Sunday, July 18, 2010
Lethal Water Temperatures
Optimal water conditions for one species of fish may not be suitable for another. This is the situation making it possible for summer Steelhead and Bass to coincide on the John Day River under normal water conditions.
One of the first questions people ask me on Bass fishing trips is, “do the Bass eat the Steelhead?” Steelhead smolts on the John Day River migrate to the ocean in the spring when water temperatures are cold and high. Bass are dormant at this time giving the smolts a very high probability of migrating to the ocean without being consumed by the Bass.
The second question is, “are Steelhead present at this time.” My answer is, “Usually not because the water temperature is currently lethal to anadromous fish."
This year with high spring runoff, a cooler spring, and already record numbers of Steelhead coming over Bonniville Dam, the early returning Steelhead have been enticed to enter the river.
For the last 8 years Marty and I have guided on the John Day for Bass, usually by July first the water temperature is already in the seventies (73 to 78 degrees) and the CFS (cubic feet per a second) is around 500cfs, this making it great conditions for Bass fishing and lethal conditions for a returning Steelhead.
Completed in May, the University of Idaho College of Natural Resources report, "Temperature regimes during upstream migration and the use of thermal refugia by adult salmon and steelhead in the Columbia River basin," describes how these fish are seeking out cool spots along their journey, and the potential consequences of warming water temperatures on their ability to survive and spawn.
Authored by Matthew Keefer and Chris Caudill (fisheries scientists with the University of Idaho), and Chris Peery (U.S. Fish & Wildlife Service fisheries biologist), the report states that water temperatures in the 19-22 degrees C range, like those that routinely occur in the Columbia River mainstem, are thought to be stressful for adult migrants. The impacts of higher temperatures on the migrating fish create changes in behaviour, and affect disease susceptibility, reproductive development, gamete quality (i.e., over-ripening), survival and fitness.
Marty and I are not authorities on thermal beariers to fish but believe the majority of John Day summer Steelhead that return, linger in the John Day arm, waiting for the cfs to rise and water temp to drop before entering the system.
The last 6 days I was on the river I saw two, wild, dead, Steelhead. Marty has seen three fish; two, dead, wild Steelhead and one that was still alive with its nose up to a cold spring. He said the fish was chrome from the nose to mid body then brown from mid body to the tail. These where not last year’s fish.
This so very sad to see.
Currently DEQ is seeking comments on draft documents describing pollution limits and plans to improve water quality in the John Day Basin.
The federal Clean Water Act requires Oregon to develop plans that include pollution control targets for improving water quality in impaired water bodies. DEQ is doing this by establishing limits known as total daily maximum loads (TMDLs) for temperature, bacteria, dissolved oxygen and biological criteria in the John Day Basin. TMDLs determine the amount of pollution that rivers and streams can assimilate while meeting clean water standards. The TMDLs also include a Water Quality Management Plan that calls for improvements, to be carried out by various branches of state, local and federal government.
The TMDL document can be accessed from the DEQ website: http://www.deq.state.or.us/WQ/TMDLs/johnday.htm. In addition, paper copies and CDs are available by request, and have been placed at the Gilliam County Library, the Grant County Library and the North Fork Watershed Council Office.
DEQ is accepting public comments that extends from June 8, 2010 through August 9, 2010. Please let them know that is unacceptable for wild fish.
DEQ welcomes any input you might have during this comment period, Please feel free to call Don if you have any additional questions.
Don Butcher Basin Coordinator
Oregon Department of Environmental Quality
700 SE Emigrant
Pendleton, OR 97801
(541) 278-4603
(541) 278-4603