Marine finfish aquaculture is dominated by carnivorous species, requiring diets high in proteins and oils, often fulfilled through wild-sourced fish products. Reliance on wild fish resources gives the impression that aquaculture is not sustainable, driving research (including over a decade of work by Kampachi Farms) to identify alternative ingredients and reformulate feeds for 'carnivorous' fish. However, herbivorous marine finfish do not require dietary fishmeal or fish oil, offering a direct means of circumventing these obstacles.
Kyphosids (aka nenue, chubs, rudderfish) are popular food fare among the Pacific Islands, and there are species native to much of the world. Research has shown Kyphosus vaigiensis (brassy chub) to be amenable to larval rearing, resist skin flukes, yield commercially attractive growth rates, and produce fillets with up to 28% lipid (by dry weight).
Initial spawns from Kampachi Farms K. vaigiensis broodstock in 2017 provided preliminary data for successful larval rearing. We have built upon this groundwork through 2019 having achieved consistent high-quality spawns by reorganizing cohorts, completing a successful larval run, developing algae-based pellet formulations, and collaborating with community fishponds to incorporate this species into their production.
Our 2019 grow-out studies of juvenile rudderfish confirm an attractive growth rate and FCR for production. The concluding blind taste test showed that quality fillets can be obtained from low-oil, fish-free diets with little discernible difference in flavor and texture. The successful culture of high-quality herbivorous marine finfish could provide a sustainable, low-cost option for fish farmers and seafood consumers.