Effect of Dreissena mussels on the distribution of zooplankton as exemplified by the Main Kakhovka Canal

Technical Report · Thu Jun 01 04:00:00 EDT 1995

OSTI ID:146957

Grigorovich, I A; Shevtsova, L V ^[1]

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1. National Ukrainian Academy of Sciences, Kiev (Ukraine)

In summer the abundance of zooplankton in the Main Kakhovka Canal varied in the range of 1,500-18,500 indiv.m{sup -3}, with a biomass of 15-240 mg m{sup -3}. From the upper reach of the canal to the end, the zooplankton become less diverse and there is a decrease in both abundance and biomass. In the initial sections of the canal, copepods predominated, owing to their considerable influxes from other sources, i.e., Kakhovka Reservoir. Whereas in the second half of the canal, the dominant complexes of zooplankton changed and consisted primarily of cladocerans and Dreissena veligers. With high abundance of Dreissena polymorpha (Pallas) and D. bugensis (Andrusov) (mean biomass was 4.2 kg m{sup -2}), with the maximum ca. 17.8 kg m{sup -2}, mussels had a significant effect on the spatial distribution of planktonic invertebrates. In different areas of the canal the measurable quantitive replenishment of zooplankton was proceeded by planktonic larvae of Dreissena. Being active filterers, Dreissena mollusks undermine food resources of filter-feeding zooplankton by accelerating sedimentation of suspended matter, including organic substances, by a factor of 1.4-3.0. Dreissena can control zooplankton density by consumption of some of the species. With predominating rotifers and juveniles cladocerans in the plankton, the total abundance of zooplankton influenced by Dreissena bugensis had decreased by 53% after 12 h, whereas the amount of dominant species, Euchlanis dilatata and Bosmina longirostris, had declined respectively by 92% and 64%. Dreissena individuals 14-18 mm long, are the predominant size group of mussels in the Main Kakhovka Canal and can filter off planktonic invertebrates with body lengths between 20 and 400 m. Zooplankton species of such size can pass through the bronchial siphon of Dreissena and so they are vulnerable to consumption by mussels. There is an inverse relationship between the biomass of zooplankton and the biomass of adult Dreissena mussels.

• Research Organization: Electric Power Research Inst., Palo Alto, CA (United States)
• OSTI ID: 146957
• Report Number(s): EPRI-TR--105116; CONF-9502124--
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
55 BIOLOGY AND MEDICINE
BASIC STUDIES
BENTHOS
BIOLOGICAL FOULING
CONTROL
DIAGRAMS
INLAND WATERWAYS
MUSSELS
NUMERICAL DATA
UKRAINE