Inland, indoor brackish water aquaculture is growing in popularity throughout the world, particularly in temperate areas of Europe, Asia, and North America. These aquaculture operations can provide niche products to local markets, typically at high prices. However, these aquaculture systems often accumulate high levels of nitrate and phosphate due to limited water exchange. When water is discharged or exchanged from these systems, the high levels of salt make it unsuitable for fertilizer while the high levels of N and P limit the amount of discharge allowed due to local laws and regulations. Aquaponics may provide producers an avenue to remove N and P through plant production, gaining an additional form of income while retaining valuable salt water. While halophytic and glycophytic plant species have been studied for their suitability in brackish water aquaculture, the management of these plants and the systems they are produced in are different than freshwater.
At Kentucky State University researchers have been investigating the potential of brackish water aquaponics. To date, 18 different plant species have been tested for their tolerance to and performance in varying concentrations of salt water. Furthermore, trials have been conducted that investigate the potential for animal production in plant beds, the effects of high levels of nitrogen on plant performance in a saline environment, enhancing salinity tolerance through the supplementation of different nutrients like iron, and the effects of suspended solids in brackish water on the health and vigor of plant root systems.
Although these trials have shed light on the performance and adaptability of numerous plant species in brackish water, there have been many lessons learned regarding system design and plant husbandry. Pest management of saline-stressed plants, seed germination and plant propagation methods, salt acclimation and accumulation processes, media choices, nutrient availability and manipulation, lighting requirements and water quality testing that work well in freshwater aquaponics have, in many cases, been found to work poorly or fail entirely in brackish water aquaponics. This presentation will cover many of these findings that are not hard data, but more tips and tricks that have resulted in successful brackish water plant production.