Biological characteristics of Sardinops sagax in high seas of the northwest Pacific Ocean
Japanese sardine is a small warm-temperate pelagic fish with strong clustering in the Northwest Pacific Ocean,and is the main commercially fished species in countries along the Northwest Pacific Ocean.In recent years,China's pelagic fisheries in high seas of the Northwest Pacific Ocean have developed steadily.Historically,the proposed sardine fishery in the Far East has undergone several major changes,its production is highly unstable and its resources are highly vulnerable to the effects of global climate change.As the fishing production of Japanese sardine has increased year by year in recent years,the North Pacific Fisheries Commission(NPFC)has listed it as a priority species for assessment and is preparing to carry out its resource assessment and management.The biological characteristics of Japanese sardine in the North Pacific Ocean are of great importance to improve the fishing efficiency and scientific management of high seas fisheries in the North Pacific Ocean.Japanese sardine(Sardinops sagax)is one of the main species caught in high seas purse seine fishery in the Northwest Pacific Ocean.Based on samples collected during April-December 2020 and April-November 2021(a total of 2 664 fish),measurement of biological indicators were made,including fork length(L),body mass(W),feeding intensity(F),sex(S),and gonadal maturity.The basic biological characteristics such as population structure,gonadal maturity,initial sexual maturity fork length,feeding class,and fatness were studied.The results showed that the fork length of Sardinope sagax ranged from 85 mm to 240 mm,the dominant fork length group was from 160 mm to 200 mm,and the fork length of individuals of different sexes did not differ significantly(P＞0.05);the body mass ranged from 5.6 g to 144.6 g;the dominant body mass group was from 35 g to 75 g;the body mass of individuals of different sexes did not differ significantly(P＞0.05);the age group became 0+-6+;the dominant age group was 1+-3+.The relationship between fork length and body mass was in accordance with the power function exponential equation,and the growth parameter b=3.153 8 was consistent with positive anisotropic growth.Sexual maturity was predominantly staged Ⅱ(more than 90％),with highly significant differences(P＜0.01)between the gonadal maturity of 95-104 mm and 105-114 mm fish in the fork length group.The difference in sexual maturity between 205-224 mm and 225-245 mm fork length groups was significant(P＜0.05);the initial sexual maturity fork length(L50)was 178.1 mm.Feeding intensity was mainly 0-2 levels,and the difference in feeding intensity between fork length groups was significant(P＜0.05).The study enriched the basic information on the biological characteristics of Sardinops sagax in the Northwest Pacific Ocean,including the recent age structure of its population,fork length range,dominant fork length group,body mass range,dominant body mass group,sexual maturity,feeding intensity of different fork length groups with different months,fertility coefficient of different fork length groups with different months,and also fitted the growth equation of Sardinops sagax,etc.The findings of the study can provide an important basis for its population identification,life history study,resource development and rational utilization,etc.
万方数据
维普
