Overcoming Barriers to Support the Growth of Land-based Atlantic salmon Production in the Great Lakes Region
Funded By: NOAA's National Sea Grant College Program
Land-based closed containment salmonid production represents an important and growing sector of the overall aquaculture industry. Land-based, closed containment fish farm operations utilizing water recirculation aquaculture system (RAS) technologies offer the industry a viable and sustainable means to expand domestic production, while capitalizing on the numerous benefits to this approach, including: enhanced biosecurity, a high degree of control over the fish rearing environment, technologies to effectively capture wastes in order to reduce environmental impact, as well as enforcing no interaction between farmed fish and wild populations. Support for research and technology development is needed to facilitate the growth of this industry sector and is vital to meet U.S. seafood demand. Continued research and development in closed containment aquaculture production will also facilitate domestic agricultural economic contribution, job growth, and food security.
While most of the Atlantic salmon consumed in the U.S. is imported from Chile, the domestic production of Atlantics is mostly confined to a relatively small industry in the states of Maine and Washington. However, land-based production of market size Atlantic salmon is commencing in the Great Lakes region, specifically in Wisconsin in what is currently the largest land-based salmon aquaponics operation in the world (Superior Fresh LLC, Hixton, WI); other land-raised salmon farms are planned in other regions of the country. Based on current knowledge, there are several major technical-biological challenges are encountered when producing market-size Atlantic salmon in land-based systems: (i) reducing early male maturation, (ii) managing saprolegniasis (commonly termed "fungus") during the parr – smolt early life stages, and (iii) ensuring the flavor profile of the harvested fish. Fortunately, current research suggests that use of commercially available all-female Atlantic salmon eggs will avoid problems with early maturation. However, the challenges of saprolegniasis and off-flavor purging still need to be overcome.
To provide industry with timely and relevant recommendations to combat saprolegniasis and to ensure fillet quality, this project will examine these critical areas to reduce or eliminate the current barriers affecting Atlantic salmon production on land.
Effective therapeutic strategies must be developed not only to reduce losses to saprolegniasis but also to maintain adequate water quality for fish health and performance, i.e. to not impact RAS biofiltration capacity. The development of such therapeutic approaches would be highly beneficial to industry, both for RAS smolt production and land-based closed containment growout, and will ultimately enhance the economic viability of RAS operations.This project will evaluate whether saprolegniasis is reduced with the use of peracetic acid and/or hydrogen peroxide treatments during vulnerable fry and smoltification stages while maintaining acceptable fish welfare. Optimal therapeutant dosage range for each specific life-stage will be identified through these experiments.
off-flavor is often rejected and can cause consumers and seafood retailers to
subsequently avoid the product, which can have devastating consequences to the
producer if they cannot readily sell their product. Off-flavor is commonly due to chemical compounds created by the secondary metabolic products of certain species of bacteria, in which the fish primarily uptakes through the gills. These compounds can also be diffused out of the gills upon transfer to a clean water system with lower concentration of the accumulated chemical compound. In
aquaculture, this physiological process serves as an advantageous mechanism for
off-flavor reduction and is referred to as depuration or purging. Currently,
the recommended practice to depurate off-flavor from salmonoids produced in RAS
is to transfer fish to separate, odor-free depuration systems that are flushed
with water in a single pass or are operated with limited water recirculation. This project will investigate whether increasing fish ventilation rates with swimming speeds and oxygen levels can shorten the depuration time, saving substantial time and space in commercial farms.
Research for this project will be conducted at UWSP NADF and at The Conservation Fund's Freshwater Institute, West Virginia. Other project partners include Wisconsin Sea Grant and private industry partners, Superior Fresh, LLC. and Riverence, LLC.
Project also highlighted in WI Sea Grant article...
Photos: Atlantic salmon raised in RAS at UWSP NADF (top). Atlantic salmon fingerlings at UWSP NADF (bottom).