WWW.WAS.ORG • WORLD AQUACULTURE • DECEMBER 2012 13 colleagues at the laboratory in Cook produced a stream of publications that established the nutritional requirements and deficiency signs of fish for vitamins and amino acids. The methods and techniques developed at the Western Fish Nutrition Laboratory were subsequently used by others around the world to estimate the nutritional requirements of many species of fish. The facility in Washington was built to conduct research on Pacific salmon fry and fingerlings to support the growing salmon hatchery program in the Pacific Northwest. Pacific salmon spawn in the fall and their eggs hatch in late winter. Therefore, nutritional research using salmon fry and fingerings was seasonal. Further, the laboratory was supplied by relatively cold water that varied in temperature over the growing season. In the late 1950s, Halver set out to find a second research site with a water supply that could support research year-round. He settled on a U.S. Fish and Wildlife Hatchery in Hagerman, Idaho, that had an abundant supply of constant temperature water, and built a new laboratory that used rainbow trout as the test fish for nutritional research. Today, this laboratory is the University of Idaho’s Hagerman Fish Culture Experiment Station. Although he was involved in a wide range of nutritional and pathological research, Halver’s particular research interest was in the water-soluble vitamins and their de ciency syndromes, with chinook salmon as a model species. Using his test diet, he deleted one vitamin at a time from the diet, added it back in increments, and measured the growth and pathological responses of the fish. He did this for thiamin, ribo avin, pyridoxine, pantothenic acid, biotin, niacin, folic acid, choline, ascorbic acid and vitamin B12. He also de ned the de ciency signs for vitamins A, D, E and K. However, probably his most important work was leading the team that carried out basic research on the toxicity of aflatoxins, derived from Aspergillus fungi, to fish. Aspergillus grows on moldy grains and oilseeds, especially corn and peanuts, and aflatoxins are dangerous to both man and animals. This work was undertaken at the Hagerman Laboratory after a widespread outbreak of hepatocarcinoma in hatchery rainbow trout across the US. There were many theories put forth to explain the cause of the outbreak, but Halver showed that aflatoxins in the diet were the primary cause and that trout were orders of magnitude more sensitive to aflatoxins than rats or other animals. It was for this outstanding work, of importance to all vertebrates, that he was elected in 1978 to the U.S. National Academy of Sciences, the first sh researcher to be so honored. He also chaired committee that produced the first National Research Council’s bulletin on the nutrient requirements of fish, adding fish to the list of other domestic animals and livestock in the NRC “Nutrient Requirements of Domestic Animals” series. In 1978, Halver retired from the U.S. Fish and Wildlife Service and became a professor in the College of Fisheries at the University of Washington, where he continued his work on vitamins, showing that new, protected forms of vitamin C cured sh scurvy and reduced mortality from bacterial and viral diseases such as IHN. He also conducted studies on the role of polyunsaturated fatty acids in cell membrane structure and mechanisms involved in preventing fatty acid oxidation, in particular the role of selenium. He continued to work at the University of Washington after his second retirement, becoming an Emeritus Professor in 1992. Although technically retired, he remained active, collaborating with scientists around the world and to travelling to various countries on speaking tours as recently as this year. His last scientific paper, published in 2012 in the Proceedings of the National Academy of Sciences, was entitled “Sphinglomyelin and sphingomyelin synthase (SMS) in the malignant transformation of glioma cells and in 2-hydroxyoleic acid therapy.” Clearly his competence in cell biology and biochemistry covered a wide range of topics that went well beyond fish nutrition. Halver also contributed greatly to the development of aquaculture in other countries. In particular, he made a major contribution to the development of the research capacity and commercial industry in Hungary, where he was elected a member of the Hungarian National Academy of Sciences in 1998, and in Thailand, where he collaborated with staff of the National Inland Fisheries Institute for over 20 years, directing the development of their research centers. He was named one of the “Leading Scientists of the World” in 2005 by the International Biographical Centre of Cambridge, England. He was made an Honorary Life Member of WAS in 2009 and received many other honors from many countries. Halver is probably best known around the world for his book “Fish Nutrition,” published in 1972. The book was the standard text on the subject and an essential resource for anyone involved in sh feed formulation, manufacture, or fish nutrition research. A third edition appeared in 2002. Halver also left a rich legacy in terms of training graduate students and interacting with young scientists. He maintained an active correspondence with many researchers literally until the day before he died. He was a dynamic and energetic individual who unhesitatingly spoke up at scientific conferences, pointing out the deficiencies in some research presentations to the dismay of the person being addressed, but more importantly, praising good research. Young scientists receiving such praise years ago remember it vividly to this day and credit Halver for inspiring their careers. Another aspect of his legacy was the establishment of funds at the University of Washington to provide scholarships for graduates students studying fish nutrition and also at Washington State University to support the annual “Halver Lecture” on fish nutrition. Finally Halver enjoyed life. He had a long, happy marriage to his wife Jane that produced five children. In recent years he was occupied with the activities of his numerous grandchildren. Overall, John Halver set the bar for fish nutrition research, bringing solid nutritional biochemistry to the subject and building the foundation for today’s global aquaculture industry by quantifying the nutritional requirements of fish. All fish feed production around the world is based on his pioneering research. — Ronald W. Hardy, Hagerman Fish Culture Experiment Station, University of Idaho
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