稻虾田黄鳝的食物组成及其对克氏原螯虾捕食强度研究

文章研究了稻田黄鳝(Monopterus albus)天然饵料生物资源、稻田黄鳝对克氏原螯虾(Procambarus clarkii)捕食选择及不同投喂策略下黄鳝对克氏原螯虾的捕食强度,旨在为构建与优化稻-虾-鳝综合种养模式提供依据。结果表明,稻田中黄鳝天然饵料生物种类丰富,达16种(属);克氏原螯虾是黄鳝最喜猎物,其次为米虾,再次为蚯蚓和水生寡毛类;稻田黄鳝自然生长期间,其胃和肠前端食物团中,克氏原螯虾重量百分比均显著高于其他猎物,其中8月份占比最大,达93.90%, 4月份占比最小,为76.85%;当克氏原螯虾为唯一食物时,每尾大规格成鳝(≥200 g)日均捕食量为(1.63±0.065) g;当克氏原螯虾、米虾和蚯蚓作为食物时,黄鳝主要捕食克氏原螯虾且不捕食蚯蚓,对三者的选择指数分别为0.066、–0.266和–1;若以克氏原螯虾、鱼糜-饲料为食物时,黄鳝主要摄食鱼糜-饲料,极少捕食克氏原螯虾,对两者的选择指数分别为–0.846和0.591。

FOOD COMPOSITION OF RICE FIELD EELS AND PREDATION INTENSITY ON CRAYFISH

Rice-crayfih-eel co-culture is a high benefit comprehensive culture model that integrating rice planting, crayfish and eel cultivation. However, study on the predatory relationship between eel and crayfish is lacking, which is one of the key issues related to the establishment of this model. This study explored the potential food organisms and food composition of eel in rice-crayfish fields and its predation selection for crayfish by investigating the resources of macroorganisms and benthos and analyzing the gastrointestinal contents of eel in rice crayfish fields. The results showed that the natural bait for rice field eels was abundant in the paddy field environment, a total of 16 genera of basic bait organisms were found. Crayfish was the most preferred prey for eel, followed by caridina, earthworms and aquatic oligochaetes. The percentage of crayfish in the food mass of rice field eels was the highest from April to August, with a maximum of 93.90% in August, and a minimum of (76.85±20.66)% in April. When crayfish was the only food, the average daily predation of each large-size eel (≥200 g) was (1.63±0.065) g; when crayfish, caridina and earthworms were used as food, the rice field eels mainly fed on crayfish and did not feed on earthworms with the selection indices were 0.066, –0.266 and –1.000, respectively, When the live crayfish and feed (fresh surimi and crayfish artificial compound) were used as food, the rice field eels were mainly fed on feed but not on crayfish with the selection indices were –0.846 and 0.591, respectively. The results of this study provide a theoretical basis for the establishment of rice-crayfish-eel co-culture model and reasonable stocking of eel under this model.