According to “Wasted Catch: Unsolved Problems,” a report released March 20 by Oceana, global bycatch may amount to 40 percent of the world’s harvest, including 17-22 percent of the US catch every year.
Jon Warrenchuck, a senior ocean scientist for Oceana in Juneau, Alaska said much of the data used to compile the report came from National Marine Fisheries Service bycatch reports from 2005 and updates made in 2010.
Fisheries cited as the nine dirtiest US fisheries include the Gulf of Alaska flatfish trawl fishery, the California set gillnet fishery, and the California drift gillnet fishery.
According to Oceana, the Gulf of Alaska flatfish trawl fishery, with a discard rate of 35 percent, throws more than 34 million pounds of fish overboard in one year, including 2 million pounds of halibut and 5 million pounds of cod.
The California set gillnet fishery was cited for bottom-set gillnets that entangle and kill thousands of marine mammals, sharks and turtles every year, and the California drift gillnet fishery, in which drift gillnets are used to catch swordfish and thresher sharks, was cited for a 63 percent discard rate.
NMFS data sets were used for the report. Data for the California fisheries cited is at http://www.westcoast.fisheries.noaa.gov/fisheries/wc_observer_programs/sw_observer_program_info/data_summ_report_sw_observer_fish.html
Oceana’s report called for phasing out use of drift gillnets, replacing them with cleaner gear, such as harpoons, which result in zero bycatch.
The report is critical of the use of gillnets, where the netting can be up to two miles long and anchored hundreds of feet deep or left floating at the surface. “Drift gillnets more than one mile long are so harmful to the marine environment that they have been banned on the high seas by the United Nations and by many other countries,” the report said.