More than half of the world’s marine protected areas are not doing the job they were created to do, mainly due to illegal overfishing, according to a Tel Aviv University study.
Marine Protected Areas, or MPAs, are designed to protect marine ecosystems and help conserve and restore populations of fish and marine invertebrates, whose numbers are increasingly declining due to overfishing.
When an MPA is functioning properly, the marine stocks it contains are expected not only to rebuild within the protected area, but also to overflow and migrate beyond, thus boosting numbers immediately outside the protected area. ‘AMP.
The effectiveness of AMPs has been proven in thousands of studies conducted around the world. But most only sampled “inside” and “outside” MPAs, with little research on intervening areas.
Doctoral students Sarah Ohayon and Itai Granot combined estimates of the number of fish and invertebrates belonging to 72 taxonomic groups, with their spatial distributions in 27 MPAs in different parts of the world where fishing is prohibited.
Under the supervision of Professor Yoni Belmaker of the Department of Zoology at Tel Aviv University and the Steinhardt Museum of Natural History, the two discovered that “there is a large and constant side effect that spans about 1 kilometer (0.62 mile) inside the MPA, in which [fish] population sizes… are 60 percent smaller than those in the core area, ”mainly because of fishing.
MPAs of less than ten square kilometers, or 6.2 square miles – and these account for 64% of all “no-take” MPAs in the world, where fishing is completely prohibited – “may only contain about the half (45-56%) of the fish population ”which is commonly accepted, the researchers recently wrote in Nature Ecology and Evolution.
Some 40% of MPAs cover only one square kilometer, which means the entire area is likely experiencing this edge effect, they added.
The results, the researchers concluded, indicate that “the global effectiveness of existing non-harvesting MPAs is much lower than previously thought.”
No side effects were found in MPAs that had no-fishing buffer zones created around them and there were less of these effects where there were no buffer zones but bans. of fishing were applied.
“These results are encouraging,” the researchers said, “because they mean that by establishing buffer zones, managing fishing activity around MPAs and improving enforcement, we can increase the effectiveness of the MPAs. AMP existing and most likely also increase the benefits they can provide by fish overflow.
In Israel, much hope rests in the series of marine nature reserves along Israel’s northern coast, where six investigations have been conducted under the direction of the Israel Nature and Parks Authority since 2015, the most recent in 2019.
They found that since a fishery reform in 2016 and the creation of a maritime law enforcement unit within the INPA in 2018, the number of commercial fish in the Achziv-Rosh reserve HaNikra, in northern Israel, the largest and oldest, has tripled. than those outside the reserve. The number of groupers – which are commercially important but also sensitive to fishing – was four times greater than those outside, and their biomass (living matter) was eight times greater.
The number of groupers has increased in all marine reserves, as well as outside them, suggesting – according to scientists – that the existence of reserves and the application of fishing bans during the breeding season were having an effect. positive.
Outside of the breeding season, groupers in reserves were able to grow well, produce more offspring, and resist disease and pests better, the research suggested.
Yigal Ben-Ari, head of maritime law enforcement at INPA, told The Times of Israel that he “felt” stabilization, even a slight improvement, along Israel’s part of the Mediterranean Sea.
The 2016 reform banned certain types of fishing, determined the minimum sizes of fish that could be caught (to give juveniles the chance to reach sexual maturity and reproduce), fixed the sizes of holes in the nets, empowered a director of fisheries to be banned during the breeding and recruitment seasons (a stage in the growth of juvenile fish) and entrusted INPA with the responsibility for enforcement.
This enforcement unit, now in its third year, has already opened 1,300 violation cases and fined approximately 2 million shekels ($ 615,000). Fines start at 750 NIS ($ 230). Just a week ago, the unit confiscated a fishing boat and fined the owner 8,000 NIS ($ 2,465) and an additional 20,000 NIS ($ 6,160) if regulations are broken again. .
Dr Nir Stern, who began monitoring fish populations at the country’s Institute for Oceanographic and Limnological Research in 2014, said there was no actual data from prior to fisheries reform that could be used to assess whether overfishing has occurred.
His research shows ups and downs in different fish populations, he said, adding that it was too early to link trends to the 2016 reform and the implementation unit.
“People who dive say they see more fish than usual,” he said. “I think the sea is recovering, but it takes time. “
Ben-Ari stressed that most recreational and commercial fishermen obey the law and share INPA’s interests in maintaining healthy seas.
But with 12 inspectors responsible for the 190 km (118 miles) of Mediterranean coastline, one for the 14 km (8.7 miles) of Eilat coast (and one for the Sea of Galilee, a lake), the unit is stretched .