耐盐碱水稻–拟穴青蟹综合种养系统青蟹食物来源分析

ANALYSIS OF THE FOOD SOURCES OF MUD CRABS (SCYLLA PARAMAMOSAIN) IN THE SALT ALKALI TOLERANT RICE AND MUD CRABS CO-CULTURE SYSTEM

  • 摘要: 为了探究拟穴青蟹(Scylla paramamosain, 简称青蟹)在耐盐碱水稻–拟穴青蟹综合种养系统中的食物来源, 研究在耐盐碱水稻田内投放密度为0.6 ind./m2的拟穴青蟹, 经过为期2个月的养殖实验后通过碳、氮稳定同位素技术分析青蟹的食物来源。研究结果显示: 实验期间青蟹特定生长率为(2.71±0.27)%/d, 存活率为(14.26±4.85)%, 青蟹收获产量为(116.30±39.59) kg/ha, 水稻产量为3332.25 kg/ha。拟穴青蟹的δ13C为(–21.55±0.90)‰, δ15N为(9.96±0.40)‰, 可能食物源的δ13C为(–30.51±0.25)‰— (–13.45±0.15)‰。其中, 水花生的δ13C值最低(–30.51±0.25)‰, 其次是水稻(–28.73±0.73)‰, 而稗草的δ13C值最高(–13.45±0.15)‰。可能食物源的δ15N为(5.97±0.13)‰— (11.38±0.11)‰, 其中配合饲料的δ15N值最低(5.97±0.13)‰, 飞虫的δ15N值最高(11.38±0.11)‰。在食物贡献方面, 配合饲料对青蟹食物贡献最高, 达(61.2±3.8)%, 稗草和千金子次之, 分别为(8.3±5.2)%和(8.8±6.1)%, 飞虫的食物贡献率占比最低, 为(0.9±1.4)%。研究表明青蟹在耐盐碱水稻田内生长状况良好, 配合饲料可成为稻田内青蟹的主要食物来源, 同时植物性食物源对青蟹食物有重要贡献。研究可为耐盐碱水稻-青蟹综合种养系统管理和饲料开发提供理论和技术支撑。

     

    Abstract: The mud crab (Scylla paramamosain) is a marine species of significant economic value, renowned for its delicious flavor, strong adaptability, and rapid growth. As a euryhaline species, it demonstrates good tolerance to salinity and alkalinity after domestication. Salt-tolerant rice, also known as seawater rice, can grow in saline-alkaline soil and is characterized by its resistance to salt, alkali, flood, lodging, and pest. The integrated farming of salt-tolerant rice and mud crab, a new model that has emerged in recent years, enhances the economic output per unit area of paddy fields. In order to explore the food source of mud crabs in the salt alkali tolerant rice and mud crabs co-culture system, this study released mud crabs into a salt alkali-tolerant rice field at a density of 0.6 individuals per square meter. After a two-month breeding experiment, the food sources of mud crabs within this ecosystem were analyzed using carbon and nitrogen stable isotope technology. The research results showed that the water quality in the paddy field was promising. The mud crabs exhibited a specific growth rate of (2.71±0.27)%/d and a survival rate of (14.26±4.85)%, with mud crab yeild at (116.30±39.59) kg/ha and rice yield at 3332.25 kg/ha. The provision of compound feed to the crabs did not adversely affect water quality. In terms of isotopic composition, mud crabs displayed δ13C values of (–21.55±0.90)‰ and δ15N values of (9.96±0.40)‰. The potential food sources exhibited a range of δ13C values from (–30.51±0.25)‰ to (–13.45±0.15)‰. Among these sources, Alternanthera philoxeroides exhibited the lowest δ13C value at (–30.51±0.25)‰, followed by Oryza sativa at (–28.73±0.73)‰, while Echinochloa crus-galli exhibited the highest δ13C value at (–13.45±0.15)‰. Similarly, the potential food sources displayed δ15N values ranging from (5.97±0.13)‰ to (11.38±0.11)‰, with compound feed recording the lowest δ15N value at (5.97±0.13)‰ and flying insects the highest at (11.38±0.11)‰. The study found that compound feed constituted the primary dietary component for mud crabs, contributing (61.2±3.8)% to their diet. This was followed by contributions from Echinochloa crus-galli and Leptochloa chinensis at rates of (8.3±5.2)% and (8.8±6.1)%, respectively, while flying insects contributed the least, at only (0.9±1.4)%. In conclusion, the study suggests that mud crabs thrive in salt alkali-tolerant rice fields, with compound feed emerging as a significant food source for them within this environment. Additionally, plant-based food sources play a crucial role in the diet of mud crabs in such ecosystems.

     

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