Japanese scientists believe that Chinese fishermen are dramatically under-reporting their catches of mackerel in the Pacific, potentially affecting broader maritime resources.
Scientists of the Yokohama-based Japan Fisheries Research and Education Agency (JREA) have compiled a study of movements of Chinese fishing vessels in calendar 2016 and concluded that they caught as much as 400,000 tonnes of mackerel.
That figure is significantly higher than the 143,000 tonnes that China reported to the North Pacific Fisheries Commission that its fisherman had brought ashore.
The commission opened its three-day annual session in the city of Sapporo on Thursday and the Japanese delegation intends to use the forum to call on member states – which also include Taiwan and South Korea – to accurately report catches.
Masatsugu Takano, a research coordinator for the JREA, said the agency carried out a study in an area of the North Pacific around 200 nautical miles off the coast of north-east Japan last year.
The agency used data gathered by US weather satellites and provided to researchers to identify light sources in the fishing grounds, which were beyond the limits of Japan’s Exclusive Economic Zone.
The agency then used the automatic identification system that is installed aboard larger vessels to identify their nation of origin, while fish stocks were determined by the temperature of the sea water.
The research identified more than 1,000 Chinese ships of more than 1,000 tonnes. Japan’s fisheries patrol vessels also identified a large number of vessels that carried no identification, the Yomiuri newspaper reported, with some of the ships changing their names between sightings.
The agency reached its estimate of up to 400,000 tonnes being landed by Chinese vessels by determining the number of times they returned to ports in mainland China to unload.
Takano told the South China Morning Post that the JREA only carried out the research and provided it to the government and the international fisheries commission. Signatory nations agreed at the founding of the commission in 2015 to report catch totals each year, along with establishing a fishing boat registry system.