Comparing responses in the performance of sentinel populations of stoneflies (Plecoptera) and slimy sculpin (Cottus cognatus) exposed to enriching effluents T.J. Arciszewski n , K.A. Kidd, K.R. Munkittrick Canadian Rivers Institute and Department of Biology, University of New Brunswick, Saint John, NB, Canada E2L 4L5 article info Article history: Received 18 March 2011 Received in revised form 3 June 2011 Accepted 12 July 2011 Available online 3 August 2011 Keywords: Monitoring Plecoptera Fish Effluent Population performance Life history abstract Programs in Canada that assess the effects of wastewater discharges on organisms, such as Environ- mental Effects Monitoring (EEM), primarily focus on fish populations and benthic invertebrate communities. Although these methods are widely accepted, there are many situations where fish monitoring is difficult and benthic community data is difficult to interpret; in these instances alternative approaches should be used. There are, however, few alternative methods available. One potential alternative is to use invertebrate population endpoints to determine effects in the receiving environment. In this study we examined effects of sewage and pulp mill effluents in the Saint John River, New Brunswick, on two stonefly genera (Plecoptera, Perlidae, Acroneuria spp. and Paragnetina spp.) and compared the responses to those of a small-bodied fish, the slimy sculpin (Cottus cognatus). Stonefly measurements included condition, developmental stage, gonad weight, and size upstream and downstream of sewage and a pulp mill discharge. Condition, developmental stage, and absolute gonad weight were greater in Paragnetina spp. downstream of the sewage discharge. Acroneuria spp. showed persistence of the late developmental stage downstream of the sewage inputs. Slimy sculpin exposed to sewage effluents also showed increased condition, but the impacts downstream of the pulp mill effluent were inconsistent in both sculpin and Paragnetina spp. Our findings suggest that stonefly populations and slimy sculpin respond to effluents in similar ways and that the responses of large long- lived invertebrate populations, such as stoneflies, may be a viable alternative to fish population monitoring in environmental assessments of point source discharges. & 2011 Elsevier Inc. All rights reserved. 1. Introduction Canadian Environmental Effects Monitoring (EEM) programs apply to pulp and paper mills and metal mines and are being developed for municipal discharges. The EEM program requires that regulated dischargers periodically evaluate whether effluents in compliance with national discharge guidelines have residual biolo- gical effects on ‘fish’, ‘fish habitat’, and ‘the use of fish resources’ (Glozier et al., 2002; Ribey et al., 2002; Walker et al., 2002). In exposed and reference areas, the ‘fish’ survey measures changes in the population performance of a sentinel species and alterations to ‘fish habitat’ are estimated using the structure of the benthic invertebrate community (Environment Canada, 2005). In EEM programs effects are used to direct the focus of future studies to determine the potential cause of the previously documented effects; facilities with confirmation of no impacts can reduce the intensity of their monitoring. There are many situations where the design options and interpretation of adult fish surveys are limited due to the local distribution of a species, confounding factors, sampling restric- tions, other concerns about threatened or endangered species, and difficult or dangerous sampling conditions (Courtenay et al., 2002; Munkittrick et al., 2002). In instances where an appropriate fish sentinel cannot be identified or where spatial or ecological factors limit the study design, an investigator can use either a modified or an alternative method that has been approved by Environment Canada, such as mesocosms, caged bivalves, marine bivalves, or a non-lethal fish study (Environment Canada, 2005). In some circumstances, no alternative or modified methods are available. For instance, effluent from some metal mines is dis- charged to small receiving streams that have no resident fish species. Studies in these environments have relied on information from the benthic invertebrate community (Lowell et al., 2007). While both sets of information are useful, fish population and benthic invertebrate community endpoints respond differently Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/ecoenv Ecotoxicology and Environmental Safety 0147-6513/$ - see front matter & 2011 Elsevier Inc. All rights reserved. doi:10.1016/j.ecoenv.2011.07.010 n Corresponding author. E-mail address: tim.arciszewski@gmail.com (T.J. Arciszewski). Ecotoxicology and Environmental Safety 74 (2011) 1844–1854