- ft/ If 



South 



'ea Grant researchers at North 

 Carolina State University are turning up the heat 

 on Southern flounder to produce all-female 

 cultured stocks. The controlled-breeding method 

 relies on water temperature manipulation during 

 the flounder's early development — not on 

 genetic engineering. 



From a pure science standpoint, their 

 research results are important, since most 

 temperature-dependent sex determination has 

 been documented in reptiles, such as some turtles 

 and lizards, and all crocodiles and alligators. 



"From an economic standpoint, that is 

 significant," says Russell Borski, a zoology 

 professor and member of the flounder research 

 "dream team." 



The production of all-female stock pushes 

 the Southern flounder up a notch as a candidate 

 for aquaculture in North Carolina, he says. 



Studies show that female flounder grow two 

 to three times the size of male flounder within two 

 years — a reasonable grow-out period for 

 aquaculture operations. Given the high consumer 

 demand and high world-market value for 

 flounder, the ability to produce larger fish in a 

 short period of time could add up to handsome 

 investment returns. 



The production of farm-raised finfish, such 

 as hybrid striped bass, tilapia and trout, is 

 expanding in North Carolina, according to NC. 

 Department of Agriculture and Consumer 

 Services figures. But, there are no Southern 

 flounder-farming operations that rear fish from 

 egg to market-size here — or anywhere in the 

 U.S. for that matter. 



Japan leads the way in technology for 

 producing farm-reared flounder. For their 

 somewhat exclusive efforts, they are rewarded 

 with a per fish market price of between $5 and 



$10 per pound — more titan double the market 

 price for hybrid striped bass, tilapia or trout. 



Borski and his colleagues would like 

 nothing better than to see North Carolina capture a 

 substantial share of the profits from the global 

 flounder market. 



A step closer 



Clustered in the zoology department in the 

 NC State College of Agriculture and Life 

 Sciences, the team, along with Borski, includes 

 fellow faculty members Harry Daniels and John 

 Godwin. Adam Luckenbach, a doctoral student, 

 has been working closely with the team for four 

 years. 



Though they jokingly refer to their work as 

 "flounderology," they are serious about their 

 science and its real-world applications. 



"Aquaculture can be a lucrative alternative 

 to tobacco fanning," says Daniels, who eyes 

 tobacco greenhouses as potential settings for 

 growing Southern flounder in recirculating 

 systems. Not suited for outdoor pond culture, 

 Southern flounder do better in the warm, 

 protected greenhouse environment. 



The use of recirculating systems allays 

 environmental concerns about wastewater 

 discharge, Daniels adds. 



Collectively, the close-knit team represents 

 more than three decades of research experience. 

 Their names rum up in literature reviews of 

 aquatic research. Borski and Daniels, for example, 

 are cited for showing that flounder can be raised 

 in low- or no-salinity water; and Godwin, for his 

 genetic studies of reef fish. 



Daniels also is cited with Wade 0. 

 Watanabe, from the University of North Carolina 

 at Wilmington, who worked with Daniels to 

 develop successful Southern flounder hatchery 



protocols; and with Margie Gallagher, from East 

 Carolina University, who is an expert in the 

 nutritional aspect of flounder rearing. Their work 

 laid the foundation for the team's temperature- 

 induced sex determinant research. 



Another familiar name that crops up in 

 aquaculture citations is that of Ronald G. 

 Hodson, director of North Carolina Sea Grant. 

 Hodson is recognized as a pioneer in advancing 

 hybrid striped bass from the research laboratory 

 to successful aquaculture ventures. 



In describing the flounder team's all- 

 female stock breakthrough, Hodson says, 'This 

 research brings us one step closer to realizing 

 profitable, large-scale aquaculture operations for 

 Southern flounder." 



Each step takes patience, he adds. "It has 

 taken nearly a decade to develop successful 

 Southern flounder hatchery protocols for rearing 

 flounder from spawning to fingerling stage. This 

 may be the breakthrough everyone was hoping 

 for to ensure grow-out success from fingerling to 

 market size." 



Luckenbach says there are several 

 advantages to a monosex female culture. 



"Monosex female culture should reduce 

 the size difference between individuals during 

 the grow-out period, lessen mortality from 

 cannibalism decrease labor costs for size 

 grading, and give a higher return on investment 

 for feed and infrastructure," he explains. 



Solid science basis 



It takes solid science to develop and 

 implement reliable, reproducible methods, the 

 researchers point out Their research results have 

 been validated with the publication of peer- 

 reviewed articles in major professional journals, 



Continued 



RIGHT: Harry Daniels examines a Southern flounder on a light table to determine its readiness for egg extraction. 



12 WINTER 2003 



