SEA 



SCIENCE 



TOP ROW, LEFT TO RIGHT Nate Bacheler surgically implants a traiismitter in a juvenile red drum in the South River. • Advertisements are posted at boat 

 ramps and tackle shops to explain rewards for catching red drum. • This radiograph shows the transmitter that will track fish. • Bacheler holds an adult red 

 drum caught in the lower Neuse River. BOTTOM ROW, LEFT TO RIGHT: Technician Jason Edwards holds a tagged red drum before its release into the lower 

 Neuse River. • Edwards releases the tagged red drum into the river. • The technician uses a receiver to listen to telemetered red drum in South River. 



RED DRUM PROGRAM 



DMF biologists and volunteers began 

 tagging red drum — also known as channel 

 bass, spottail bass, puppy drum or redfish — 

 in 1983. 



In 2004, Sea Grant researchers joined 

 the program and began using new types of 

 tags and tagging designs. Scientists attach red 

 and yellow tags to red drum. Each color tag 

 brings a different reward and is used to examine 

 the reporting rate or odds that the tag will be 

 returned. A fisher gets $ 100 for a red tag, and a 

 T-shirt, hat or $5 for a yellow tag. Most of the 

 fish tagged were between 15 to 18 inches long. 



To estimate fish mortality, the scientists 

 have been surgically implanting transmitters in 

 the body cavities of 162 red drum since 2005. 

 The transmitter emits an ultrasonic signal that 

 helps scientists locate and identify the fish. 



"Each fish emits a unique sonic code," 

 says Buckel. "We can follow the fish for up to 

 two years. The study helps us to understand 

 movement rates and habitat-use patterns. If a 

 fish dies of natural causes, it transmits a signal 

 from the same location over many months." 



And researchers also can determine 

 when a fish is caught, adds Buckel. "This 

 methodology was developed by Hightower 

 and Pollock on striped bass in North Carolina 

 reservoirs and is providing good data for an 



estuarine application," he adds. 



Now, the Sea Grant/DMF team is 

 analyzing DMF red drum data collected from 

 volunteer anglers over a 20-year period. 



The scientists found that early in the 

 spring, adult red drum are captured mostly in 

 Ocracoke Inlet and off ocean beaches, Burdick 

 says. "This is followed by a period of low 

 catches in the late spring and early summer 

 when red drum spread out as they migrate 

 through the middle of Pamlico Sound." 



During the late summer and early fall, 

 catches increase on the west side of Pamlico 

 Sound, she adds. Then in September and 

 October, fishers begin to catch red drum again 

 in the inlets and on the ocean beaches. 



The tagging hasn't shown where the 

 majority of red drum spend their winters, 

 Burdick says. "However, many scientists 

 speculate that they move into offshore, deep- 

 water habitats where water temperatures are 

 stable." 



BIG CATCH 



The Tar Heel state is famous for its trophy- 

 size red drum that weigh more than 40 pounds. 

 Such large fish are usually caught in the surf and 

 sound between Oregon Inlet and Cape Lookout. 



In North Carolina, anglers have caught 

 seven of the nine largest red drum on record. 



The world record was set in 1984 when a 

 recreational angler reeled in a 59-inch, 94.2- 

 pounder off Hatteras Island. 



Although most red drum caught in the 

 state's waters are under 20 years old, a few 

 five nearly as long as some humans. "North 

 Carolina biologists determined the age of 

 one drum to be 62, the oldest found so far in 

 the state," according to Burdick. Researchers 

 determine the age of the fish by looking at 

 otoliths or ear bones and examining the number 

 of rings. 



North Carolina is not the only place where 

 the red drum is sought. 



It also is the star of the once ubiquitous 

 Louisiana-style blackened redfish. Despite its 

 popularity, there is a limited supply of the fish. 



By the time stock assessments were 

 conducted in North Carolina in the early 1990s, 

 red drum were "overfished," according to 

 DMF. The status of red drum is based on its 

 spawning stock or the number of fish surviving 

 to maturity. 



The dwindling red drum stock led DMF 

 to enact regulations in the early 1990s, reducing 

 the number and limiting the size of fish kept. 



Using data through 1998, the most recent 

 stock assessment evaluated the regulatory 

 changes of the early 1990s. While red drum 



Continued 



Coctstwatch I Autumn 2006 I www.ncseagrant.org 25 



