I believe you're right, wwwebtrader, about the picture on page 89 of my copy of
Skin and Scuba Diver being attributable to Fred Freeman, who published in pulp magazines such as
Argosy .
Just now I located a colour version online of the monochrome image in the Borgeson and Speirs volume. As you can see, the coloured picture is signed by Fred Freeman, but the peripheral detail is somewhat different:
Anyway, it's on the Pinterest website at
https://www.pinterest.co.uk/pin/405535141428572238/ .
What a grin on the underwater hunter's face as he spears the toothy shark above him!
Postscript: Just found the front cover, on the Pinterest website at
https://www.pinterest.co.uk/pin/431993789241314662/:
Perhaps the
Skin and Scuba Diver book illustration came from the article inside the July 1952
Argosy issue entitled "Duel in the Sea"? The contents of the issue can be found at
http://www.philsp.com/homeville/gfi/t275.htm#A4020.