Js. Meyer et al., Relationships between boron concentrations and trout in the Firehole River, Wyoming - Historical information and preliminary results of a field study, BIOL TR EL, 66(1-3), 1998, pp. 167-184
The Firehole River (FHR) in Yellowstone National Park (YNP) is a world-reno
wned recreational fishery that predominantly includes rainbow trout (RBT, O
ncorhynchus mykiss) and brown trout (BNT, Salmo trutta). The trout populati
ons apparently are closed to immigration and have been self-sustaining sinc
e 1955. Inputs from hot springs and geysers increase the temperature and mi
neral content of the water, including elevating the boron (B) concentration
s to a maximum of similar to 1 mg B/L. Both RBT and BNT reside in warm-wate
r reaches, except when the water is extremely warm (greater than or equal t
o similar to 25 degrees C) during midsummer. They spawn in late fall and ea
rly winter, with documented spawning of BNT in the cold-water reach upstrea
m from the Upper Geyser Basin and of RBT in the Lower Geyser Basin reach, w
here water temperatures presumably are the warmest; however, successful rec
ruitment of RBT in waters containing similar to 1 mg B/L has not been demon
strated conclusively. Thus, we began investigating the relationships among
temperature, B concentrations, other water-quality parameters, and the dist
ribution and reproduction of trout in the FHR in spring 1997. However, atyp
ical high water flows and concomitant lower than historical temperatures an
d B concentrations during summer 1997 preclude conclusions about avoidance
of high B concentrations.