In recent years, studies in the upper Bulkley River upstream of Houston have noted elevated levels of bacteria, nutrients and attached algae (periphyton). A 1992 fisheries study in the upper Bulkley at Houston found fish species composition was dominated by longnose dace and to a lesser extent longnose suckers, together accounting for about 90% of all fish in the study area. This pattern occurred upstream and downstream of the sewage treatment plant discharge and is believed to reflect a combination of low stream flows, warm temperatures, and perhaps eutrophication in this section o f the river, providing longnose dace with a competitive feeding advantage over steelhead and salmon juveniles.