Climate Change Reduces World Fish Production

KOMPAS/VINA OKTAVIA

A fisherman sorts fish at a fish port in Gudang Lelang, Bandar Lampung city, Lampung, Wednesday (23/01/2019). High waves and strong winds prevent fishermen from going to sea.

JAKARTA, KOMPAS – Cimate change has reduced marine fish stock, which has led to a decline in fish production by 35 percent. This phenomenon has posed a serious threat because marine fish is the world\'s main protein source and provides employment for 56 million people.

The latest global study was published by a team of scientists led by Christopher Free of the University of California, Santa Barbara in the March 1 edition of the Science journal. The study analyzed the history of the production of 124 fish species in 38 regions representing about one-third of reported global catches.

The researchers compared fish stock data (maximum sustainable yield / MSY) with the change in ocean temperature in the 1930-2010 period. As a result, 8 percent of the fish population had been significantly affected by global warming, while 4 percent had a positive impact.

However, the losses were larger than the benefits. According to the study, geographical location has the greatest influence on fish in response to rising temperatures. From this geographical aspect, there was a decrease in fish availability from 1930 to 2010 in the Japan Sea, North Sea, Iberian Coast, Kuroshio Current and the Celtic-Biscay Shelf region.

However, on the other hand, there was an increase in the availability of large fish in the Labrador-Newfoundland region, the Baltic Sea, the Indian Ocean and the northeastern United States.

The Indonesian condition

This study did not specifically mention the condition in Indonesia. However, as a country in which its territory mostly consists of ocean, Indonesia is considered to be very vulnerable to the change. However, data related to this in Indonesia is very limited due to a lack of historical data on national fish stock.

"The impact of the climate change requires data over a long period of time. We don’t have historical data for MSY and changes in temperature. The existing data, in fact, showed an increase in fish stock due to the government’s efforts to fight illegal fishing," climate change researcher from the Maritime Fisheries Research and Human Resources Agency, the Maritime Affairs and Fisheries Ministry (KKP), Novi Susetyo Hadi, said in Jakarta on Monday, responding to the study conducted by Christopher Free and his colleagues ..

Based on the ministry’s data, the amount of fish stock or MSY Indonesia increased steadily from 6.19 million tons per year in 1997 to 12.54 million tons per year in 2016. "The stock data shows an increase because some types of fish that were not counted in the past have now been included in the data. So, there is no connection with illegal fishing," said Alan Koropitan, the marine expert at the Bogor Agriculture Institute who is also the chairman of the Indonesian Academic Scientist Young Scientist.

According to Alan, the MSY data issued by the government cannot be used as a basis for research on the impact of the climate change on fisheries. "However, research data calculated on its own survey based on modeling can see its impact in Indonesia," he said.

Alan\'s research used a fish stock model from data on chlorophyll distribution obtained from satellites over the past 10 years. Changes in sea temperature are known to have caused marine chlorophyll, which is one of the important keys in the decline of the food chain.

"This data is then analyzed to determine the decline in MSY of small pelagic fish in Indonesia," Alan said.

Based on Alan’s study, the decrease in small pelagic fish stocks in Indonesia ranges from 90,000-100,000 tons per year. "In the food chain, everything is related to marine chlorophyll as a basic producer, but the method in calculating the stocks can be different for different fish groups. So far what I have managed to calculate is specifically for small pelagic fish," he said.

According to the Food and Agriculture Organization (FAO) report in 2018, if efforts to reduce the pace of climate warming succeed, marine fisheries production in the Exclusive Economic Zone (EEZ) will drop by between 2.8 and 5.3 percent by 2050. However, if these efforts fail and the rate of warming increases as at present, the decline in fish production in EEZ can range from 7 percent to 12.1 percent in 2050.

The study made by Christopher Free from the University of California Santa Barbara is evidence of a decline in global fish stocks that will reduce fish production. (AIK)