Project Scale:
50 tonne annual production Atlantic Salmon smolt (Cell 1)
42 tonne continuous standing biomass of White Sturgeon adults (Cell 2)

Where:
Sechelt, BC, Canada

When:
The first cell was constructed in 1999 and the second followed in 2001.

Project Description:
The salmon smolt production facility at Gray Creek Hatchery was at the time, Western Canada’s largest commercial scale recirculating aquaculture system.

The follow-up project became the first Canadian commercial scale recirculation facility for culturing white sturgeon.

Services Provided:
Turn-key facility design, equipment supply, and construction management services. At design completion, PR Aqua prepared operating manuals and provided training to operations staff. In the years since operation began, PR Aqua has provided water quality troubleshooting services and advice when required.

Project Features:
Each of the two recirculating aquaculture systems at Gray Creek Hatchery feature “state-of-the-art” filtration system designs which allow for recirculation of up to 98% of the culture system flow rate of 570 m3/hr (2500 gpm). The design adheres closely to the designs developed at the Freshwater Institute in West Virginia by some of the industries leading researchers.

The primary reasons for water recirculation included optimization of a limited water resource and the reduction of costs associated with heating energy.

The design incorporates Cornell-style dual drain tank designs, swirl separators and micro-screen drum filters for solids filtration, fluidized sand bed biofilters for ammonia removal, carbon dioxide stripping, pure oxygen addition, and full flow ozonation. Each cell is enclosed in a pre-engineered dual walled greenhouse structure.

As risk management was of great concern, the potential for mechanical and electrical failures was addressed through designed equipment and power supply redundancy.

Challenges and Solutions:
During development of Cell 1, a long term facility plan was developed to allow for future expansion. Site preparation, access, and utilities were designed to incorporate up to four recirculation cells.

Cell 2 was designed for salmon smolt rearing at cold water temperatures but, during construction was modified for interim holding of juvenile sturgeon, at warm water temperatures, pending the construction of a larger sturgeon grow-out facility. Delay in construction of the grow-out facility has resulted in the continuous, long-term holding of adult sturgeon at much higher temperatures and densities than anticipated at time of design. The robust and flexible facility design has provided continued success despite evolving, and widely varying, production requirements.

Results:
The facilities have consistently exceeded the expectations of Target Marine Products, both in terms of biomass carrying capacity and feed load, while maintaining superior water quality.