A group of scientists recently conducted a study that links higher steelhead death rates to low water levels and the amount of vineyard acreage upstream. In the late summer and early fall of dry years, when water is at a premium not only for irrigation but also to encase the vines in ice during a unexpected freeze, steelhead can suffer up to a 70 percent mortality rate.
“This is the first scientific publication on how vineyards and summer stream flows relate to fish survivorship in California’s tributary streams,” said study principal investigator Adina Merenlender, cooperative extension specialist in UC Berkeley’s Department of Environmental Science, Policy and Management (ESPM). “It is the closest we have to substantiating claims by resource agencies and environmental organizations that juvenile salmon are being impacted by low flows during the summer and survive better with more flow.”
For those wine-loving anglers that feel the need to decide allegiances, fret not, for scientists say that by tweaking water management the two should be able to live in harmony. “I believe we can protect flows for fish and still have our glass of wine,” says Theodore Grantham, a recent Ph.D. graduate of ESPM.