Acid stress increases pelvic spine asymmetry in juvenile three-spined sticklebacks

In the evaluation of the effect of acidic water on the symmetrical developm ent of the pelvic spines in juvenile three-spined sticklebacks Gasterosteus aculeatus, directional rather than fluctuating asymmetry was found, with l eft spines being, on average, longer than the right. Fish that were exposed for a period of c. 2 months to acidic pH levels grew significantly more as ymmetrical pelvic spines. than their control full-siblings held in unmanipu lated water. Average spine size was not affected by the experimental treatm ent. (C) 2001 The Fisheries Society of the British Isles.