Today we were out testing a new survey method on a reach of a stream that we typically survey via electrofishing. Snorkel surveys basically consist of putting on a wetsuit (16 degree Celsius water is cold for us warm blooded critters), grabbing a snorkel and an underwater flashlight and poking into the pools to identify and count the inhabitants. It is a much less invasive survey method than electrofishing, in which an electrified probe is stuck into the water that shocks the fish so that they can be netted, measured and weighed. The fish are returned to the water afterward, but when we’re working with already stressed populations we like to use a less invasive alternative. This particular stream has totally dried up in sections for several years in a row due to the drought, so the fish have no choice but to oversummer in the remaining pools. So far, the pools have been expansive enough and the water cool enough that we have not lost our populations of native trout (Oncorhyncus mykiss) and California newt (Taricha torosa). But there is great concern for the viability of the populations.
A popular hiking trail runs right alongside this creek, and despite signage asking folks to keep their pets out of the water, dogs are constantly jumping in and disturbing the critical oversummering pools. These fish are evolved to endure prolonged drought, hunkered down in the oversummering pools. What they are not evolved to endure is dozens of dogs invading and disrupting their pools day after day throughout the dry season and causing water turbidity to go through the roof. Turbidity lowers dissolved oxygen (DO) content, making it more difficult for critters with gills to breathe. So, when we started our annual population surveys, we decided not to electrofish to avoid adding another stressor to these already stressed populations.
The survey was hearteningly successful, and the pools fairly ample and deep throughout the reach. But this is due to a surprising cause. There is a golf course upstream of this reach that, due to the watering of the turf, creates an additional groundwater input that augments the streamflow. Who would have thought that golf courses could be beneficial to fish? It’s a fascinating example of reconciliation ecology – anthropogenic (human) activity actually benefiting wildlife instead of harming it. We don’t know for sure, but there is a chance that if this golf course did not exist, we would not have found any viable pools at all. While more a happy accident than a purposeful act of conservation, it is certainly an important factor to be considered when planning species conservation efforts in a watershed heavily impacted by other human activities. In areas where humans have altered natural dynamics so drastically, nature needs all the help it can get.