Population models of farmed abalone Haliotis diversicolor supertexta exposed to waterborne zinc
2004
Chen, B.C. | Liao, C.M.
A stage-classified demographic method was performed to investigate the effects of increased waterborne zinc (Zn) concentrations on the population dynamics of abalone Haliotis diversicolor supertexta. We reanalyzed the results of a 7-day acute and a 28-day chronic toxicity bioassays to examine the survival and growth performances when exposing abalone to different levels of zinc stresses. An energy-based biological approach was adopted to model the effects of zinc on fecundity. These data provided stage-specific schedules of vital rates that were used to parameterize a projection matrix model for abalone. Simulations were carried out to produce temporal population abundance changes under seven exposure scenarios including a control group and six treated cohorts ranged from 0.03 to 1 mg l(-1) Zn. Model manipulations indicated that a reduction of individual growth rate was observed at an exposed Zn concentration greater than 0.12 mg l(-1), whereas the significant influence of survivorship was occurred until the Zn concentration reached 0.25 mg l(-1). For all treatments, Zn induced a slight decrease in fecundity. The asymptotic population growth rate decreased from lambda=1.00 for the control group to lambda=0.9968 for abalone population exposed to 1 mg l(-1) Zn, indicating a potential risk of population intrinsic growth rates for abalone exposed to higher levels of waterborne Zn. These findings provide a pivotal effort for setting of the ambient water quality criterion for protecting the aquacultural species.
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