| Abstract/Description or Keywords |
Benthic Invertebrates have been used as indicators of water quality and the overall health of the Slocan River Ecosystem for 4 years. Invertebrates are studied because they are important indicators of biodiversity and productivity of aquatic systems. To date, however, collections have occurred in Autumn as per CABIN methodology and at headwaters & lower reach sites on the main river. The Streamkeepers have also been studying fish populations since 2005 when changes in fishing regulations occurred. The river was opened to catch and release angling in that year and that year was the first opening of the rainbow trout fishery on the river in 13 years. Snorkel surveys done in 2005 through 2007 by biologists indicate a significant increase in rainbow trout populations. White fish have routinely been counted informally and, in the past, approximately 10 white fish were observed for every 1 rainbow. In 2007, a “serious decline” in whitefish population was observed. In an effort to better understand fish population dynamics and links between numbers, age class and species of fish in relation to food source, a study of benthic macroinvertebrates, the fish’s main food source, was recommended. Many invertebrate species complete their life cycle by developing wings and leaving the water during the early spring. Midges and a variety of Mayfly (Baetidae) are known sources of food that emerge in “hatches” in early March. Fishermen are aware of this Mayfly and call it the “blue winged olive”. Once larvae reach maturity they transform to sub-imagos. This is done in large numbers and called the “hatch”. The emerging insects provide an important source of nutrients to fish that are becoming active after the winter. Hence, spring counts of invertebrate numbers and size can give a good indication of the volume and type of food available to fish. Both white fish and trout share the same habitat and surveys have identified specific pools where mixed species of fish spend the winter. One such pool is located approximately 2 kilometers south of Slocan Park just below the “Rustic Rooster Bed and Breakfast”. The riffle habitat just above the large pool was chosen as an appropriate site for invertebrate Collection. |
