Location: Fraser Valley,
Chilliwack River, Center Creek, Foley Creek, Statlu Creek, Coquihalla River and Silverhope Creek
Project Summary
SUMMARY
To compensate for low ocean survival, low salmon escapement, and other freshwater habitat impacts, slow-release fertilizer will be applied in 6 Fraser Valley streams, with subsequent water chemistry, periphyton, and juvenile size-at-age monitoring, to enhance primary productivity, improve freshwater overwinter survival, and increase ocean survival for fish with long stream residency periods.
DESCRIPTION
Salmonid species spend the largest portion of their adult life developing in salt water environments before returning to their natal freshwater streams to spawn and die. This life cycle provides an ecologically important process of delivering marine-derived nutrients (MDN) to freshwater aquatic and terrestrial ecosystems, providing links between ecosystems, playing a critical role in maintaining ecosystem health, and having significant implications for conservation and biodiversity of freshwater flora and fauna.
The number of salmonids returning to spawn (escapement) has declined due to recent downturns in ocean survival (Stockner 2000, Ward 2000), and anthropogenic freshwater habitat impacts have further reduced freshwater ecosystem productivity (Larkin and Slaney 1997). The importances of MDN have been well studied (Kline et al. 1990, Bilby et al. 1996); reduced salmon escapement reduces this ‘nutrient pump’ which has implications on the production of the whole ecosystem. Many anadromous streams in the Pacific Northwest are classified as oligotrophic (nitrogen and phosphorous deficient) and even ultra-oligotrophic (Stockner 2003). These key macronutrients limit the food available to fish in streams and rivers; they are required for the growth of algae that aquatic insects feed on, which are then fed upon by fish (Quamme and Slaney 2003).
Stream nutrient enrichment, through the application of slow-release phosphorous fertilizer throughout the summer growing months (June to September), has been shown to augment the nutrient cycle benefiting lower trophic levels first which is then relayed up the food chain and is one of the most effective and cost-efficient restoration/recovery tools available for rearing/freshwater fishes. Enhancing fish rearing conditions is related to increased fish growth and health (size and condition) and improved over-winter survival while also increasing smolt production (Ward et al. 2006), marine survival and ultimately escapement. The project is aimed at the conservation and recovery of wild salmonid and resident fish stocks and increasing angling opportunities, with significant benefits to other aquatic and terrestrial freshwater ecosystem species from restored watershed processes.
An innovative and clean new fertilizer product will be used; fertilizer recovered (recycled) from waste water (Britton et al. 2005) will be used to enrich 5 priority streams in the Lower Mainland, while the Chilliwack River will be enriched with liquid fertilizer. Work will be coordinated by BCCF fisheries biologists and technicians under the direction and supervision of BC Ministry of Natural Resource Operations biologists with significant volunteer assistance from a variety of stewardship and angling groups. The total project costs $70,000 of which $18,000 is being requested through this application.
OBJECTIVES
Increase phosphorous and nitrogen concentrations to compensate for low levels of marine-derived nutrients (salmon escapement) in freshwater habitats
Increase algal growth and subsequently improve fish health (length and weight) to offset poor freshwater habitat conditions and low ocean survival
Increase watershed awareness and educate on the importance of nutrients in freshwater ecosystems
METHODS
Fertilizer Type
Crystal Green¨ fertilizer (5-28-0) recovered from waste water treatment plants (Britton et al. 2005) will be used to fertilize key rearing tributaries. This small, solid, slow-release fertilizer is efficient in terms of attaining target concentrations in small to mid-sized streams while being easy to apply and monitor (Reddekopp et al. 2006). Extensive testing by MoE, Ostara and BCCF have shown that Crystal Green¨ contains negligible levels of heavy metals which are significantly lower than that found in competing commercial fertilizers, and contains no organic contaminants (Wilson et al. 2009. Contaminant Testing of Struvite, Prior to Application as a Stream Fertilizer. Nov 2009 draft document; BC MoE, data on file). Agricultural liquid fertilizer, ammonia polyphosphate (10-34-0), is most appropriate for applications to areas with large flows (Ashley and Stockner 2003) and will be applied on the Chilliwack River using an automated drip station located in a secure location on private property, downstream of domestic water license use.
