Friday, December 7, 2007

Ventura River Steelhead

Despite the fact that 2007 was the driest year on record, biological surveys this summer revealed the presence of at least two large adult steelhead in the Ventura River. This species was listed as endangered in 1997 by NOAA Fisheries (NMFS), the federal agency charged with management of anadromous fisheries in the United States. (The steelhead run on the Ventura River is estimated to have numbered over 4,000 returning adults prior to the construction of Matilija Dam in 1948. )

The recently released NMFS Southern Steelhead Recovery Plan Outline describes the reasons for population decline. These include the alteration of natural stream flows, physical impediments to fish passage including dams and culverts, stream sedimentation, pollutant discharges into waterways, the spread of non-native species, and the loss of river estuary habitat. Priority actions for recovery include the removal of Matilija Dam and similar impediments to restore free passage to and from the headwaters. Apart from fish passage, perhaps the most important action is to restore natural stream flows.

THREATS: The presence of these two fish in the lower Ventura River is particularly significant as the City of Ventura seeks to increase its water supply to fuel projected growth. Currently approximately 2/3 of the city's water comes from the Ventura River, and there are two projects underway that would potentially increase this amount. 1) Foster Park Wells - upgrade of this facility would potentially double the pumping capacity to match the increased capacity at the Avenue Treatment Plant. 2) Ojai Sanitary Effluent Reuse - a study released this summer suggested that one half of the treated sewage currently discharged into the lower river could be reused, potentially providing an additional 1000 acre-feet per year. The same study noted that in dry years (like 2007) this effluent makes up 80% to 100% of the flow in the lower river.

Meanwhile, reports of fish kills have become common in recent years. This past summer, reports confirmed the deaths of 11 juvenile steelhead below the Robles Diversion Dam. A similar event was documented in March 2006 when a popular swimming hole dried up a short distance downstream of the diversion.
It is important to note, however, that there remains a population of resident native trout in the perennial creeks found in the upper watershed. This habitat was documented as part of the Matilija Dam Ecosystem Restoration Feasibility Study and may be found at the bottom of the reports page:

It's the little guys like this one that provide the potential for recovery of the species. Steelhead differ from salmon in that they do not have to become anadronmous. But some of the offspring from these resident native trout may decide to head for the ocean, and those that make it may return like the 22"-25" fish sighted by biologists this year.