What’s in it for steelhead & salmon?
With inherent abilities to cope with feast-or-famine climatic and weather extremes, steelhead (Oncorhynchus mykiss ssp. irideus) seem emblematic of California’s “spirit of place”.
Steelhead adaptability can be inspirational to us all.
Anadromous species, steelhead might be considered “ambassadors” to the Pacific, recycling pelagic nutrients whose origins may have been North America, or perhaps any continent – since oceans are globally interconnected mixing zones.
Pacific salmonids’ remarkable homing abilities ensure their evolutionary adaptation to environmental variations particular to given regions. (Boughton 2010)
They travel among aquatic worlds, through fresh, marine waters and variations between, adapting their physiology to local environmental conditions.
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Steelhead exhibit a diversity of life history patterns that also spreads their survival odds across diverse environmental possibilities.
Young steelhead may migrate downstream from headwater spawning grounds early in their life cycle to estuary mixing zones, while others remain in upper watershed areas longer before moving downstream. Still others may adopt the resident rainbow trout life cycle, never migrating to the ocean. (Hayes and colleagues 2008)
When intermittent rivers and streams dry up in summer, steelhead can wait out the dry season in residual ponds that most of us wouldn’t guess might support them.
Evidence suggests steelhead genetic heritage can wait out various human interferences – for periods of time unknown. But population evidence and the “known unknowns” have precipitated due concern.
There was only so much steelhead adaptability could cope with, pitted against our relatively rapid historical human impacts on their survival needs. California steelhead populations have strikingly diminished over decades of waiting, bringing them to threatened and endangered status.
Striking when compared with photos of enormous steelhead caught in great numbers by fishers during the early 20th Century.
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The Rainfall to Groundwater approach was inspired by insights from correlating “factors affecting abundance/persistence” of California central and south central coast steelhead populations (Titus and colleagues 1999) with the nature of land cover in watersheds supporting those populations (Jigour 2011).
“Access impaired in main stem” (Titus and colleagues 1999) was the primary factor addressed in Watershed Restoration for Baseflow Augmentation, Verna Jigour’s doctoral dissertation, finalized in 2011, though benefits addressing some other factors will also accrue from this approach.
Baseflow is the benchmark for supporting anadromous species habitat connectivity. Once spring runoff has ended, groundwater maintains baseflows supporting late spring steelhead migration and persistence through the dry season in our California watersheds.
How may we best sustain baseflows supporting steelhead habitat connectivity? Ponce (1989a) and Ponce and Lindquist (1990a,b,c) [see Citations page] offer a global view of “Baseflow augmentation by streambank storage”. Essentially, we need to restore and epand riparian zones because the root zones and soil ecosystems serve as “sponge” detaining spring flows late into the dry season.
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Kondolf and colleagues (1987) documented the ability of bank storage to sustain flows on the Carmel River “during May and June, months of critical importance to the downstream migration of steelhead trout smolts (Kelley et al. 1982) and probably to the success of willow seedlings” (Kondolf and colleagues 1987). Those willows are part of the riparian ecosystem – the “sponge” of detention storage – supporting baseflow augmentation.
Carmel River is freer flowing following removal of San Clemente Dam, completed 2015. Winter 2016-17 provided potent natural habitat restructuring, setting steelhead habitat recovery on a positive trajectory without humans needing to micromanage the evolution of habitat complexity (Carey 2017). Other supportive efforts have been ongoing and continue along Carmel River.
But not all Central Coast steelhead streams are so fortunate. [And even the Carmel River population still faces challenges.]
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The Salinas River stands out for being California’s third longest river flowing solely within the state, as well as for flowing northwest, parallel to coastline, past the Santa Lucia Mountains before disgorging above the deep Monterey Bay marine canyon, earning it the nickname of “upside down” river (Fisher 1945) .
The Salinas watershed, including the remnants of its historic estuary, may host three unique steelhead populations (Boughton and colleagues 2006) engendered by the challenging inland environment. Evolution of the tenacity required to navigate the alluvial Salinas River to suitable habitat would seem to offer evolutionary advantage supporting the entire South Central Coast Distinct Population Segment (DPS), whose other members occupy mostly coastal watersheds.
Many strategies have the potential to release both the adaptive capacity of steelhead and the sustainability of hydrological services for people. . . . Existing natural capital, such as groundwater storage basins or reconnected floodplains, can potentially support sustainable hydrological services with low construction and maintenance costs.
Lowest cost, greatest potential efficacy of all is watershed/ catchment restoration, as proposed by Rainfall to Groundwater.
This strategy holds particularly potent promise for the Salinas River, given the vast area of annual rangelands in its upper watershed. especially Furthermore, the tributaries fed by those rangelands have historically been considered useless for water resources so they remain free of major dams. Restoration of catchment functions in these rangeland watersheds can feed directly to system groundwater, supporting baseflows that support steelhead migration downstream.
Applying this concept throughout the state should provide support to chinook salmon (Oncorhynchus tshawytscha), as well as steelhead populations.
Boughton, D. A., Adams, P., Anderson, E., Fusaro, C., Keller, E. A., Kelley, E., Lentsch, L., Nielsen, J., Perry, K., Regan, H. M., Smith, J. J., Swift, C., Thompson, L., and Watson, F. 2006. Steelhead of the South-Central/ Southern California coast: Population characterization for recovery planning. NOAA Technical Memorandum NMFS-SWFSC 394.
Boughton, David A. 2010. A forward-looking scientific frame of reference for steelhead recovery on the south-central and southern California coast. U.S. Department of Commerce, NOAA Technical Memorandum NMFS, NOAA-TM-NMFS-SWFSC-466, 46 p. https://swfsc.noaa.gov/publications/TM/SWFSC/NOAA-TM-NMFS-SWFSC-466.pdf
Carey, T. L. 2017. With San Clemente Dam gone, are steelhead trout about to make comeback on the Carmel River? Mercury News. July 7, 2017. http://www.mercurynews.com/2017/07/07/with-san-clemente-dam-gone-are-steelhead-trout-about-to-make-comeback-on-the-carmel-river/
Fisher, Anne B. 1945. The Salinas: Upside Down River. Rivers of America Series, Hervey Allen, Series Editor. Valley Publishers. Fresno, CA.
Hayes, S. A., M. H. Bond, C. V. Hanson, E. V. Freund, J. J. Smith, E. C. Anderson, A. J. Ammann, R. B. MacFarlane. 2008. Steelhead growth in a small central California watershed: upstream and estuarine rearing patterns. Transactions of the American Fisheries Society 137:114–128. DOI: 10.1577/T07-043.1
Jigour, V. J. 2011. Watershed Restoration for Baseflow Augmentation. Doctoral dissertation. Interdisciplinary Arts and Sciences: Conservation Ecology. Union Institute and University.
Kondolf, G. M., L. M. Maloney, and J. G. Williams. 1987. Effects of bank storage and well pumping on baseflow, Carmel River, Monterey County, California. Journal of Hydrology 91:351-369.
Titus, R. G., D. C. Erman, and W. M. Snider. 1999 in preparation (draft manuscript). History and status of steelhead in California coastal drainages south of San Francisco Bay. California Department of Fish and Game, Sacramento, California, USA.