A simulation model of how life history strategies mediate pollution effects on fish populations
- National Oceanic and Atmospheric Administration, Beaufort, NC (United States)
Pollution effects on fish populations were estimated with a simulation model, using Leslie matrices. Results from changing only first-year survival rate (S[sub o]) have already been published (Schaaf et al. 1987). This paper explores the effects of perturbing both S[sub o] and the adult survival rate (S[sub i]) for 12 spatial-temporal stocks. Most stocks examined are more sensitive to permanent change in S[sub i] than to changes in S[sub o]. The relative importance of these two rates in determining the population growth rate ([lambda]) depends upon the age distribution of the expected lifetime egg production of age i females (V[sub i]). In turn, the vector V[sub i], as measured by its mean and standard deviation, is shown to vary among geographic or temporal stocks of a single species. Hence, we quantify the impact on population size of destroying a fixed percentage of habitat, relative to where and when it occurs (i.e., relative impact on S[sub i] and S[sub o]). For example, destroying 1% of the Atlantic menhaden habitat would reduce [lambda] by 0.8% and the population by 8.0% in 10 yr, if the impact affected only adults (e.g., offshore in winter). If the 1% habitat destruction all occurred in the estuaries, affecting juveniles as well, [lambda] would be reduced by almost 5%, and in 10 yr drive the population down to 58% of its former equilibrium. We show that knowledge of the mean and variance of the age distribution of V[sub i] permits prediction of relative sensitivity among species to pollution. Within species, this knowledge of V[sub i] permits comparison of the effects of impacting different life stages, and at different times and places. 8 refs., 7 figs., 1 tab.
- OSTI ID:
- 7104443
- Journal Information:
- Estuaries; (United States), Vol. 16:4; ISSN 0160-8347
- Country of Publication:
- United States
- Language:
- English
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