SEA 



SCIENCE 



Dawn, a charter boat owned by Peter 

 Manual. 



Crucial Data Gathered 



Michael Orbach, Duke Marine Lab 

 director, also knows the thrill of the 

 catch firsthand. While assisting the 

 research team, he pulled in two giants, 

 including one at 410 pounds. But 

 Orbach says the excitement from 

 gathering research data on these 

 large fish of breeding age is even 

 greater. 



The tagging effort is a cooperative 

 venture for the scientific and fishing 

 communities. 



"This was an opportunity for the 

 fishers to gain a better knowledge of 

 these fish and for the scientists to learn 

 more about our waters," Hitchcock says. 



When a fisher catches one of the 

 giants, the captain radios a surgical boat, 

 which carries the researchers. The 

 surgical boats include the Calcutta, 

 owned by Jim Bailey and operated by 

 Capt. John Jenkins; the Bullfrog, owned 

 by Capt. Bob Eakes; the Leslie Ann, 

 owned by Richard Whorly and 

 captained by Gary Stuve: and the 

 Raptor, owned by Jim Huddlestun and 

 captained by Peter B. Wright. 



Once the fish is transferred to the 

 surgical boat, researchers implant an 

 archival tag that will determine move- 

 ment. The tag has an external sensor that 

 can measure depth, light and external 

 temperatures. When a tag is retrieved, 

 researchers download the data to 

 calculate the daily location of the fish 

 and its diving activity. 



Though expensive, an archival tag 

 may provide data over several years, 

 thus offering detailed migration patterns 

 of western Atlantic bluefin tuna. North 

 Carolina fishers assist the research 

 efforts by paying for some of the 

 archival tags, which cost $1,500 each. 

 Most tags are paid for with National 

 Marine Fisheries funds and private 

 grants. 



The researchers also track tuna by 



Fishers are strapped in for safety. 



using pop-off tags, which are designed 

 to stay on the fish for a preprogrammed 

 time. The tag has a built-in corrosion 

 point, which allows the tag to break off 

 and float to the surface, transmitting its 

 accumulated data to a satellite. 



In 1996 and 1997, Block's team 

 recovered data from 35 of 37 satellite 

 tags. The scientists were able to track 

 tuna that moved up to 1 ,670 nautical 

 miles in 90 days. Some of these fish 

 crossed the line that separates eastern 

 and western management zones for the 

 international bluefin fishery. 



Socioeconomic Benefits Noted 



The biological data from tagging 

 programs are valuable. But catch-and- 

 release programs offer great economic 

 benefits to coastal communities even 

 after the biologists have completed their 

 projects. 



Communities that encourage 

 anglers to release their catch will not see 

 their bluefin season hampered by 

 landing quotas, says Robert Ditton of 

 Texas A&M University, who studied 

 the economic impact of the bluefin 

 fishery in Hatteras. 



In fact, Ditton' s research suggests 

 that charter captains charge more for 

 anglers who want to take home the catch 



because they are detracting from the 

 long-term survival of the fish — and the 

 sustainability of a bluefin season. 



Scientific tagging is only one aspect 

 of releasing fish. "Anglers will practice 

 catch-and-release because they are 

 intrinsically motivated," Ditton says. 

 "Catch-and-release is a conservation 

 statement." 



North Carolina communities could 

 consider this a marketing strategy. 

 "Those who depend on the economic 

 benefits of the Hatteras fishery need to 

 make a greater effort to attract a new 

 market segment of bluefin tuna anglers, 

 namely those with more experience in 

 bluefin tuna fishing and an appreciation 

 for the catch-and-release experience 

 afforded uniquely in the Hatteras area," 

 Ditton recommends. 



In 1997, bluefin anglers spent more 

 than $3.6 million in Hatteras, Ditton' s 

 study shows. A detailed census of those 

 anglers showed 1 ,020 charter-boat and 

 370 private-boat tuna trips from mid- 

 January through late March. And, Ditton 

 points out, the 1997 season occurred with 

 a minimum of regional, statewide or 

 national publicity. 



But the word about North Carolina 

 bluefin is getting out to a wider fishing 

 audience each year. "People are flying in 

 from all over the world," Bahen says. □ 



For information on the Cape 

 Lookout Tag-a-Giant program in winter 

 1999-2000, contact Bill Hitchcock of the 

 Cape Lookout Sportfishing Association at 

 800/251-1442 or check the group's Web 

 site at http://www.clsfa.com. For 

 information on the North Carolina 

 bluefin fishery, contact Jim Bahen, North 

 Carolina Sea Grant fisheries agent, at 

 910/256-2083. 



On the Web, learn more about 

 Barbara Block's bluefin research at http: 

 //www. tunaresearch.org. To learn more 

 about Robert Ditton 's socioeconomic 

 study of the Hatteras bluefin fishery, 

 check http.VAutra. tamu. edu/rbaVtuna. htm. 



26 SPRING 1999 



