I was glad to see "Fact and Fiction in Spawntaking" by Wood and Dunn (1948) in a recent issue of the PROGRESSIVE FISH CULTURIST. Having spent two seasons at the Yellowstone Park station, I also attempted to find ways of increasing the efficiency of fertilization and several years ago conducted a few experiments along these lines. From these experiments I obtained some "facts and fiction" that I believe are particularly germane and will be of interest to anyone who spawns fish.

I often dreamed of some Utopian technique for spawning fish--a technique that would insure 100-percent fertilization. My approach to this was an attempt to find a solution that would keep the sperm viable and active for a period of minutes rather than seconds and one that would allow eggs to remain receptive to the sperm for the same period.

The work of Ellis and Jones (1939) indicated that a solution of comon salt would prolong the life of fish sperm, although the work of Schlenk and Kahmann (1938) indicated that a more complex solution must be used. I therefore tested on sperm many solutions which waried in composition, strength, pH, and temperature. None of these prolonged viability to the point where 100-percent fertillzation could be expected after a few minutes" exposure at best. There was no difficulty in prolonging the fertilizable life of the egg: a plain salt solution was found quite effective, as mentioned by Rutter (1904).