 |
 |
|
The Miami Herald
Shark Science
Researching sharks from a laboratory is one thing. Chasing them, especially a tough-to-find breed, is another matter, as UM scientist Samuel 'Doc' Gruber and his crew learned in a chaotic -- but never boring -- two days on the water.
By Susan Cocking / Heral Staff
February 24, 2005
Profound scientific discoveries about fish do not pop up every day. Many take years to accomplish -- not because of the intellectual failings of the scientists, but often because of the vagaries of field research.
A prime example is University of Miami scientist Samuel ''Doc'' Gruber's research on a mysterious aggregation of large lemon sharks first spotted four years ago off Jupiter. You would think Gruber -- a brilliant scientist who has been chasing lemons for more than 40 years -- would have been able to determine what those sharks are doing by now. But he is not much closer today than when he first saw them in 2001.That is because work outside the laboratory introduces all sorts of elements that are beyond a scientist's control. In two days with Gruber and his research team off Jupiter earlier this month, I learned that doing science can be a cross between Jaws and the Keystone Kops. In other words, it is often frightening and hilarious, but never boring -- especially when things don't go according to plan.
LOOKING FOR LEMONS
Researching sharks from a laboratory is one thing. Chasing them, especially a tough-to-find breed, is another matter, as UM scientist Samuel 'Doc' Gruber and his crew learned in a chaotic -- but never boring -- two days on the water.
The object of Gruber's recent expedition to Jupiter was to catch a mature lemon shark and implant it with a sonic tag. Once the tag was implanted, Gruber could follow it around with a hydrophone and learn whether it was free-ranging or hanging with the other large lemons that school around Captain Kurle's Reef and several nearby wrecks during the winter months.
But first he and his team would have to actually catch the shark.
Watching scientists try to be fishermen is a lot like watching the Geico salesman in the TV commercial try to do the ''Robot.'' Predation by rod and reel is not something that comes naturally to some biologists. Their object in life is to try to learn more about -- and thereby protect -- marine species. So forgive them if their fishing techniques are a bit fumbling.
Deciding they needed fresh, butterflied barracudas for bait, Gruber and his team trolled tube lures and large silver spoons behind their 23-foot Tiara over a wreck off Palm Beach. When that failed to produce, four of Gruber's research assistants jumped into the water with spear guns -- two of which were in marginal working order. Still, Craig Lines and Grant Johnson managed to spear three hefty 'cudas between them.
In his haste to get one of the struggling 'cudas into the boat, Lines heaved it over the gunwales so that it glanced off the crotch of captain Tony Little, who narrowly escaped serious injury.
''His mouth was open,'' Little said. ``I knocked him down on the deck.''
Gruber clubbed the 'cuda with an aluminum bat before it could attempt to maim anyone else and dumped it in the transom.
''And this is what it takes to put a $500 transmitter on a shark that we may never see again,'' he sighed.
MOVING ON
With a sigh of relief, Little steered the boat toward a wreck about an hour away where a cluster of lemon sharks had been spotted by divers the day before. Three miles from its destination, the Tiara's twin outboards began to sputter and die. Little and Lines quickly deduced that the fuel was contaminated with water. They did what they could to clean the fuel filters, managed to restart the engines and kept going.
The boat finally arrived at the wreck around noon and anchored into a stiff, northwesterly current. A bag of menhaden chum was deployed, along with a batch of butterflied 'cudas hanging off a line on the stern. The scientists broke out four Penn Internationals loaded with 50- to 120-pound test and heavy wire leaders with 8/0 circle hooks. Two hunks of 'cuda were suspended just below the surface with balloons; two others were sent down 60 feet to the bottom.
Almost immediately, the butterflied baits tied to the boat attracted a 10-foot hammerhead. It circled the baits, but never came close enough to bite them. ''Wrong species,'' Gruber sighed. ``I really don't want to catch him.''
In the meantime, a 20-pound jack crevalle roared up and scarfed one of the balloon baits. Lines reeled it in and its carcass was added to the hanging baits.
Then, from out of nowhere, a 15-foot hammerhead charged in and chomped down on the cluster of baits. Its dorsal fin appeared nearly as large as the conning tower of a submarine. Everyone started yelling at once. Inexplicably, Gruber grabbed the shark's dorsal. There was an uncomfortable instant when it appeared the huge animal might sink the boat. It shook its massive jaws, let go of the baits, and soaked Gruber before swimming away.
''We're not successful, but we're having fun,'' Gruber said -- to nervous laughter from the crew.
HIT-AND-MISS
Several hits-and-misses occurred involving the bottom baits. No one could see what hit them, but Gruber theorized they were the large lemon sharks he was looking for.
The waiting continued. Suddenly, one of the heavy bottom rods bent over. At the same time, the drag began to squeal. Lines grabbed the rod, and someone put a stiff gimbel belt around him to aid in the fight.
After a 20-minute tug-of-war, success at last. Despite a broken snap swivel and a straightened hook, Lines reeled an eight-foot female lemon shark to the surface.
Chaos erupted on the Tiara, with lots of shouting, scrambling and cursing. Johnson managed to loop a rope around the flailing shark's tail.
It immediately tried to bite him. ''Be careful! Be gentle with her!'' Gruber cautioned.
Mark Corcoran got a section of line around the shark's pectoral fin to hold it still in the water. There was no thought of bringing it on board the boat.
Quickly, the transmitter tag was attached beneath the dorsal fin, and a tiny snip of the pelvic fin was taken for a DNA sample. Todd Gedamke recorded the shark's measurements and tag numbers. The loops around the shark's tail and fin were released, and it swam smartly off.
Gruber and Corcoran broke out a hydrophone made of PVC pipe wired to a receiver unit and stuck it in the water to listen for beeps. Through earphones, Gruber picked up the steady signal -- like a heart monitor -- coming from the shark.
He was elated. 'That's it. I'm satisfied,'' he said. ``I can't believe we got one. Now, I know this study can go forward.' Gruber and the rest of the crew packed up their gear and putt-putted back to port on one engine, arriving after dark.
They resolved to pump the bad gas out of the Tiara and try to catch another shark the next day.
|
|
|
|
|
|
|
