The 2013 effort to show support for stronger, science-based protections for coho critical habitat in Marin County is again supported by leading scientists Dr. Sylvia Earle, Dr. Peter Moyle, and Dr. John McCosker!
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SCIENTIST OPEN LETTER TO MARIN COUNTY BOARD OF SUPERVISORS
Wild coho salmon populations in California have undergone a ninety-percent decline since the 1940s. The causes of this decline, such as urbanization, dams, and logging operations are well known and documented. Central California Coast (CCC) coho salmon were listed by the US government as Threatened in 1997 and uplisted to Endangered status in 2005 The State of California listed the population north of San Francisco as endangered in 2002. In short, coho salmon are in danger of extinction throughout coastal California. Because of this, the Lagunitas Creek watershed is exceptionally important for its survival; it is one of the few watersheds that still supports a self-sustaining population of this iconic fish.
The Lagunitas Creek Watershed is listed as "critical habitat" for coho under the Endangered Species Act. As scientists concerned with the health and recovery of salmonid populations throughout California, we support increased habitat protections for coho in the Lagunitas Creek Watershed, which makes up approximately 10-20% of the total current population of CCC coho salmon.
Lands in the lower reaches of the Lagunitas Creek watershed are relatively well protected (and include State Parks, National Parks and Recreation Areas, and County and Water District property) and maintain habitat values important to coho and other native species. But, 30-50 percent of spawning in the Lagunitas Creek Watershed occurs in the undammed headwaters of the tiny (10 square mile) San Geronimo Valley. Out-migration research has documented that as much of 1/3 of Lagunitas Creek coho rear in these headwater reaches annually.
Marin County's San Geronimo Valley Existing Conditions Report (2009), prepared by Stillwater Sciences1 as part of a Salmon Enhancement Plan, documented the percentage of impervious surface for seven reaches of Geronimo Creek at 7.3-20.8 per percent, with four of the reaches exceeding 15 percent. Furthermore, this study conducted detailed analysis on 17 parcels and demonstrated the limited amount of riparian habitat currently extant in this watershed: ten parcels had no intact riparian habitat, four had a width of less than 22 feet, and the remaining three had a width of 30, 36 and 92 feet (summarized in Table A2.2 of the report). This data demonstrates the relatively high level of urbanization that already threatens the survival of coho here.
The San Geronimo Valley continues to urbanize with new housing development trending toward larger houses, and development on existing parcels expanding with building additions and additional loss of riparian habitat. This affects coho salmon survival because the juveniles need cold clear streams with lots of riparian trees and in-stream woody debris for cover and minimal disturbance. Loss of current and potential riparian habitat and floodplains to development poses significant additional threats to the survival of coho here.
We appreciate that Marin County Supervisors are now considering a new Stream Conservation Ordinance. While the Marin County General Plan calls for no net loss of habitat, the current draft ordinance fails to come close to meeting this goal.
WE THE UNDERSIGNED, CALL ON MARIN COUNTY SUPERVISORS TO ENACT A STRONG ORDINANCE THAT INCLUDES THE FOLLOWING PROVISIONS THAT WILL HELP TO RESTORE COHO POPULATIONS:
1. Any development within 100-foot setback from creeks should be strongly discouraged. New development in this buffer that is allowed should require mitigation if new structures or activities reduce the potential for rehabilitation of riparian habitat, even if it is currently disturbed by lawns, patios, etc. A 2:1 or higher mitigation ratio is recommended to improve on current conditions that already include a significant loss of riparian habitat.
2. Ephemeral Tributaries to Salmon Streams should be protected with a 100-foot setback. Presently, the draft ordinance only provides for the 100-foot setback if 100 feet of "continuous" riparian vegetation is present, basically exempting a large percentage of important habitat, thus decreasing stream habitat for juvenile coho. We see no scientific basis for limiting protection only to ephemeral streams with "100 feet of continuous riparian vegetation." A functioning network of ephemeral streams mitigates flooding and forms the headwaters without which mainstems could not support salmon.
We realize that these requested ordinances will inconvenience landowners, but without them, development in the Geronimo Valley will likely lead to extirpation of coho salmon from the watershed, making the recovery of coho salmon in the Lagunitas Creek watershed increasingly problematical. The result will be further decline of coho salmon in California. The recovery of coho salmon as a viable species in California will only happen as the result of many small positive actions on many streams, especially by landowners who have chosen to live in coho watersheds. The proposed ordinances will provide significant help to one of the most important coho populations left. We would like to see Marin County be a leader in coho salmon conservation, rather than just one more example of local government failing to protect local resources.
(partial sign-on list below)
Peter Moyle, PhD
John McCosker, PhD
Sylvia Earle, PhD
Bruce MacFarlane, PhD
Leo Salas, PhD
Tierney Thys, PhD
Bruce Baldwin, PhD
Joseph Cech Jr. PhD
Judith Innes, PhD
Sarah Frias Torres, PhD
Bruce Baldwin, PhD
Chris Pincetich, PhD
Jacob Katz, PhD
Judith Innes, PhD
David DeSante, PhD