Dissolved gas levels in the Columbia River caused by spill decreased
slightly in 1998, the National Marine Fisheries Service reports.
The decrease is attributed to lower precipitation compared to 1996 and
1997, and to modifications of spillways at Ice Harbor and John Day dams.
Biological monitoring found few signs of gas bubble disease in fish throughout
the year.
NMFS summarized total dissolved gas supersaturation (TDGS) data in a
report on its 1998 spill program submitted last month