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根据2008年1月—2017年6月在大连海域收集的因搁浅、误捕及救助无效而死亡的斑海豹、江豚、小须鲸等海洋哺乳动物及2016年秋季和2017年春季在该海域进行的渔业资源调查,应用稳定同位素技术,分析了大连海域海洋哺乳动物及主要生物样品的碳、氮稳定同位素比值(δ13C、δ15N),并计算其营养级,进而构建大连海域食物网的连续营养谱。结果表明:大连海域食物网的δ15N值范围为7.97‰~14.65‰,δ13C值范围为-21.11‰~-16.73‰。主要生物种类可划分为初级消费者、次级消费者及顶级捕食者3个营养组群。δ15N值分析显示,主要生物种类的营养级范围为2.63~4.59,其中,小须鲸、江豚、斑海豹的营养级依次为3.16、4.11、4.25,棘皮动物为3.24~3.84,头足类为3.81~3.93,腹足类为3.65~4.13,双壳类为2.63~3.15,甲壳类为3.58~4.12,鱼类为3.20~4.59。营养结构特征显示,初级消费者主要为双壳类,次级消费者主要为小须鲸、头足类、棘皮类、腹足类、甲壳类,顶级捕食者主要为江豚、斑海豹、鱼类。随着江豚体长的增加,δ15N值有相应增大趋势,说明随着江豚生长和摄食能力的增强,其摄食的食物趋向于更高营养层次的生物,研究建立了大连海域食物网的连续营养谱,可以为海洋哺乳动物和渔业资源的保护提供依据。
According to the marine mammals such as harbor seal, finless porpoise and minke whale that have been collected in Dalian sea area from January 2008 to June 2017 and died as a result of stranded, inadvertent and rescue invalids, and in the autumn of 2016 and spring of 2017 in the area Based on the investigation of fishery resources, the stable isotope ratios of carbon and nitrogen (δ13C, δ15N) of marine mammals and major biological samples in Dalian area were analyzed and their trophic levels were calculated by using stable isotope techniques. Thus, the continuous nutrient spectrum of Dalian food webs was constructed. The results showed that the δ15N values of food webs in Dalian area ranged from 7.97 ‰ to 14.65 ‰ and the δ13C values ranged from -21.11 ‰ to -16.73 ‰. The main biological species can be divided into three groups of primary consumers, secondary consumers and top predators. δ15N value analysis showed that the trophic levels of the major species ranged from 2.63 to 4.59, among which, the trophic levels of minke whales, finless porpoises and harbor seals were 3.16, 4.11 and 4.25 respectively, while that of echinoderms was 3.24 to 3.84 and that of cephalopods was 3.81 ~ 3.93, gastropods from 3.65 to 4.13, bivalves from 2.63 to 3.15, crustaceans from 3.58 to 4.12, and fish from 3.20 to 4.59. The nutritional structure shows that the primary consumers are mainly bivalves, the secondary consumers are minke whales, cephalopods, echinoderms, gastropods and crustaceans. The top predators are finless porpoises, harbor seals, and fish. With the increase of body length of finless porpoise, the δ15N value increased correspondingly, indicating that the food intake of finless porpoise tended to be higher in nutrient level as the growth and feeding capacity of finless porpoise increased. The continuous nutrition of Dalian food web was established Spectrum, can provide the basis for the protection of marine mammals and fishery resources.