As regular readers know, we recently took our campaign against planter trout in the Mckenzie to the next level with the publication an opinion piece by Matt and Chris in the Register Guard suggesting that it is time to move towards managing the Mckenzie for wild fish.
Most people, myself included (until recently) haven’t realized the full extent of the harm to native fish populations caused by stocking hatchery trout. My research uncovered a 1982 (I believe) paper by E. Richard Vincent of the Montana Department of Fish and Wildlife entitled ‘The Effects of Stocking Catchable-Sized Hatchery Trout on Wild Trout in the Madison River and O’Dell Creek, Montana.’ You don’t have to make it far into the document to be amazed. I think I’ll let Mr. Vincent do the talking:
Fall wild populations of two-year-old and older brown and rainbow trout increased 159% and 868% in number and 160% and 1016% in total biomass respectively, four years after the last catchable-sized hatchery rainbow trout was stocked in the Varney section of the Madison river. Brown trout increases peaked within two years after stocking of catchables had ceased, whereas wild rainbow trout biomass levels were still showing increases four years after the last stocking. Wild brown and rainbow trout between 10.0-17.9 inches showed the greatest increases when stocking ceased.
I can’t stand 17.9 inch trout trout, can you? Meanwhile . . . .
When catchable-sized hatchery trout were stocked for three consecutive years into a previously unstocked section of O’Dell Creek, the number of two-year-old and older wild brown trout population was reduced 49% in total number and biomass. Wild brown trout between 10.0 and 17.9 inches showed significant declines in number after stocking was initiated, whereas those smaller than 10 inches showed no significant change in numbers.
In the most recent assessment of wild trout on the Mckenzie River, 257 of 307 fish tagged were under 10 inches. Hmmm. This sounds consistent with Vincent’s findings. None of this information is unknown to our local fish managers, the Madison River/ O’Dell Creek fieldwork was performed between 1966 and 1972. Meanwhile in 2009 on the Mckenzie we are dumping 140,000 or so eight inch planters into what could be a fantastic fishery.
Could it be that we’ve been stocking the Mckenzie for so long we’ve forgotten what it could be? I think it’s time to find out.–KM