Dissolved Oxygen is a main component of water quality and one of the tests we were really interested in seeing the results of. This blog is going to talk about the importance of dissolved oxygen on the native species to the area with is the Eastern Brook Trout, and another species not native but now a wild population is the Brown Trout. Both are species with naturally sustained populations in the Dog River.
The difference in the wild verse native is that both populations are reproducing naturally, however brown trout were introduced from Germany and now a self-sustained population, while brook trout are native to Northeastern North America. Both are very similar species and require the proper water quality to sustain their populations. With dissolved oxygen trout thrive at levels above 11 mg/L, but can still survive in as low as 8 mg/L. The levels we found from our data in the Dog were averaging at 12 mg/L. As clearly obvious this is very comfortable levels for trout and lead to healthy spawning waters and healthy for young fish fry and eggs that require high levels for the fastest growth rate.
Another area dissolved oxygen effects trout is through their food sources of insects. 90 percent of a trout’s diet comes from the nymph stage of insects, which is when they are developing and live on the bottom of the river. You can tell the levels of oxygen easily by lifting rocks in the ripples and seeing what different insects are on these rocks. One key insect that is a key to clean and very well oxygenated water is the stone fly. As found in the dog there is a stonefly population. With lower levels of oxygen these insects cannot live, and you find insects that represent poor oxygen levels such as scuds. As insect’s life takes up 99 percent of a trout’s diet, the other 1 percent is other fish, which is all tied in to oxygen levels. If there are these lower levels a population is not going to sustain itself.
All these results however lead to an interesting question that is, why is there not a greater trout population in the Dog River. Not saying that there is no trout, however with the levels and temperatures measured the Dog on paper appears to be a world class fishery like it once was. There are plenty of assumptions and theories behind this but the question still sits in the back of my mind.
Aside from that question, this blog is to address the importance of dissolved oxygen and its role in a trout habitat.