7 — SUMMARY OF OPERATIONS ON CONTRACT NO, W=28-094-eng-33 Rr 9 7 FOR THE MONTH OF JANUARY 1948, The basic program of the Applied Fisheries Laboratory of measuring the effect of X-rays upon aquatic organisms, was further expanded by the inclusion of amphipod experiments. Sections I and II# Egg lots from the Fall 1947 spawning of chinook salmon adults from irradiated and control stock have continued developing. k Ey ; s¢ wir bss za aN & 3 5 en) Mortalities have , been recorded and the dead preserved for further studyin all 15 lots, stock were not yet ready to be spawned and so should not be considered in the comparison because their high mortalities mask the difference that is evident when only the remaining 13 lots are considered. $8 Heide a he Eevesremmee,! It is believed that Lot 13 of the controls and Lot 14 of the irradiated o By: I. The average per- centage mortality through January 31, 1948 for the 7 control lots was 6,5 compared to a value of 23 for the 6 lots from 100 r irradiated stock, The value of "t" was 2.26 which, for 11 degrees of freedom is slightly beyond the 5 per cent level, and is considered significant, a As these animals develop studies will be made of the numbers nalformed and degree and kinds of abnormality. Some modifications from normal structure are now evident but it will be possible to determine the extent of variation from the normal with greater accuracy after the yolk sac period has passed and the active feeding period starts, II. Basic Xeray studies were initiated during the month by exposing amphipods to varying amounts of X-ray irradiations. These studies were designed to more fully understand the effect of irradiations on various members of the animal kingdom. *Section numbers refer to the Project Chronology Chart, revised January 9, 1947. QE pos ARCHIVES

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