光倒刺鲃、白鲢协同投放抑制丝状藻(水绵)藻华围隔研究

为探究高效与安全抑制丝状藻藻华的方法,利用光倒刺鲃(Spinibarbus hollandi)、白鲢(Hypophthalmichthys molitrix)的食性特点,研究了不同密度(低密度(L)40 g·m-3、高密度(H)80 g·m-3)与不同投放比例(光倒刺鲃∶白鲢=3∶1、1∶1、1∶3)协同作用下,对围隔内水体丝状藻水绵(Spirogyra sp.)的抑制效果,以及对水生植物和水质的影响.结果表明,光倒刺鲃可以显著摄食丝状藻水绵,且在低密度、高比例(3∶1)时,即对丝状藻的生长具有明显抑制作用.高密度(80 g·m-3)投放光倒刺鲃、白鲢,无论比例如何,都会引起水体水质下降,引起轻微富营养化,并导致浮游藻类生物量上升,不适用于本试验水体.在本试验条件下,高密度(80 g·m-3)投放条件下,白鲢可以抑制浮游生物总量,H(1∶3)、H(1∶1)组中,呈现藻类小型化的趋势;而在低密度(40 g·m-3)投放条件下,未发现浮游藻类有小型化趋势.本试验L(3∶1)组,即光倒刺鲃30 g·m-3、白鲢10 g·m-3,可以有效控制试验水体丝状藻水绵滋生,且能够兼顾改善水质.

Enclosures experiment for controlling filamentous algae (Spirogyras sp.) by Spinibarbus hollandi and Hypophthalmichthys molitrix

In this paper, the inhibition of filamentous algae (Spirogyra sp.) and the synergistic effect of submerged plants and water quality in the enclosures for two species fishes with different ratios (3:1, 1:1, 1:3;S. hollandi: H. molitrix) and densities (40,80 g·m^-3) were studied by feeding characteristics of S. hollandi and H. molitrix to find out an efficient and safe way for controlling filamentous algae. The results showed that,the filamentous algae could be significantly inhibited in the low density group of S. hollandi with higher ratio (L,3:1). While, in S.hollandi high density (80 g·m^-3) group with any ratio, water quality would decrease and water were light eutrophic, and biomass of phytoplankton increased. In the higher density group (80 g·m^-3), H. molitrix could inhibit the biomass of the phytoplankton, and in the groups with the ratios (1:3; 1:1), the phenomenon of miniaturization of the phytoplankton was found. While in the low density group (40 g·m^-3), the phenomenon of miniaturization of the phytoplankton was not found. In conclusion, the fishes in low density group with the ratio of 3:1 (S. hollandi: H. molitrix) could significantly inhibit the filamentous algae (Spirogyra) and were beneficial to improvement of water environment.