RAS

Tilapia grows faster and use feed more efficiently in seawater recirculating systems than in freshwater

EEUU, 29 August 2025 | University of Hawai‘i at Mānoa study validates the potential of the new TAREC facility

RAS facilities - University Hawai'iCredit: University of Hawaii at Manoa

A team of scientists from the University of Hawai‘i at Mānoa has tested the performance of Mozambique tilapia (Oreochromis mossambicus) in the new Tuahine Aquaculture Research and Education Center (TAREC), a state-of-the-art recirculating aquaculture facility designed for research, teaching and extension.

The study compared fish growth and feed efficiency in two different environments: freshwater (FW) and artificial seawater (ASW) recirculating aquaculture systems (RAS). Over a three-month trial, the researchers observed that tilapia raised in ASW consistently grew faster and achieved a lower feed conversion ratio (FCR) than those kept in FW. In other words, the fish used feed more efficiently when cultured in seawater.

As expected, male tilapia outperformed females in both systems, showing higher growth rates – a pattern widely recognised in commercial tilapia farming. Importantly, the fish tolerated shifts in salinity well, without signs of physiological stress. Water quality in both systems remained far below known toxicity thresholds for tilapia, confirming that the new tanks provide safe and stable conditions for experimentation.

The choice of Mozambique tilapia is not accidental. The species has a long history in Hawai‘i, having been farmed for generations in loko i‘a, the islands’ traditional fishponds. Today, tilapia continue to play an important role in local food security and are widely used in research thanks to their adaptability and market acceptance.

According to the authors, the trials confirm that the new centre can serve as a reliable platform to explore key areas of aquaculture science, including fish health, nutrition, water quality, system design, and stress physiology. The findings also demonstrate the potential of the facility to support training and outreach activities for students, industry and the wider community.

Reference:
Barton, R. L., Toyomura, B., & Tamaru, C. S. (2023). Evaluation of a novel recirculating aquaculture center for research, education, and extension at the University of Hawai‘i at Mānoa. Aquaculture Research. https://doi.org/10.1111/are.16674

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