Assessment of status of white sucker (Catostomus commersoni) populations exposed to bleached kraft pulp mill effluent

Abstract

Credible ecological risk assessments often need to include analysis of population-level impacts. In the present study, a predictive model was developed to investigate population dynamics for white sucker (Catostomus commersoni) exposed to pulp mill effluent at a well-studied site in Jackfish Bay, Lake Superior, Canada. The model uniquely combines a Leslie population projection matrix and the logistic equation to translate changes in the fecundity and the age structure of a breeding population of white sucker exposed to pulp mill effluent to alterations in population growth rate. Application of this density-dependent population projection model requires construction of a life table for the organism of interest, a measure of carrying capacity, and an estimation of the effect of stressors on vital rates. A white sucker population existing at carrying capacity and subsequently exposed to pulp mill effluent equivalent to a documented exposure experienced during the period 1988 to 1994 in Jackfish Bay would be expected to exhibit a 34% to 51% annual decrease in recruitment during the first 5 yr of exposure and approach a population size of 71% of carrying capacity. The Jackfish Bay study site contains monitoring data for biochemical endpoints in white sucker, including circulating sex steroid concentrations, that could be combined with population modeling to utilize the model demonstrated at the Jackfish Bay study site for investigation of other white sucker populations at sites that are less data-rich.

Linking mechanistic toxicology to population models in forecasting recovery from chemical stress: A case study from Jackfish Bay, Ontario, Canada

“…The first step is to explicitly identify adverse outcomes observed in the field, based on the collected data. In the present study, 2 adverse outcomes were recorded in exposed fish: decreased fecundity (number of eggs produced per female) and delay in maturation of females (as reflected by the difference in the distribution of age structure of breeders at the impacted Jackfish Bay site in comparison with the reference site at Mountain Bay [7]). A subsequent step is to then identify potentially useful data from lower biological levels of organization based on 2 factors: plausible linkage to the adverse outcome(s) of concern and availability of a robust dataset for the population/situation of concern.…”

“…Ages of female fish were determined by counting annular rings on dried opercula (a detailed description of field methods can be found in McMaster et al [19] and Munkittrick et al [20]), and female breeders were stratified according to study site and year of collection for use in data analysis and construction of the population model [7].…”

“…Examining the viability of chemically impacted populations is a primary goal of ecological risk assessment [1][2][3][4][5][6][7]. Modeling approaches link individual-level responses recorded in the laboratory or field and risk to the population as a whole and serve as a key component for analysis of population-level impacts of chemical stressors.…”

“…The application of models offers an effective methodology for addressing the toxicity of an increasing number of chemicals and chemical mixtures for risk assessment [3,4,8]. Furthermore, population modeling, in combination with field-based monitoring assessments, may provide the ability to predict population dynamics over time and across sites in response to remedial actions [5,7,[8][9][10][11][12].…”

“…The white sucker population at Jackfish Bay, a Great Lakes Area of Concern, has been monitored as part of ongoing field studies that collectively span over 20 yr [19][20][21]. For the present analysis, we used effects-based monitoring data from 1998 to 2007 at the Jackfish Bay site in combination with a population model for white sucker developed by Miller et al [7]. That study described construction and application of a density-dependent population model for white sucker exposed to pulp mill effluent at the Jackfish Bay site to examine the impact on population status for the period of 1988 to 1994.…”