Hidrológiai Közlöny 1982 (62. évfolyam)
6. szám - Ponyi Jenő–H. Péter Ilona–P. Zánkai Nóra: Az E. gracilis (G. O. Sars) (Copepoda, Calanoida) populációja szerkezetének és produkciójának naponkénti változásai nyáron a Balatonban
266 Hidrológiai Közlöny 1982. 6. sz. Ponyi, J.—H. Péter 1.—P. Zánkai N.: Az Eudiaptomus Junk by Publishers, The Hague —Boston —London, 281—335. [8] Ivanova, M. B. (1973): Estimation of accuracy for the calculation of production and elimination of planktonic crustaceans (Eudiaptomus gracilis) in the Lake Krasavitza taken as an example. — Zool. Zhur., 52, 111—120 (in Russian). [9] Janicki, A. J., J. DeCosta (1977): The effect of temperature and age structure on P/B for Bosmina longirostris in a small impoundment. — Hydrohiologia, 56, 11—16. [10] Kajak, Z., A. HillbricU-Ilkowska (eds) (1972): Productivity problems of freshwaters. — Warszawa — Krakow, PWN Polish Sei. Publish. 1—918. [11] Markewicz, J. C., G. E. Likens (1979): Structure and function of the Zooplankton community of Mirror Lake, New Hampshire. — Ecol. Monogr., 49, 109—127. [12] Mittelholzer, E. (1970): Populationsdynamik und Produktion des Zooplankton im Greifensee und in Vierwaldstältorsee. — Schweiz. Z. Hydrol., 32, 90—149. [13] Mullin, M. M., E. Ji. Brooks (1970): Production of the planctonie copcpod, Calanus helgolandicus. —- Bull. Scripps Inst. Oceanogr., 17, 89—103. [14] Pechen, G. A. (1965): The production of the cladoceran crustaceans in lake Zooplankton. — Gidrohiol. Zh. 1. 4, 19—26 (in Russian). [15] Peder son, G. L., E. B. Welch, A. H. Litt (1976): Plankton secondary productivity and biomass: their relation to lake trophic state. — Hidrobiologia, 50, 129—144. [16~\Petrova, M. A., T. S. Elagina, V. K. Spiridonov, T. A. FilatHna (1975): Production of planctonic Crustacea of two secondary oligotrophy lakes. — Gidrobiol. Zh., 11, 1, 82—86. [17] Ponyi, J. E. (1975): The biomass of Zooplankton in Lake Balaton. —Si imp. Biol. Hung., 15, 215—224. [ 18] Ponyi, J.. P.-Zánkai, N. (1980): Áz Eudiaptomus > gracilis (G. O. Sars) populációdinamizmusa, bioC ' masszája és biomassza produkciója a Balaton két f '— trofikus viszonyaiban eltérő vízterületen. — r ''Acta Biol. Debrecina, 17—-36. [19] Ponyi, J., Dominyák, I., A.-Rehák, M. (1980): Kísérlet egy folyamatosan szaporodó planktonrák (Eudiptomus gracilis, Copepoda) populációjának analíziséra, matematikai modell segítségével. — Kézirat, Tihany. [20] Sebestyén, 0. (1960): Horizontális planktonvizsgálalok a Balatonon. I. Tájékozódás a planktonrákok horizontális elterjedéséről — Annál. Biol. Tihany, 27, 115—130. [21] Shushkina, E. A. (1966): The ratio of production to biomass in lake Zooplankton. -— Gidrobiol. Zh., 2, 1, 27—35 (in Russian). [22] Weglenska, T. (1971): The influence of various concentrations of natural food on the development, fecundity and production of planktonic crustacean filtrators. — Ekol. Polska, 19, No. 30, 427—473. [23] Winberg , G. G„ G. A. Pechen, E. A. Shushkina (1965): Production of planktonic crustaceans in three lakes of different types. — Zool. Zhur., 5, 676—687 (in Russian). [24] Winberg, G. G. (ed.) (1971): Methods for the estimation of production of aquatic animals. — Acad. Press, London and New York, I —XII 4-1 — 175. [25] Zánkai, P. N. (1978): The duration of development of Eudiaptomus gracilis (G. O. Sars) (Copepoda) in Lake Balaton. — Acta Biol. Debrecina, Debrecen, Hungaria, 15, 183—198. [26] Zánkai, P. N. (1978): A balatoni Eudiaptomus gracilis (G. O. Sars, 1863) (Copepoda, Calanoida) táplálkozásbiológiájáról ós populációdinamizmusáról. — Kandidátusi értekezés, Tihany. Daily changes in population structure and production of Eudiaptomus gracilies (G. 0. Sars) (Copepoda, Calanoida) summer, in Lake Balaton Ponyi, J. Cand. Biol. Sei., —Mrs. Péter, I. H. and Mrs. N. P. Zánkai, Cand. Biol. Sei. In the years 1975 and 1977, the authors took samples every day for one month from Lake Balaton to study the population structure and primary production of Eudiaptomus gracilis (G. O. Surs). The main results are as follows: 1. Fecundity was different in summer during the two years studied. The average egg numbers per bag were 6.98 + 1.16 in 1975 and 10.68 + 1.42 in 1977. 2. The population contained 80 and 64 per cont larvae in 1975 and 1977, respectively. The ratios of males to females were 1 : 1,63 and 1 : 1.1 in the two years. 3. Close correlation existed in both series between thp egg number per litre and the total number of females (r= +0.88 and +0.86). 4. During the studies in 1975 they succeeded in tracing the development of 3, in 1977 of 4 cohorts. These took 19—20 days to develop in 1975, while 17—20 days in 1977. 5. According to estimates, in both study years 80—83 per cent of the nauplius larvae, while 12—15 per cent of the copepodit larvae eliminated. 6. The net biomass production per day was 6.88 mg dry weight/m 3 in 1975, while 1.94 mg dry weight/m 3 in 1977. The shares contributed to the daily production by the eggs, the nauplius- and copepodit larvae were 1 : 2.38 : 1.42 and 1 : 1.03 : 1.05 in 1975 and 1977, respectively. 7. In the two study periods the potential biomass productions per day Were 34.40 and 10.28 mg dry weight/m 3. The elimination in the given periods during the study years was 80 and 81 per cent by weight. 8. Based on net production figures, the P/B ratios were almost identical (0.120 and 0.099) in the two study periods. 9.Compared with 1975, the parameter values indicating the condition of the Eudiaptomus gracilis population changed by 1977. Fecundity increased, production diminished, while the rate of elimination and the P/B ratio remained unchanged. From the inconsistencies of the foregoing figures the authors have arrived at the conclusion that the consumption of Eudiaptomus by fish increased steeply. This is liable to result in a reduced population of the Copepod species, the only large-bodied filter in the lake, to bo replaced by another, smaller organism.