By Mark Drawbridge *
As its name suggests, Aquaculture America is dominated by aquaculture interests and attendees from North America. This is especially true when compared to the Triennial Aquaculture Conference at the World Aquaculture Society Conference, which is being held in Australia this coming June. Regardless, marine finfish were well represented among the many sessions covering a diversity of important topics that typify this conference.
From a geographic standpoint, the southeast USA was the most prominent throughout the conference program with respect to a diversity of marine finfish aquaculture research activities. Species like cobia (Rachycentron canadum), Florida pompano (Trachinotus carolinus), spotted sea trout (Cynoscion nebulosus) and red drum (Sciaenops ocellatus) continue to receive attention as top candidate species in that area – either for food production, stock enhancement or both. Other species like mahi-mahi (Coryphaena hippurus), giant grouper (Epinephelus lanceolatus) and marine ornamentals like yellow tangs (Zebrasoma flavescens) were also reported on. In the southwest, white seabass (Atractoscion nobilis) and California yellowtail (Seriola lalandi) were the subjects of numerous research papers that also revealed the recent commercialization of those species in Mexican waters.
Another commercialized aquaculture species, the sablefish (Anoplopoma fimbria), was the main subject of discussion central to the northwest, although presenters discussed activities in Canada and as far south as Mexico, which is indicative of the natural range of this species. Facilitated by the location of the conference in Seattle, researchers from NOAA’s Northwest Fisheries Science Center were able to fill a half day session on this species and showcase the extensive research being conducted at their laboratory facilities and elsewhere. Surprisingly, research activities on marine finfish aquaculture in the Northeast went largely unreported at this particular meeting. Researchers from outside the USA reported a handful of papers on well known marine fishes like sea bass, sea bream, flounder and yellowtail. These papers are always well received, because they typically represent culture refinements to commercial success stories. Colleagues in Mexico reported on their work with two promising drum species – the gulf corvina (Cynoscion othonopterus) and totoaba (Totoaba macdonaldi).
From a topical perspective, perhaps not surprisingly for emerging species, research in marine finfish nutrition was at the forefront. Even in the larval rearing section, which was dominated by talks on marine fishes, researchers reported on their ongoing quest to refine protocols and quality of live feeds, and to optimize feeding regimes, especially in the co-feeding phase. Reducing reliance on live feeds continues to be a focus of research and in that regard research teams are seeking to develop and test open formula microdiets that can subsequently be optimized for each species. Other nutrition sessions encompassing talks on marine fishes included the use of soy in aquaculture; general nutrition; taurine; pre-biotics, probiotics, and immunostimulants; lipids; and ingredient evaluations. While there clearly remains plenty of research to do in determining basic nutritional requirements for many of the species, much research continues to be focused on enhancing the economic and environmental sustainability of diets relative to alternative ingredients to traditional sources of fish meal and oil. The importance of taurine in diets of marine fish continues to receive great attention. The topic garnered a half day session at the conference with eight of nine species-specific papers focused on marine fish. The importance reported is two-fold – first as alternative ingredients are explored for growout diets, taurine is often deficient, and secondly, traditional live feeds like rotifers are deficient when compared to natural live prey like copepods.
Using fish nutrition as an example, the scientific productivity bound in the conference program was remarkable, especially acknowledging the economic down turn and the associated competition for fewer and fewer research dollars in recent years. For those seeking expertise in this arena in the USA, the government laboratories of Barrows at USDA and Johnson at NOAA NWFSC are clear go-to centers. Trushenski’s laboratory at Southern Illinois University is very active and clearly illustrates the fact that collaborative research on marine fish does not have to be limited to coastal states. The Gulf of Mexico is loaded with expertise coming from the Davis laboratory at Auburn and Gatlin’s laboratory at Texas A&M. The Langdon laboratory at Oregon State University is focused on larval nutrition and continues to innovate in that sector.
In light of the economic climate, the tenor at the conference remained one of optimism for growth in the marine finfish farming sector. Reports of commercially acceptable survival rates permeated the discussions with an acknowledgement that additional refinements could greatly improve seed quality and overall robustness. Of course, commercial farming success stories for marine fish remain elusive in the USA as regulators and politicians continue to wrestle with a meaningful commitment to foster industry development in ocean waters. Progress using recirculating aquaculture systems for marine fish was not reported at this particular conference but clearly that remains an opportunity that bypasses the regulatory/political conundrum surrounding ocean farming. Fortunately, the collegiality and shared research findings associated with conferences like Aquaculture America ensure progress in the sector as a whole. More and more of the fruits of these labors are showing up on restaurant menus for all to enjoy!
Mark Drawbridge has a B.S. degree in biology and a Master’s degree in Marine Ecology. He’s currently a Senior Research Scientist at Hubbs-SeaWorld Research Institute in San Diego, where he also serves as the Director of the aquaculture program.