Earlier this week, the California Department of Fish and Game reported that the Spring 2010 survey for delta smelt (the 20mm survey index) resulted in the highest number counted in the past four years. This relative abundance index (here’s the memo from DFG) provides some evidence that the downward trend in delta smelt abundance that we’ve seen for the last several years – a trend experienced by several different fish species that depend on a healthy Delta – may be reversing. We’ve heard that the results of another survey by DFG (the Summer Townet Index) also show a small increase, to the highest level since 2004, but to my knowledge those results have not yet been publicly released by DFG.
These survey results give us some cautious optimism that environmental protections in the Delta are beginning to work to reverse the decline of delta smelt. That said, Delta smelt populations are still at extremely low levels, and there’s still a very high risk that the species could go extinct. It is going to take time and much more work to restore an ecosystem as heavily battered as the Delta; as the National Research Council concluded, “[r]eversing or even slowing the declines of the listed species cannot be accomplished immediately.”
So there’s still a long way to go, not only for delta smelt, but for all the critters in the Delta, from the tiny crabs and plankton to magnificent Chinook salmon and steelhead. But it's a bit of good news, and we hope it's a sign of better years to come for the Delta, and for the fishing communities and jobs that depend on the Delta's health.