12/5/2012: Rain, Rain, Rain
Conservation biologist Jon Rosenfield responds to news about unusual salmon sightings in a Stockton drainage canal.
Dr. Jon Rosenfield is a conservation biologist who represents The Bay Institute in various planning efforts to protect and restore the San Francisco Estuary and its watershed, including its numerous endangered species.
December 5, 2012
Rain, Rain, Rain! Nothing makes an aquatic biologist happier, especially one who lives in dry climates, than rain. And rain makes fish happy too. Most of our Bay's unique and economically valuable fish species respond positively to improved freshwater flow conditions in the estuary and the rivers that feed it.
So it is with Chinook (a.k.a. king) salmon. It's a simple rule on the Pacific coast of northern North America: where freshwater flows unimpeded to the ocean, wild Chinook salmon will migrate and attempt to spawn. A recent article in a Stockton paper documenting the discovery of two Chinook salmon in "an overlooked drainage canal in the middle of a busy city" is the latest evidence of that maxim.
Columnist Michael Fitzgerald writes:
"High flows of stormwater flushing out of the city system evidently created an 'attraction [flow] that confused the salmon," said Kari Burr, a fisheries biologist with the Fishery Foundation of California.
Burr had good news and bad news. The thwarted salmon will seek spawning ground in the canal and die. Even if they managed to spawn, their progeny will not escape the drying creek.
On the bright side, "It just lets us know how many fish are in the system right now for this to be happening," Burr said.
The presence of salmon in the ditches highlights the tremendous potential to restore this tenacious (and tasty) fish to its former home in the San Joaquin River valley. But the appearance of salmon in this atypical location does not mean that Central Valley salmon populations are healthy and stable. In fact, salmon from the SJR basin and other wild spawning populations in the Central Valley are far from the doubling standards mandated in federal and state laws. And, the typical locations preferred by salmon are cut off by dams, inadequate or reverse flows, and salty runoff that confuses migrating fish.