August 5, 2005
John Leffler is the scientist concerned with Seafood Health and Safety. He was a college professor for 26 years, and his interest in aquaculture led him to Hollings. Such a nice man-I would have liked to be in his class.
At Hollings, his department tests domestic and foreign, wild-caught and farm-raised seafood for safety and nutrition. One implication for human health is that aquacultured specimens have an altered ratio of omega 3/omega 6 fatty acids due to their largely vegetarian diet in farms, which may impact heart health. John is experimenting to see if diet can be altered in the last month for farm-raised animals to restore the healthy ratios. By the way, John says foreign seafood is safe, and he also told me the pale color in domestic versus wild-caught salmon is just due to different dinoflagellates in their diet. Since I think that aquaculture is becoming more and more important in feeding the world, it's good to know we can do it in a safe and healthy manner.
Waddell Mariculture Center is a Department of Natural Resources facility (Remember partnerships!) south of Beaufort, about a 11/2 hour ride. What a cool place! Huge outdoor ponds where shrimp and red drum are raised, plus labs with shrimp hatcheries, cobia and red drum in recirculating tanks, where research is done on salinities, feeds, pollutants, etc., plus many greenhouses where individual research projects are ongoing. Besides all this, there are other large outdoor tanks available for more research! Al Stokes, the director, told me he's been trying to get teachers to put small recirculating systems in schools, without much success. Hard to believe! In my area, there are four large programs in high schools, including mine, and lots of small projects in middle (and even some elementary) schools!
Anyway, the red drum and cobia are mainly raised for release into the wild to supplement wild stocks, and the shrimp to determine economically feasible procedures for safe and healthy commercial shrimp fisheries. Shrimp are raised in recirculating systems (tanks with pumps and filters), raceways (large 50' X 125 rectangular closed ecosystems) in which warming the water can produce 3-4 crops per year, and outdoors in ponds, where the supplementation of natural food can get the feed conversion ratio down to 0.94: 1. A FCR of 0.94:1 means that it takes 0.94 pounds of food to produce one pound of shrimp! For comparison purposes, beef is 7:1, pork is 4:1, and fish is 2:1. In the raceways, shrimp are being raised to a 15 count/pound (big shrimp!) in just 60-70 days, at a salinity of only 15 parts per thousand. Normal marine salinity is about 35 ppt, so this is much easier (and cheaper), and the next batch will be raised at 10 ppt and so forth till they reach a limit.
This is super-intensive aquaculture, and commercially feasible. This was a fascinating trip, and Susan Lovelace and I agreed that it's a "must-see" for teachers!