HERBIVOROUS MARINE FINFISH CULTURE - THE COMPELLING CASE FOR KYPHOSIDS

Marine finfish aquaculture is dominated by carnivorous species. Carnivores require diets high in proteins and oils, often fulfilled through the use of wild-sourced fish products, raising into question the scalability of the industry. Reliance on wild fish resources for fishmeal and fish oil is also a leading sustainability concern, which constrains the expansion of responsible mariculture. Extensive research (including nearly a decade of work by Kampachi Farms) is striving to identify alternative ingredients and reformulate feeds for 'carnivorous' fish - pursuing primarily plant-derived proteins and oils, such as soy. However, an alternative to carnivorous culture has been left largely unexplored - herbivorous marine finfish that do not demand fishmeal and fish oil in their diets.

Kyphosids (chubs or rudderfish; of which there are species native to all areas of the U.S.'s prime mariculture development regions) are esteemed food-fish among the Pacific Islands. Preliminary research with Kyphosus vaigiensis (Brassy chub) has shown them to be amenable to larval rearing in the hatchery, resistant to skin flukes, yield commercially attractive growth rates and produce a highly-appealing product, at up to 29% lipid (by dry weight). Our current work aims to close the life cycle of this species in captivity by refining broodstock husbandry protocols (feeding and housing regimes) and obtaining tank spawns. We are also simultaneously researching the growth rates of K. vaigiensis fed with three invasive algae species (a widespread and persistent problem in the Hawaiian Islands), as well as on low-cost commercial herbivore feeds.  The goal of this research is to establish the feasibility of their commercial production. The successful culture of these high-quality herbivorous marine finfish could provide a new, sustainable, marketable, healthy and low-cost option for fish farmers and seafood consumers.