyltriisopropylsilane by nucleophilic acylation with methyl trifluoroacetate.
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