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September 23, 2008     Cape Gazette
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September 23, 2008

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T 4 TUESDAY, SEPTEMBER 23 - THURSDAY, SEPTEMBER 25, 2008 NEWS Cape Gazette Students sink teeth into sandtiger shark research Delaware Bay research aims at saving species By Leah Hoenen he sun is starting to climb as the Tank heads out into the Delaware Bay. It's the second trip of the day;, hours earlier, the boat's crew - a fisheries scientist and three of his students - laid thousands of feet of fishing lines across the Delaware Bay. Now, they are returning to the lines to see what they have caught. What they are hoping to fred is sandtiger sharks. Fierce-looking sandtigers, with their rows and rows of razor-sharp, jagged teeth, are the largest predators that make a regular appearance in the Delaware Bay. Captured sandtigers are popular for aquariums because, while they look fero- cious, they are actually quite docile. Beyond their shy, peaceful personali- ties, scientists know little about the sharks. "My research is important to get base- line information on the species," said Delaware State University graduate stu- dent Johnny Moore. This is Moore's third summer on the bay tracking sandy-brown tiger sharks. But he's not complaining. He is working on groundbreaking research on a species that could be disappearing. The day is wanning up, but the breeze from the water is cooL Moore explains that there are no population estimates for sandtiger sharks, a problem he hopes his research will help remedy. Moore's'advisor, fisheries professor Dewayne Fox, pilots the boat up the bay, heading for the teams' flagged buoys. The sharks are considered a species of special concern. At one time, fLshermen caught many sandtigers, but after 1998, the numbers of accidentally caught sandtiger sharks fell off sharply, Fox said. The National Marine Fisheries Service this year plans a status review that could lead to placement on the endangered species list, Fox said. Researchers will spend the day catch- in_g, tagging and trackin_g sandtigers in the bay, to figure out what makes the bay so appealing to them. "One of the fLrSt things you need to know when you'r doing an assessment is where they go and when they're there," said Fox, chairman of the Department of Natural Resources and Environmental LEAH HOENEN PHOTO CRADLING A NEWLY TAGGED Sl-lARKare (I-r) Naeem Willett, Jennifer Hampton and Johnny Moore, Control Finfisheries Advisory Council. Moore is working with gradu,.a, te stu- dent Naeem Willett, who is wrapping up graduate research on sandbar sharks, and undergraduate Jennifer Hampton, a re- cent transfer from the University of Hawaii. F.da is a nmsery Scientists know that young sandtiger sharks head to the Delaware Bay after they are born, or pupped. The estuary is a nursery ground where sharks fend protec- tion from predators and plenty of food. As summer wanes, the sharks leave the bay and head south. Moore says there isn't much the sharks won't eat - they prey on almost any smaller fish. They have baited ...... the . 1,000- foot lines with chunks of mackerel. Fox pilots the boat up to a flag and a stu- dent grabs it. They take turns pulling in the line, hand over hand, pulling fksh offbaited lines. The line is pulled in quickly;, each two-meter-long section of thick fishing line dan- gling from it is pulled off and put in a plastic can - hooks around the rim. Live fish are quickly un- hooked - some dripping blood from fresh shark bites - and re- leased. The remains of unfortunate dogfish that became lunch to a sandtiger are tossed aside. The researchers use special hooks with barbs that are depressed, to avoid tearing the skin of the sharks, minimizin_g stress. Several sandbar sharks went for the mackerel too, " and, like the dogfish, they are "  released. The sandtigers are often found around submerged structures in the bay, such as shipwrecks or artificial reefs, and at points where water depth changes, such as at the edge of a sandbar, Moore said. T00g=gt00t00r At each place the baited lines are pulled in, Moore notes water tempera- ture, salim'ty and dissolved-oxygen levels, information that might help him draw a correlation be- tween water condi- tions and shark be- havior. Willett says know- ing what the water is like at each location helps researchers dis- cover where sharks are likely to be found. Fox said scientists have found male sandtiger sharks are more commonly found in shallower, less saline water than females, which tend to congregate in deeper, saltier water. A sandtiger comes into view, shimmer- ing below the surface of blue-green water, as the line pulls it closer to the side of the boat. Instantly, the team moves into high gear. They prepare to do surgery on the sharks - on-deck for the smaller sharks, over the side of the boat for larger ones. This one is large. Moore pulls out his sur- gery kit - scalpel scissors and suture material, which is doused in the disinfec- tant Novalsan. He dic- tates numbers to Fox from the tracking de- vice he will implant in the shark. It is black and slightly sticky;, its faint ticking sound will be picked up by" hydrophones within and without the bay. This team is working with re- searchers from the University of Rhode Island and federal : agencies. sandti sharks i. aquaria are often ones caught in the De'ware Bay Hydrophones in other waters will iden- tify these sharks by re- ceiving information sent by the implanted tags. W'fllett and Hamp- ton anchor them- selves on board with their legs against the side of the boat. They lean far over and cradle the shark against the side of the boat as Fox turns a rope in- to a sling. Sharks, once turned upside down, will enter a sleep-like state, almost as if anesthesia had been administered. As soon as the shark is rolled over, it stops moving, as if in a deep sleep. Moore makes a quick incision on the shark's pale underside, but the skin is thick and tough and resists the cut. Leaning over the side, Moore pushes the tag under the skin and begins to suture. Fox said all the materials he and his stu- dents use minimize the impact of their research on the sharks. The tags are ex- pensive, and the team will not learn any- thing if tagging the sharks harms or kills them. As Moore finishes his sutures, Fox cuts two wedge-shaped tags out of the shark's SUBMITTED PHOTO DELAWARE STATE UNFIr'ERSITY fisheries professor Dewayne Fox leans over the side of a work boat, preparing to operate on a shark. tail f'm. He says those wili be analyzed for DNA. Before the shark can go, Moore has to insert another tag next to its dorsal fro. This tag will win a reward for fisher- men, a hat, if they catch the shark and mail in the tag. The shark's length is not- ed, and it is let go. It suddenly overcomes its drowsiness and swims away. The next shark is small enough it can be brought on board to be tagged. Fox es- timates its age at 3 years. Upside down on wet towels, the shark is still while Fox cuts a short incision and inserts a tag. Hampton pours bay water over the shark's head and gills and the team works fast to avoid causing undue stress. Tracking bay's data Fishing isn't all the students have planned for the day. They have to down- load tracking data stored in each hy- drophone before they head in for the evening. There are 72 hydrophones throughout the lower bay. Signals from the sharks' acoustic tags are picked up by the hy- drophones, helping researchers keep track of the sharks' movements. Downloaded onto a laptop computer, the transmissions tell researchers which fish - shark or sturgeon or other tagged species - passed by, at the exact time on which day. Data from the hydrophones allows scientists to develop models to predict where these sharks will be and when, leading to a better understanding of sandtiger behavior. Moore said he hopes his research will give scientists enough insight into shark habits that they can develop protection measures for them, such as limiting ac- cess to nursery areas. The sun is now low as they head home. After a long day on the water, the re- searchers know they still have work to do. When the sharks have headed south for the year their focus will shift off the water and to developing the models fed- eral officials can use to try to save the species.