Temporal variation in size at maturity of the snail Zidona dufresnei from the southwestern Atlantic Ocean after ten years of fishery exploitation

Abstract

The snail Zidona dufresnei is a marine resource that has been continually exploited by trawling over the past 20 yr. Although research into this fishery started 10 yr ago, no regulations have been implemented to date. In the present study, the histologically estimated size at maturity of both sexes of Z. dufresnei was found to be 131 mm for females and 128 mm for males. These values are lower than those determined in 1999 for Z. dufresnei in the same fishing area. In females, significant differences in size at first maturity were found between 1999 and 2009 in the size classes 121 to 150 mm and 151 to 180 mm. In males, significant differences between years were found in the size class 121 to 150 mm. This is the first report of changes in the size at first maturity of marine snails sub- jected to fishery exploitation. Effects of Z. dufresnei reproductive cycle, growth rate, size at maturity and population management should be taken into account in Z. dufresnei fishery.