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Life cycle, growth, mortality and production of Ephemerella major Klapalek (Ephemeroptera) in a trout stream in Belgium
Author(s) -
ROSILLON DOMINIQUE
Publication year - 1986
Publication title -
freshwater biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 156
eISSN - 1365-2427
pISSN - 0046-5070
DOI - 10.1111/j.1365-2427.1986.tb00970.x
Subject(s) - nymph , trout , biology , zoology , ecology , fishery , fish <actinopterygii>
SUMMARY. 1. The life cycle of Ephemerella major Klapalek in a chalk trout stream in Belgium took 1 year. Emergence was highly synchronized with a flight period from mid‐May to mid‐June. Tiny nymphs occurred from June to late August. 2. The mean instantaneous growth rate was high in autumn (3.6% wet wt day −1 ), very low from November to February (0.8% wet wt day −1 ) and high until emergence (2.3% wet wt day −1 ); short day length seemed to be the major factor reducing growth rate during winter. 3. Mortality was close to zero during winter and 1.4—1.7% day −1 during other seasons. Total mortality from egg to adult was 99.6%. 4. The annual production was about 9g wet wt m −2 year −1 and the annual P/B̄ ratio was 7.5. There was good agreement between the production values estimated by four methods. Production rate was highest in May (13 mg wet wt m −2 day −1 ) and zero in February.