Formulated Sardines: a high-moisture, sustainable diet for fastidious feeding high-value marine fish

The current dependence of grouper and tuna aquaculture on "wet fish" diets poses challenges for the long term viability and scalability of such aquaculture in the U.S. and internationally. There is a recognized need for alternative feed formulations (those including agricultural oils and proteins, such as soybean meal, soy protein concentrate, wheat and corn gluten, canola, poultry and other animal processing by-products, microalgae, etc.), but these top-end predators are often highly averse to eating conventional hard, extruded pellets; and, in aquaculture, are often fed a diet of "trash fish" bycatch or whole fresh/frozen forage fisheries products such as sardines or pilchards. Continued reliance on these limited, price-volatile, wild-caught "wet fish" resources present a critical constraint to the sustainable expansion of high-end marine aquaculture and its ability to produce healthy, efficiently grown, desirable fish for a growing and increasingly prosperous global population. Kampachi Farms has sought to resolve this issue by adapting the USDA-developed "Formulated Sardine" - a fibrous, high-moisture, soft extruded strip of formulated feed which more closely mimics the texture of natural fish - to high-end marine fish such as groupers and tunas. By switching to a formulated diet, sustainable, scalable agricultural oils and proteins can be incorporated into the diets of these high-value fish, rendering their expanded commercial production both more economically attractive to investors, and more environmentally sound.Phase I research thoroughly demonstrated the feasibility of this concept by conducting palatability and grow-out trials to determine if Formulated Sardines would be accepted by high-value marine carnivores and generate acceptable growth rates attractive to commercial culture. Several experimental formulations of Formulated Sardines were developed and manufactured by USDA ARS fish nutritionist Dr. Frederic Barrows, including the early deployment of a 100% fishmeal-free blend, which became the focus of grow-out trials during this study. All experimental diets were formulated to be nutritionally suitable for the two species tested: the relatively sedentary Giant Grouper (Epinephelus lanceolatus) and the more active kampachi (Seriola rivoliana). Growth, feed conversion ratio (FCR) and feed waste metrics were compared between populations of both species fed wet fish diets, pelleted diets and Formulated Sardines. The results of these trials were promising, with Formulated Sardines accepted by both grouper and yellowtail at comparable rates to their standard feeds, producing no significant differences in growth performance or FCR. The fact that these results were attained with a 0% fishmeal formulation, months to years ahead of when that development was expected, only underscores the Formulated Sardine feed format's potential for commercial utility in the culture of high-value marine finfish such as grouper and tuna. The apparent palatability of these diets in Grouper and Yellowtail studies also suggests several additional areas across the hatchery production cycles of these species where Formulated Sardine-type diets could provide significant advantages over traditional feeds.Kampachi Farms therefore proposes, through this Phase II research, to bring this novel aquafeed format closer to commercial viability by expanding into trials with Pacific Bluefin and Yellowfin Tunas, assessing its efficacy in specialty formulated broodstock diets, and determining the effectiveness of a derivative soft "crumble" product in accelerating weaning of highly prey-selective, difficult-to-rear marine finfish larvae onto formulated feeds.