Monitoring the Effects of Pulp and Paper Effluent Is Restricted in Genetically Distinct Populations of Common Bully (Gobiomorphus cotidianus)

Abstract

The common bully (Gobiomorphus cotidianus), a small-bodied New Zealand native fish species, was used to monitor population impacts of multiple effluents in the Tarawera River, New Zealand. In an initial survey, the absence of reproductive development at the expected spawning time for common bully was observed in a population downstream of effluent discharges. Subsequently, we examined the hypotheses that the observed changes were due to effluent exposure, migratory patterns, or genetic differences between populations. Liver detoxification enzyme activity and stable isotopes provided evidence against upstream migration of sexually mature bully. The observed presence of developed gonads in the downstream population during winter season resulted in the rejection of the hypothesis that reproductive failure was due to effluent exposure, and it was concluded that there were substantial differences in reproductive timing. Genetic analyses of two upstream, one downstream, and one population from a nearby coastal river indicated the upstream (reference) and downstream (effluent exposed) bully in the river formed genetically distinct populations. The identification of a nearby river population with similar reproductive timing and high genetic similarity to the effluent-exposed population suggests that the observed differences in the genetics of the downstream population were not caused by effluent exposure. The genetic analysis did highlight the lack of downstream dispersion and gene flow in the river which could possibly be related to anthropogenic stress.

Distinct migratory and non-migratory ecotypes of an endemic New Zealand eleotrid (Gobiomorphus cotidianus) – implications for incipient speciation in island freshwater fish species

“…The absence of migratory fish in upstream Tarawera could be explained by limited upstream migration through the paper mill effluent outfalls [52], or by inherited behavioural patterns. The substantial variations observed in the oculoscapular canal system are clearly not evenly distributed across the sample sites.…”

“…About 35 km downstream of the waterfall the river enters an extended area of flat land before reaching the Pacific Ocean. No physical barriers limit downstream dispersal of fish within the Tarawera River, whereas upstream dispersal may be limited [52]. The Kaituna River, which originates in the nearby Lake Rotoiti, drains into a coastal area before also reaching the Pacific Ocean.…”

“…To test for possible morphological differences between migratory types, the otolith data were contrasted with the distribution of oculoscapular canal morphotypes (as determined from the pore openings of the canals; Figure 2). Previous work suggested the presence of distinct summer and winter spawning populations in the Tarawera River [52]. Thus, we included data on the gonadal development (gonadosomatic indices) to test for temporal reproductive isolation among migratory and non-migratory stocks.…”

Seasonal changes in reproductive endpoints inTrichomycterus areolatus(Siluriformes: Trichomycteridae) andPercilia gillissi(Perciformes, Perciliidae), and the consequences for environmental monitoring

“…Fish have played an increasing role in environmental monitoring programs that are focused on detecting the impacts of industrial effluents in many countries, including Canada (Munkittrick 2004;Lowell et al 2005;McMaster et al 2006), USA (Sepúlveda et al 2002;Theodorakis et al 2006;Yeom & Adams 2007) Sweden (Larsson et al 2000;Sandström & Neuman 2003), Finland (Donald 1997;Karels & Oikari 2000) and New Zealand ( Van den Heuvel et al 2007). Less attention has been paid to this type of environmental monitoring in South America, until quite recently.…”

Health status of native fish (Percilia gillissi and Trichomycterus areolatus) downstream of the discharge of effluent from a tertiary‐treated elemental chlorine‐free pulp mill in Chile

“…This estrogenic response differs from the results in the Northern Hemisphere. Worldwide, the principal response in sites downstream of pulp mill discharge has been a reduction in gonad size, as has been seen in Canada [7,[33][34][35][36][37][38][39], the United States [40][41][42], Sweden [43], Finland [44], and New Zealand [45], where the possible causes are a reduction in the fish's steroid production capacity [46][47][48]. The alterations we observed at the reproductive level in individuals downstream of the discharge could be responsible for the differences in the size structure of the populations of both species, in which there is a temporal tendency toward a loss of smaller sizes.…”