Особенности сезонной динамики стада северного одноперого терпуга Pleurogrammus monopterygius Pallas в тихоокеанских водах у средних Курильских островов в 20022004 гг.

• Main Author: Ким, Сен
• Format: Text
• Language: unknown
• Published: Федеральное государственное унитарное предприятие «Тихоокеанский научно-исследовательский рыбохозяйственный центр» 2006
• Subjects: Atka; Middle Islands; Okhotsk; Pacific; okhotsk sea
• Online Access: http://cyberleninka.ru/article/n/osobennosti-sezonnoy-dinamiki-stada-severnogo-odnoperogo-terpuga-pleurogrammus-monopterygius-pallas-v-tihookeanskih-vodah-u-srednih; http://cyberleninka.ru/article_covers/5787855.png

Представлено пространственное распределение северного одноперого терпуга в водах средних островов Курильской гряды (о-ва Расшуа, Симушир и Кетой). Исследована размерная структура стада в весенне-летний и осенний периоды по данным 20022004 гг. Оценена биомасса рыб в преднерестовых и посленерестовых нагульных скоплениях терпуга у исследуемых островов. Показано, что динамика уловов и размерного состава рыб в районе укладывается в общую схему сезонных миграций терпуга в водах северных Курильских островов. Seasonal aspects of biology and spatial distribution of atka mackerel in the Pacific waters off middle Kuril Islands are considered for summer-autumn period of 20022004 (May-June in 2002, October-December in 20032004). The spatial-temporal dynamics of the atka mackerel stock in the waters at Kuril Islands is determined by ontogenetic changes of their fry and seasonal migrations of adults. The whole area of atka mackerel distribution covers the vast region of the Okhotsk Sea and North-West Pacific adjoining the Kurils, but adults of atka mackerel supposedly migrate to the middle islands of Kuril ridge for wintering. Main concentrations of atka mackerel form usually over shelf and upper slope in the layer 140200 m with the temperature 1.64.7 °C. In 2004 and 2003, they were caught mainly off Rashua Island, but in 2002 during a short period in the Diana Strait between Simushir and Kaetoi Islands. The average CPUE was 11.1 t in 2002, 20.0 t in 2003, and 11.6 t in 2004. The catches increased sharply in October to November. Besides, the CPUE and fish concentrations density had twenty-days periodicity in 2004. The autumnal increasing associated with the increasing of males number after completing their spawning. Females dominate in prespawning aggregations: the ratio females/males was 1 : 0.72 in May-June of 2002; but males dominate in autumn (up to 71 % in 2004), and their share decreases again only in December (in 2003) or late November (in 2004). Size structure of the atka mackerel changed sharply year-to-yearly. In 2003, the dominant group had the length 2529 cm and represented the year 1999 generation. To 2004, this group of fry had grown up to 3234 cm and formed good recruitment for the spawning stock. Now this generation is the base of regional fishery. Biomass of the atka mackerel within the aggregations at the middle Kuriles was estimated as 10,600 tons per the square 81 miles2 in 2002 and 5,200 tons per the square 37 miles2 in 2004. Meanwhile, the mean total stock of atka mackerel in the waters at Kuril Islands in 1990s was about 39,000 tons, and its maximal value in 19992000 was estimated as 125179 thousand tons. Thus, the stocks surveyed in 20022004 could not represent the whole wintering stock, so the wintering is possibly goes in other areas, too. However, new data on distribution and catch dynamics off the middle Kurils obtained in 20022004 do not deny the hypothesis about prewintering migrations of the atka mackerel to the area of Rashua-Simushir Islands. Undoubtedly, large wintering aggregations of adult fish form here in autumn, and probably they remain the same location in winter.