New fishing hook reduces shark catch

June 8, 2011 By Eric Stroud
Shark Defense researcher Patrick Rice with a bonnethead shark at the Aquaranch facility in Long Key, Fla. Bonnethead sharks were used to perform the initial tests on the shark repellent hook. Credit: Florida Keys Community College

(PhysOrg.com) -- Scientists have developed a new type of fishing hook to reduce the number of sharks accidently caught from commercial fishing. The special hook, called SMART Hook (Selective Magnetic and Repellent-Treated Hook), combines two shark repellent technologies--magnetism and shark repellent metals--into standard fishing hooks.

The final product is a fishing hook that interferes with the highly sensitive electrical sense found in a shark's nose. Market-valuable fish, such as , do not have this electrical sense and are not repelled by the hook.

In 2010, with the support of a National Science Foundation (NSF) Small Business Innovation Research (SBIR) grant, Shark Defense researcher Patrick Rice and student researchers at the Florida Keys Community College conducted feeding trials with bonnethead sharks to test SMART Hooks. The sharks were simultaneously given bait attached to regular hooks and bait attached to SMART Hooks. The barbs on the hooks were removed so that the sharks were not injured. The researchers recorded the number of baits that the sharks took off each type of hook.

A standard circle hook (left) compared to a shark repellent hook (right). The shark repellent hook is magnetic and is covered with a special metal that produces a voltage in seawater. Credit: Eric Stroud, Shark Defense

Following a total of 50 tests with two different groups of sharks, researchers found a 66 percent reduction of baits eaten from small, recreational-sized hooks and a 94 percent reduction of baits eaten from larger, commercial-sized hooks. The larger hooks were able to incorporate more magnetism and shark repellent metals.

Overall, the and shark-repellent technologies used in the SMART Hook have previously shown an 18 percent to 68 percent reduction in shark catch, depending on the location and the species.

"Combining a repellent with a galvanic repellent is very important, because many studies have shown that sharks behave differently to magnets or metals alone," said Craig O'Connell, who researches the effects of magnetism in sharks with Shark Defense and publishes on the subject. "There are many species of shark, and they seek out their prey differently. Having two repellents available increases the chances that the will be deterred."

Explore further: Study: Oceans 70 percent shark-free

Related Stories

Study: Oceans 70 percent shark-free

February 22, 2006

An international team of scientists says the absence of sharks from abyssal regions of the world's oceans may mean some species are in danger of extinction.

Ongoing collapse of coral reef shark populations

December 4, 2006

Investigators have revealed that coral reef shark populations are in the midst of rapid decline, and that "no-take zones" -- reefs where fishing is prohibited -- do protect sharks, but only when compliance with no-take regulations ...

As sharks dwindle, new laws enacted

May 28, 2007

Shark fisheries in Mexico and throughout the world are dealing with proposed rules to curb shark hunting in the interest of preserving these predators.

Ocean's fiercest predators now vulnerable to extinction

February 17, 2008

The numbers of many large shark species have declined by more than half due to increased demand for shark fins and meat, recreational shark fisheries, as well as tuna and swordfish fisheries, where millions of sharks are ...

Scientists conduct shark survey off US East Coast

August 13, 2009

Sandbar, dusky and tiger sharks are among dozens of shark species living in the coastal waters off the U.S. East Coast. Little is known about many of the species, but a survey begun nearly 25 years ago is helping scientists ...

Recommended for you

Genomes uncover life's early history

August 24, 2015

A University of Manchester scientist is part of a team which has carried out one of the biggest ever analyses of genomes on life of all forms.

Rare nautilus sighted for the first time in three decades

August 25, 2015

In early August, biologist Peter Ward returned from the South Pacific with news that he encountered an old friend, one he hadn't seen in over three decades. The University of Washington professor had seen what he considers ...

Why a mutant rice called Big Grain1 yields such big grains

August 24, 2015

(Phys.org)—Rice is one of the most important staple crops grown by humans—very possibly the most important in history. With 4.3 billion inhabitants, Asia is home to 60 percent of the world's population, so it's unsurprising ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.