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Scientists face uphill battle in reviving wild yellow croaker stocks

Inkstone

發布於 2020年01月16日13:01

Scientists are stepping up efforts to protect the stocks of wild yellow croaker fish " the most popular sea fish on Chinese dinner tables " by preparing fry for release into the wild, state news agency Xinhua reported on Monday.

News of the conservation plan came about two weeks after the Chinese paddlefish, a species indigenous to the Yangtze River and one of the world's largest freshwater fish, was declared extinct, prompting a public backlash against dam-building, overfishing, heavy water traffic, pollution and other human activities on Asia's longest river.

A 10-year commercial fishing ban has been announced to protect the aquatic life in the Yangtze.

The yellow croaker is often found on tables in China, and most of those sold at market are farmed. Wild stocks have dropped dramatically over the past four decades because of overfishing, according to experts.

Scientists aiming to replenish the wild yellow croaker population have a three-year goal.
Scientists aiming to replenish the wild yellow croaker population have a three-year goal.

Last year, the coastal province of Zhejiang launched a project to try to ensure there were 1,000 metric tons of wild croaker in the East China Sea within three years, the report said.

"Wild yellow croaker fish are top among China's four major sea fish. The (annual) harvest was more than 10,000 metric tons for many years and it was a common dish," Yan Xiaojun, an ocean biologist from Zhejiang Ocean University, was quoted as saying. "Our generation has the responsibility and obligation to restore wild croaker resources."

Yan and his team chose an area near the Zhongjieshan archipelago as the base for preparing the fish for the wild.

If the croaker's survival rate was one in 100 then between 20 million and 200 million fry had to be released to meet the goal of 1,000 metric tons in three years, Yan said.

The team would begin by isolating an area of the sea with biodegradable nets where the fry would be regularly fed. The nets would keep big predators out but would allow smaller fish in, replenishing food supplies, Yan said.

Most of the yellow croakers (left) sold at market are farmed.
Most of the yellow croakers (left) sold at market are farmed.

While the croakers' swimming and hunting abilities would improve in this environment, the net would degrade within three to five months, giving the fish time to get used to the open sea.

Zhu Huatan, an inspector with Zhejiang's agriculture and rural affairs department, said preparing the fish was a difficult task because they took many years to mature.

Provincial authorities made similar efforts in 2003, but after several years there was no clear sign of a revival in the croaker population, Zhu told Xinhua. He said he was concerned about whether the project could meet the high expectations.

Lu Weiqun, a professor from Shanghai Ocean University, was also not optimistic. Xinhua quoted him as saying the croakers were not fast swimmers and he doubted that the fry released by humans could feed in the wild or escape predators.

Copyright (c) 2020. South China Morning Post Publishers Ltd. All rights reserved.

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