Extinction Risk of Exploited Wild Roach (Rutilus rutilus) Populations Due to Chemical Feminization

Abstract

A model that assesses risks posed by feminization to wild populations of roach was developed. A population life table matrix model that considered both sexes and a newly developed fertility kinetic function was applied to calculate the intrinsic population growth rate (λ) of roach populations where males had been feminized. The maximum sustainable yield (MSY) was used to quantify the effect of various degrees of feminization on sustainability of exploited fisheries. Risk of extinction was calculated for wild roach populations. The results of the simulations suggested that (a) In the absence of fishing pressure λ would only be decreased 1.5-1.7% even in the presence of a 100% incidence of intersex; (b) in the presence of selective fishing, the occurrence of intersex could significantly increase the extinction risk of local roach populations; (c) the benchmark value for the severity index of intersex and sex ratio required for a sustainable population of roach were estimated to be 1.13 and 0.57, respectively. The approach presented here provides a tool to (1) understand effects of male's feminization on population dynamics; (2) assess extinction risk of wild roach populations from feminization; (3) assist environmental managers in making policy decisions relative to fishery resource conservation.

Reproductive health of yellow perch Perca flavescens in selected tributaries of the Chesapeake Bay

“…Feminization of male fishes as evidenced by testicular oocytes or intersex (Jobling et al, 1998;Kavanagh et al, 2004;Dietrich and Krieger, 2009;Blazer et al, 2012) and production of Vtg (Denslow et al, 1999;Jones et al, 2000;Dang et al, 2011;Vajda et al, 2011) has been observed in numerous fish species. In a few cases, population effects are reported (Kidd et al, 2007;An et al, 2009). The results of this study (a very low prevalence of male YP with measurable plasma Vtg or testicular oocytes) indicate aberrations in or disruption of estrogen receptor signaling are unlikely the cause of reduced reproductive success of YP populations in the urban rivers of interest.…”

Multiple linear regression model for bromate formation based on the survey data of source waters from geographically different regions across China

“…As shown in Table 2 Table S3, and the MSC values of these models are listed in Table S4. The MSC value of model 3 was 2.01, which was reasonable (An et al 2009). The relatively good fit was ; the blue circles in the figure were the data of this study, and the triangles were the data from a previous study (Legube 1996)).…”

“…To avoid over-fitting and to select the optimal model, MSC (An et al 2009) were applied to compare the relative goodness of fit between the model developed in this study and those of previous studies while considering a trade-off between the model complications and model specification errors, as described in SI section I (Model selection). A contour plot was used to reveal the interaction between alkalinity and TOC in the contribution to BrO 3 − formation using Origin 8.0. , except for one outlier in groundwater, which should be attributed to seawater intrusion.…”

“…Since ammonia and Br − have been included in most of previous model studies, these two parameters were also chosen for the model. The MSC method was used to balance the model complication and specification errors for selection of the best model (An et al 2009). As shown in Table 2 Table S3, and the MSC values of these models are listed in Table S4.…”

Adding Value to Ecological Risk Assessment with Population Modeling

“…For example, An et al (2009) evaluated the effects of male feminization due to exposure to endocrine disrupting chemicals (EDCs) on roach (Rutilus rutilus) populations in European rivers. Changes in population growth rate and extinction risk due to feminization were evaluated in populations with and without fishing mortality.…”