Fertilizer Application
Historic discharge data (Water Survey Canada, BC Hydro, and raw data on file) are used to calculate specific target nutrient loading rates (i.e. 5.0 ug/L orthophosphate), with further adjustments made using snow pack accumulation estimates (River Forecast Centre), weather forecasts, and field flow measurements. Following the freshet in late-spring or early-summer, biodegradable burlap bags are filled with 10 kg of solid fertilizer and placed instream with the assistance of volunteers. Large rocks are placed on each bag ensuring that the fertilizer is not flushed downstream in the event of higher streams flows. Additional fine-tuning of loading rates, up or down, occurs as the water levels subside to mean summer flows by either relocating the burlap bags further into the receding streams or by removing some of the bags. Site selection and application techniques are consistent with guidelines as described in Ashley and Stockner (2003) and McCusker et al. (2002).
Monitoring
Prior to field application of the fertilizer, samples of the fertilizer will be sent to the lab for an analysis of a number of chemical parameters including heavy metals and other contaminants. Stream water samples are taken prior to fertilizer application and are taken bi-weekly throughout the summer growing period into early fall. Samples taken upstream and at specific distances downstream of the fertilizer placement are sent to the Pacific Environmental Science Centre for low-level nitrogen and phosphorous analysis. Periphyton plates, artificial foam substrates secured to concrete paving stones, will be placed in control and treated sections of the rivers. Core samples will be taken bi-weekly, simultaneously with the water samples, and sent to Maxxam Analytics Inc. to assess algal growth (chlorophyll a) throughout the growing season (June to September). In addition to periphyton and water chemistry sampling, stream temperatures, flow measurements and visual observations of algal growth and insect abundance will be monitored and the fertilizer bags routinely inspected to optimize location and release rate.
Juvenile Fish Assessment
Juvenile fish assessment will occur in early fall utilizing electro-fishing techniques in accordance with government fish collection protocol. In each treated and control site, a minimum of 30 juvenile fish from each age class (fry and parr) will be captured, measured (fork length) and weighed. Scale samples will be obtained from a subset of the fish captured and scale ageing will determine weight- and length-at-age used to compare fish size in treated vs. control sections. Comparing fish size-at-age data is used in place of smolt yield studies as the latter demands a much greater level of labour and funding. This approach follows recommendations from the Effectiveness Monitoring Guide for Stream Restoration Conducted for Greater Georgia Basin Steelhead Recovery (Slaney 2006); and is integrated with the work on Vancouver Island.
Other Project Details
BC Conservation Foundation fisheries staff will work as closely as possible with BC Ministry of Environment (and/or operational staff in the new BC Ministry of Natural Resource Operations) regional staff and will be responsible for partnering with First Nation, local community, angling and stewardship groups in enrichment activities and providing equipment and technical support to volunteers. Volunteers from the Kingfishers Rod and Gun Club, BC Federation of Fly Fishers, Steelhead Society of BC, Chehalis First Nation, Ch-ihl-kway-uhk First Nation students, Chilliwack River Action Committee, Chilliwack Fish and Game Protective Association, Fraser Valley Conservancy, South Coast Steelhead Coalition, Mission Off-Road Club, and local fish and game clubs have been and continue to be active in nutrient applications, and will be invited to participate again.
BENEFITS
Protection and restoration of sensitive natural areas:
5 of the 6 priority streams are classified as wild streams and they have been historically impacted by a variety of activities including logging to the streambanks and erosion-control measures. Stream enrichment imitates natural nutrient cycling by providing key macronutrients to freshwater ecosystems. Aquatic species benefit the most while nutrients are delivered to terrestrial freshwater ecosystems through birds and mammals feeding on salmon carcasses. Carbon, nitrogen and phosphorous nutrients stimulate plant growth and encourage re-vegetation of impacted riparian zones which stabilize streambanks and restore vital watershed processes.
Community-based watershed stewardship:
This project supports stewardship groups in repeating and/or undertaking new stream enrichment initiatives based on an easily replicated project methodology and available technical guidance from BCCF.
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