Thursday, May 20, 2010

Big Hole Watershed Committee: Killing Grayling, Again

Today's Grayling Survival Index = -37.5. An index of "zero" marks the minimum sustainability point. Below that, recruitment and survival are likely to be so low that the population is in decline. Montana's Big Hole River is home to a rapidly declining population of fluvial Arctic grayling--the last such population in the lower 48 states.

Despite wet, cool spring weather, Big Hole ranchers in the upper river basin (from Wisdom upstream) are seriouly dewatering the river. Hay fields are flooded while fish die. Current flows at Wisdom are hovering between 40 and 50 cubic feet per second (cfs). This is well below the lower wetted perimeter of 60 cfs--the level at which the carrying capacity of the river channel habitat rapidly falls off. It is FAR, FAR below the upper wetted perimeter of 160 cfs--the level at which carrying capacity is optimal, and the level which is a desirable target for spring flows.

May is a critical time period for the spawning and recruitment of grayling. Without optimal flows during this time, an entire age-class of fish can be lost.

The Big Hole Watershed Committee has a so-called "Drought Management Plan." Given the extra-ordinary low flows for this time of year, why has the Committee not implemented this Plan? Does the Committee actually desire to exterminate the few remaining grayling before the U.S. Fish & Wildlife Service can impose Endangered Species status?

Furthermore, where are "conservation" groups such as the George Grant Chapter of Trout Unlimited and the Big Hole River Foundation in this process? Though the Watershed Committee is dominated by agricultural interests, the participation of TU and the Foundation legitimates the destruction of Big Hole River grayling.

Support groups such as the Center for Biological Diversity--instead of fiddling while Rome burns, the Center is doing everything it can to stop this madness.


Definition of the Grayling Survival Index.