Researchers have discovered that biodegradable gillnets catch fish in addition to conventional nylon nets-and much more quickly lose their ability to entangle animals when discarded at sea. A lot more, the degradable nets tend to trap fewer young fish and bycatch.
Fishing nets which were lost, abandoned, or discarded at sea are the cause of ten percent of all of the marine litter circulating within the world’s oceans. These 640,000 tonnes of nets aren’t only a plastic pollution problem, however. A long time after they are lost, they continue to fish at sea on their own, trapping not simply fish but seabirds and mammals inside a phenomenon known as fishing nets.
To combat this problem, scientific study has been developing gillnets made from biodegradable materials, but the challenge has become so they are nearly as good at catching fish as conventional gillnets are. Within the most comprehensive studies up to now, researchers assessed the fishing performance of your biodegradable gillnet at sea as well as its degradability from the lab. The results, published recently in Animal Conservation, provide some terrific news.
“Using a biodegradable net didn’t have much effect on the amount of adult fish were caught, but when it stumbled on young fish and bycatch of other species, they caught far less,” says co-author Petri Suuronen. “That was a positive surprise.”
The fishing performance in the biodegradable nets were tested during six outings of the commercial cheap fishing nets within the waters off southwestern South Korea. The biodegradability of the nets was tested by placing 30 sets of net samples in plastic containers at sea. The researchers used a scanning electron microscope to assess the samples every 2 months for four years. In addition they measured the strength, flexibility, along with other physical properties in the nets, comparing these to conventional nets.
Researchers found the biodegradable gillnets being stiffer, that they can initially thought would affect performance, says Suuronen. These folks were pleasantly impressed to find out it failed to. Their stiffness may be why they caught less bycatch and juveniles, however, Suuronen says. Researchers found that it took 24 months 12dexipky the biodegradable net to get started to rot, which the degradation rate was higher in warmer water. While they didn’t test the degradability of conventional nets within this study, the literature shows that these nets can take several years and even decades to degrade, the authors said.
“I still think two years is way too long,” says Suuronen, who works for the cheap cast nets. “But it really is a lot faster than nylon.”
Suuronen says he hopes that continued research and development can make a net that degrades even faster. Nevertheless, it can’t degrade much faster than the studied net, otherwise it wouldn’t be an appealing purchase for fisherman.