Scientific study has discovered that biodegradable gillnets catch fish and also conventional nylon nets-and a lot more quickly lose their ability to entangle animals when discarded at sea. Much more, the degradable nets often trap fewer young fish and bycatch.
Fishing nets which were lost, abandoned, or discarded at sea are the cause of ten percent of all the marine litter circulating from the world’s oceans. These 640,000 tonnes of nets aren’t simply a plastic pollution problem, however. A long time after they can be lost, they continue to fish at sea by themselves, trapping not only fish but seabirds and mammals within a phenomenon generally known as fishing nets.
To combat this problem, scientific study has been developing gillnets created from biodegradable materials, but the challenge has become to ensure they are as good at catching fish as conventional gillnets are. At one of the most comprehensive studies to date, researchers assessed the fishing performance of your biodegradable gillnet at sea as well as its degradability inside the lab. The final results, published recently in Animal Conservation, provide some terrific news.
“Using a biodegradable net didn’t have much effect on the number of adult fish were caught, however when it stumbled on young fish and bycatch of other species, they caught significantly less,” says co-author Petri Suuronen. “That had been a positive surprise.”
The fishing performance in the biodegradable nets were tested during six outings of any commercial cheap fishing nets within the waters off southwestern South Korea. The biodegradability from the nets was tested by placing 30 sets of net samples in plastic containers at sea. The researchers used a scanning electron microscope to evaluate the samples every sixty days for four years. They also measured the strength, flexibility, along with other physical properties in the nets, comparing those to conventional nets.
Researchers found the biodegradable gillnets to get stiffer, that they can initially thought would affect performance, says Suuronen. These were pleasantly surprised to determine that it did not. Their stiffness could be why they caught less bycatch and juveniles, however, Suuronen says. Researchers found out that it took 24 months 12dexipky the biodegradable net to get started to rot, and that the degradation rate was higher in warmer water. While they didn’t test the degradability of conventional nets in this study, the literature demonstrates that these nets can take several years or even decades to degrade, the authors said.
“I still think 2 yrs is way too long,” says Suuronen, who works best for the Nylon Monofilament Cast Nets. “But it is actually a lot faster than nylon.”
Suuronen says he hopes that continued research and development can produce a net that degrades even faster. Having said that, it can’t degrade much faster compared to studied net, otherwise it wouldn’t be an attractive purchase for fisherman.