Born in Waterdown, Ricker was an authority in the taxonomy of stoneflies, and evolved an elegant classification which his fellow entomologists praised as "a thing of beauty and simplicity that made evolutionary sense" [REF].
In his 1969 paper, Food from the sea, he reasoned that the quantity of food that could be harvested from the sea would be 150-160 million tonnes or 2.5 times the level in 1968.