Analysis on factors influencing energy density in muscle of Gadus chalcogrammus in the western Bering Sea
Walleye pollock(Gadus chalcogrammus)is a kind of deep-sea,cold-water demersal fish.It is one of the most productive species in global fisheries and has extremely abundant resources.G.chalcogrammus is mainly distributed in the subarctic waters of the north Pacific,and its habitat spans a maximum of more than 1 200 m,concentrating in the water layer from 50 m to 300 m,and water temperature from 1 ℃ to 10 ℃.G.chalcogrammus is a key species in the Bering Sea,mainly feeding on small fish,krill and zooplankton.Energy accumulation and variation can numerically visualize the physiological changes in life stages of organisms and is one of the factors for species to make adaptive decisions according to their environments.Therefore,conducting studies on energy density in fish tissues can help researchers to understand their physiological development.In order to understand the changes in energy of muscle tissues during the growth and development of G.chalcogrammus in the Bering Sea,112 samples collected in 2019 and 2020 were used to measure the energy density of muscle tissues for G.chalcogrammus.The energy accumulation and changes of individual muscle tissue of G.chalcogrammus in summer were analyzed by generalized additive model(GAM),and factors influencing the variation in energy density were further explored.The results showed that the energy density of muscle tissues for G.chalcogrammus with standard length of 23.8-60.5 cm was(21.10±0.89)kJ·g-1,and there was no significant difference in energy density of muscle tissues between years.GAM results explained 46.1％deviation of energy density of muscle tissues in G.chalcogrammus,and both gonad weight and month were two factors that significantly affected the energy density of muscle tissues,while other factors,including standard length,sex and sexual maturity,did not show significant effects on the energy density of muscle tissues.The energy density of muscle tissue increased from June and reached the peak in August and then decreased in September.Compared with sexual maturity,gonad weight was more suitable to be used as the reproductive indicator to analyze the factors influencing energy density of muscle tissues.The significant effect on the accumulation of energy density in muscle tissues was caused by gonad weight rather than gonad maturity.Results showed that there was no significant inter-annual rariation in energy density in muscle tissues of G.chalcogrammus between 2019 and 2020.The energy density in tissues from different organs of G.chalcogrammus gradually changed with its growth and development,and was influenced by a combination of intrinsic and extrinsic factors.The muscles of G.chalcogrammus were one of the main organs for storing energy.Changes in the energy density of muscle tissues had an important influence on the distribution of individual energy and they were one of the characteristics that affected the fishing yield.Individual fish had different criteria for the overall energy distribution at different stages of growth and development.During spawning,the energy density in gonad tissue of G.chalcogrammus increased due to certain changes in the structure and material composition of the gonads.Therefore,there were certain fluctuations in energy density of G.chalcogrammus gonad tissue during its reproduction,and muscles also allocated energy in tissue at different life history stages and this led to corresponding changes in energy density of muscle tissues.The standard length also did not influence energy density of muscle tissues in this study,which might indicate that the cumulative effect of standard length on the energy of G.chalcogrammus muscle tissues was less important compared with indicators reflecting reproductive activity.According to different life characteristics of aquatic animals,the corresponding reproductive strategies and energy allocation principles also differed,and the energy allocation strategies of G.chalcogrammus reproductive stages were also related to their life characteristics.In summary,this study suggests that the analysis of the factors affecting energy accumulation and energy density should be performed with multivariate statistical methods to better reveal the main factors affecting energy density of animals.
Gadus chalcogrammusenergy accumulationBering SeareproductiongrowthGAM
万方数据
维普
