水草种植模式对全雄中华绒螯蟹成蟹养殖性能和经济效益的影响

Effect of submerged macrophytes planting mode on performance and economic profit of all-male adult Eriocheir sinensis culture

  • 摘要: 中华绒螯蟹 (Eriocheir sinensis) 雌雄分养是一种新型的成蟹养殖模式,伊乐藻 (Elodea nuttallii)、轮叶黑藻 (Hydrilla verticillata) 和苦草 (Vallisneria natans) 是成蟹池塘养殖过程中的常用水草。为探索全雄成蟹池塘养殖条件下适宜的水草种植模式,比较了4种常见水草种植模式 单一伊乐藻、单一轮叶黑藻、伊乐藻∶轮叶黑藻 = 1∶1 (覆盖面积比)、伊乐藻∶轮叶黑藻∶苦草 = 1∶1∶1 (覆盖面积比),分别记为Mode I—IV 对中华绒螯蟹生长、性腺发育、养殖性能和经济效益的影响。结果表明:1) 4种水草种植模式对全雄成蟹养殖过程中的体质量无显著影响,但9—10月对4组蟹的体质量增长率和特定生长率有显著性差异,其中Mode I组最高,Mode II组最低 (P<0.05);2) 4组蟹的生殖蜕壳率、性腺指数和肝胰腺指数均无显著性差异 (P>0.05),8月底两种混合水草模式的蟹生殖蜕壳率略高于单一水草组,11月中旬Mode I组的肝胰腺指数和性腺指数均略高于其余组 (P>0.05),分别约为7.8%和3.3%;3) 在最终成蟹规格分布上,Mode I组大规格雄蟹 (≥250.0 g) 比例最低 (P>0.05),小规格雄蟹 (150.0~174.9 g和<150.0 g) 比例最高 (P<0.05)。4种水草种植模式下全雄中华绒螯蟹养殖成活率具有显著性差异 (P<0.05),Mode II和Mode III组的成活率和产量相对较高,且饲料系数相对较低;4) 在经济效益上,Mode II和III组的饲料投入相对较多,Mode II和Mode IV组的水草投入略多,Mode II组的总收入、净利润和投资回报率最高,Mode IV组最低。综上所述,全雄中华绒螯蟹成蟹池塘养殖过程中,种植轮叶黑藻 (Mode II) 或伊乐藻与轮叶黑藻混合种植模式 (Mode III) 可以提高成蟹养殖性能和经济效益。

     

    Abstract: The mono-sex culture of adult Chinese mitten crab (Eriocheir sinensis) is a new culture mode, and Elodea nuttallii, Hydrilla verticillata and Vallisneria natans are common submerged macrophytes in the adult E. sinensis aquaculture ponds. We investigated the effects of four planting modes (Mode I, single planting of E. nuttallii; Mode II, single planting of H. verticillata; Mode III, mixed planting of E. nuttallii and H. verticillata in equal proportions; Mode IV, mixed planting of E.nuttallii, H. verticillata and V. natans in equal proportions) on the growth, gonadal development, culture performance and profitability of all-male E. sinensis. The results show that: 1) There was no significant difference in the body mass among the four planting modes, but Mode I group had significantly higher weight gain rate (WGR) and specific growth rate (SGR) than the other groups from September to October, and Mode II had the lowest WGR and SGR (P<0.05). 2) Among the Mode I–IV, no significant difference was found in the puberty molting rate, gonadosomatic index (GSI) and hepatosomatic index (HSI) of adult male E. sinensis (P>0.05), and at the end of August, the puberty molting rate was slightly higher in mixed planting of E. nuttallii and H. verticilla than in the single submerged macrophyte group, while Mode I group had slightly higher HSI and GSI than the other groups at mid-November (P>0.05), reaching about 7.8% and 3.3%, respectively. 3) As for the size distribution of adult males, Mode I group had the lowest percentage of larger-sized males (≥250 g) and the highest percentage of smaller-sized males (150–174.9 g and <150 g). The survival rate of all-male adult E. sinensis was significantly correlated to the planting modes of submerged macrophytes (P<0.05), and Mode II and Mode III groups had higher survival rates and yields but lower feed conversion rates. 4) For the economic assessment, Mode II and Mode III groups had higher feed input, and Mode II and Mode IV groups had higher input of aquatic plant. Besides, the total return, net profit and return-on-investment (ROI) were highest in Mode II group but lowest in Mode IV group. In conclusion, planting H. verticillata (Mode II) or mixed planting of E. nuttallii and H. verticillata (Mode III) can improve the culture performance and economic profit of all-male adult E. sinensis.

     

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