1 January 2005 Relating Results of Chronic Toxicity Responses to Population-Level Effects: Modeling Effects on Wild Chinook Salmon Populations
Julann A. Spromberg, James P. Meador
Author Affiliations +

Standard toxicity tests assess the physiological responses of individual organisms to exposure to toxic substances under controlled conditions. Time and space restrictions often prohibit the assessment of population-level responses to a toxic substance. Compounds affecting various toxicity endpoints, such as growth, fecundity, behavior, or immune function, alter different demographic traits and produce different impacts on the population. Chronic effects of immune suppression, reproductive impairment, and growth reduction were examined using life history models for Chinook salmon (Oncorhynchus tshawytscha). Modeled immune suppression acted through reductions in age-specific survival, with first- and second-year survival producing the greatest changes in the population growth rate (λ). A 10% reduction in various reproductive parameters all produced a similar λ, but different sensitivity and stable age distributions. Growth reduction models incorporated effects to both survival and reproduction and produced additive effects. Overall, model output indicated that for Chinook salmon, alteration of first-year survival has the greatest relative impact on λ. Results support the importance of linking toxicity endpoints to the demographic traits that they influence and help generate toxicity tests that are more relevant for the species. Life history modeling provides a useful tool to develop testable hypotheses regarding specific and comparative population-level impacts.

Julann A. Spromberg and James P. Meador "Relating Results of Chronic Toxicity Responses to Population-Level Effects: Modeling Effects on Wild Chinook Salmon Populations," Integrated Environmental Assessment and Management 1(1), 9-21, (1 January 2005). https://doi.org/10.1897/IEAM_2004a-005.1
Received: 22 February 2004; Accepted: 1 June 2004; Published: 1 January 2005

This article is only available to subscribers.
It is not available for individual sale.

Chinook salmon
chronic toxicity
Life history modeling
Population-level effects
Get copyright permission
Back to Top