| Affiliation: | (1) CONICET Lab Invertebrados Depto Ciencias Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria Pab II C1428EHA, Buenos Aires, Argentina;(2) Alfred Wegener Institute for Polar and Marine Research, PO Box 120161, 27515 Bremerhaven, Germany;(3) Museo Argentino de Ciencias Naturales, Av Ángel Gallardo 470, Buenos Aires, Argentina |
| Abstract: | The volutid snail Zidona dufresnei is a benthic top predator in the Mar del Plata (Argentina) shelf area where it was subjected to unregulated commercial exploitation for more than 20 years. So far there is no stock management, and hitherto even the most basic information on population dynamics of this species is missing. Annual formation of internal shell growth bands visible by x-ray was confirmed by the stable oxygen isotope record in the shell carbonate that reflects seasonal oscillations in water temperature. A Gompertz growth function ( , K=0.211 year–1, t0=5.496) fitted 142 pairs of size-at-age data (30 shells) best. Maximum individual production amounted to 26.8 g shell-free wet mass (SFWM) at 115 mm shell length. Based on a size-frequency distribution derived from commercial catches, annual mortality rate of Z. dufresnei was estimated to be 0.61 (±0.21) year–1.Communicated by O. Kinne, Oldendorf/Luhe |
