ID :
121546
Wed, 05/12/2010 - 08:42
Auther :
Shortlink :
https://www.oananews.org//node/121546
The shortlink copeid
Study shows steep drop in Pacific bluefin tuna
TOKYO, May 11 Kyodo - The population of large-sized Pacific bluefin tuna with reproductive capacity is shrinking at an alarming rate, in a sign they may face a crisis similar to the one their Atlantic peers are facing, according to a recent study by
Japanese researchers.
The results indicate the need to accelerate efforts to restrict the catch of
both the Atlantic and Pacific bluefin tuna, which are consumed in massive
numbers in Japan, for the protection of resources.
The study by a team led by Toshio Katsukawa, an associate professor and expert
on marine resources at Mie University, also showed that an overexploitation of
large-sized fish has led to a rise in the catch of juvenile small fish below 3
years or before egg production.
''It is imperative to suspend the catch during egg production periods and
reduce the capture of juvenile fish,'' Katsukawa said. ''If we wait to catch
them until they get bigger, the resources will recover and the revenue of
fishermen will also increase.''
Japan accounts for over 70 percent of the bluefin tuna caught in the Pacific,
of which about 55 percent are caught with encircling nets. In recent years, it
has also become popular to catch young fish and breed them.
According to estimates by Katsukawa based on the amount of fish caught with
encircling nets and the number being traded at Tokyo's Tsukiji fish market, the
average weight of bluefin tuna is around 50 kilograms, far lighter than the
average of 100 to 160 kg in the 1980s.
The proportion of bluefin tuna aged less than 1 year old among the fish caught
stood at around 60 percent during the 1960s, but climbed to over 70 percent
after 2000. More recently, the combined proportion of fish of less than 2 years
old has surpassed 90 percent.
The study shows the number of large fish aged 6 years or older that were caught
using the so-called pole-and-line fishing method has been dramatically
declining since 2004, while the catch of bluefin using encircling nets fell
sharply in 2009. The data reflect deterioration in marine resources, according
to the study.
Meanwhile, the average annual value of tuna aged less than 2 years stood at 2.7
billion yen on landing at ports between 2004 and 2008.
If the young fish are not caught until they reach 7 years old, the study
estimated, the average value will jump to 223.5 billion yen.
According to the Fisheries Agency, Japan caught about 17,800 tons of Pacific
bluefin tuna and imported about 3,800 tons in 2008, nearly equivalent to the
quantity of Atlantic bluefin tuna consumed in Japan.
==Kyodo
Japanese researchers.
The results indicate the need to accelerate efforts to restrict the catch of
both the Atlantic and Pacific bluefin tuna, which are consumed in massive
numbers in Japan, for the protection of resources.
The study by a team led by Toshio Katsukawa, an associate professor and expert
on marine resources at Mie University, also showed that an overexploitation of
large-sized fish has led to a rise in the catch of juvenile small fish below 3
years or before egg production.
''It is imperative to suspend the catch during egg production periods and
reduce the capture of juvenile fish,'' Katsukawa said. ''If we wait to catch
them until they get bigger, the resources will recover and the revenue of
fishermen will also increase.''
Japan accounts for over 70 percent of the bluefin tuna caught in the Pacific,
of which about 55 percent are caught with encircling nets. In recent years, it
has also become popular to catch young fish and breed them.
According to estimates by Katsukawa based on the amount of fish caught with
encircling nets and the number being traded at Tokyo's Tsukiji fish market, the
average weight of bluefin tuna is around 50 kilograms, far lighter than the
average of 100 to 160 kg in the 1980s.
The proportion of bluefin tuna aged less than 1 year old among the fish caught
stood at around 60 percent during the 1960s, but climbed to over 70 percent
after 2000. More recently, the combined proportion of fish of less than 2 years
old has surpassed 90 percent.
The study shows the number of large fish aged 6 years or older that were caught
using the so-called pole-and-line fishing method has been dramatically
declining since 2004, while the catch of bluefin using encircling nets fell
sharply in 2009. The data reflect deterioration in marine resources, according
to the study.
Meanwhile, the average annual value of tuna aged less than 2 years stood at 2.7
billion yen on landing at ports between 2004 and 2008.
If the young fish are not caught until they reach 7 years old, the study
estimated, the average value will jump to 223.5 billion yen.
According to the Fisheries Agency, Japan caught about 17,800 tons of Pacific
bluefin tuna and imported about 3,800 tons in 2008, nearly equivalent to the
quantity of Atlantic bluefin tuna consumed in Japan.
==Kyodo
