Fishing Net Lands Conservation Prize

Growing up in Michigan, Norman Holy assumed the oceans were an inexhaustible resource. Holy now knows better--and is doing his own part to support marine conservation. This chemist recently netted an international award for his efforts to reduce the number of dolphins, porpoises, and whales unintentionally caught in fishing nets. More than 300,000 dolphins and porpoises as well as a dozen or so whales die this way each year, according to World Wildlife Fund (WWF) estimates.

What's more, Holy did his award-winning chemistry in his free time.

By day, Holy--a Ph.D. polymer chemist--works as a patent analyst for Bristol-Myers Squibb. At night and on weekends, he tinkers with the chemical properties of fishing nets, hoping to create nets that are safer for marine mammals. His hobby paid off last month when WWF honored Holy, along with his collaborators, commercial fisherman Don King and Canadian fisheries scientist Ed Trippel, for designing a chemically altered fishing net that may reduce so-called bycatch of dolphins, porpoises, and whales.

The team's award-winning nets are made of nylon that's been impregnated with barium sulfate. The barium sulfate makes the nylon net--which itself is nearly invisible in the water--more visible to marine mammals, Holy says. It also makes it easier for dolphins and porpoises to sense the net. These animals locate food and navigate by sending out sound waves and then detecting how long it takes for these waves to be reflected back by an object. "The barium sulfate makes the net more acoustically reflective" and thus more easily detectable, Holy says.

The team also devised safer polypropylene top ropes, which are the ropes used to tether the nets to the surface. Commercial top ropes are so strong that whales and other marine mammals that get entangled in them often can't break free. Simply substituting a smaller diameter rope won't work, Holy says, because the thinner the rope, the faster it cuts into a whale's skin.

Holy set about designing a weaker rope. "I took the Swiss cheese approach--if enough holes were created in the fibers, they would become weak," he says. "At first, I suggested to the rope maker that he use starch in the plastic, but after trying that, he called to tell me that his building smelled like burnt toast." Another idea was more workable: Manipulate the extrusion process so that the resulting rope breaks at a mere 1,100 lb, compared with the 2,500 lb that it would take to break a conventional rope of the same diameter. "Whales that get entangled in this weaker rope can break free," Holy says.

To test the award-winning rope, the team has put more than six miles of rope out in the ocean. After a year of use, no problems have occurred, Holy says, but continued testing is needed to prove that the new rope reduces whale deaths caused by entanglement.

For many years, chemistry wasn't Holy's hobby--it was his full-time job. He spent 17 years on the chemistry faculty at Western Kentucky University before moving to Rohm and Haas in Spring House, Pa., in the late 1980s. There he was charged with developing plastics that would eventually degrade under environmental conditions.

"EVERYONE ELSE was working on degradable six-pack rings and golf tees," Holy says. "No one was working on degradable plastics for the oceans," where "ghost" commercial fishing nets lost at sea "survive for decades and continue to catch fish and turtles." To address that need, Holy made a poly(ester amide) containing enough ester linkages such that, when the polymer chains eventually break, the resulting fragments would be small enough to fall apart rather than be entangled, making the net brittle. He figured fishing nets made of this polymer would eventually degrade if lost at sea.

"At first, the fishermen were skeptical," Holy says. "They called them 'Jell-O nets.' But soon they loved them." Rohm and Haas later lost interest in the project and licensed the polymer. But Holy was hooked. "It was clear to me that chemistry could create solutions to these sorts of problems."

Holy soon turned his newfound interest in fishing and conservation into a hobby. Through contacts he had made in the fishing industry, Holy found a myriad of interesting chemical challenges to work on, including building a fishing net that would catch fish but not harm marine mammals.

Holy is careful to note that the development of these nets was the result of his team's combined chemistry, biology, and fishing expertise. This interdisciplinary approach is "emblematic of how we're going to solve the bycatch problem," says Carter Roberts of WWF. Reducing bycatch is "good for fisherman, good for fish, and good for conservation. We are committed to getting their invention adopted by fishermen across the world."