Weight loss and change of condition factor during fixation of Pacific herring, Clupea harengus pallasi, eggs and larvae

Dry weights of unfixed eggs and larvae of Pacific herring, Clupea harengus pallasi , taken at six different periods during development, were compared to those of larvae stored for 10 days in fixatives varying in salinity (0, 15, 28%‰) and formalin (4, 10, 20%) concentration. In most instances there was some weight loss of the fixed specimens. In general weight loss varied inversely with salinity and formalin concentration and was greater in larvae than eggs. Weight loss was greatest in recently fertilized eggs and decreased in older eggs. Weight loss in recently hatched larvae varied from 19 to 36% depending upon the salinity and formalin concentration. Weight loss varied inversely with larval size and fixation increased weight in some large larvae. Weight change during fixation could result in an artificial inflation of the estimate of condition factors, particularly in the younger smallest larvae.