SPERM MORPHOMETRY IN THE ATLANTIC SALMON

This study sampled sperm from wild Atlantic salmon to explore relation ships between sperm form and function. Detailed measurements of sperm morphometry (head, flagellum and total length) and sperm activity (lon gevity and % motility) were made from 24 reproductively active males ( 13 anadromous and 11 mature parr) on two occasions post-stripping. The re was significant between-male variance in total sperm length but thi s variance was not related to body size. Despite this variance in sper m length, no relationships were found between a male's sperm activity (longevity or % motility) and his sperm length. There were also no rel ationships between sperm head length and flagellar length, and no evid ence for a trade-off between sperm length and numbers. It is suggested that the significant between-male variance in sperm morphometry suppo rts diploid control of spermatogenesis: haploid expression of sperm ph enotype would be manifested as profound variance within (and not betwe en) each male's spermatozoal characteristics. (C) 1998 The Fisheries S ociety of the British Isles.