Development of the Periphytic Community on Artificial Substrates in Fish Ponds

✍ Scribed by Dr. Ružena Markošová

• Publisher: John Wiley and Sons
• Year: 1979
• Tongue: English
• Weight: 653 KB
• Volume: 64
• Category: Article
• ISSN: 1434-2944
• DOI: 10.1002/iroh.19790640609

✦ Synopsis

The development of the periphytic algae and macrofauna was examined in two fish ponds. 43 genera of algae (mainly diatoms) were found on the substrates, and the maximum of algae was reached on the 10th day. The periphytic macrofauna consisted of 37 taxonomical groups (mainly Chironomidae). Larvae of Cricotopua interaectw were the most abundant species. Since the 2nd day of exposure, the number of Cricotopue larvae strongly increased by immigration of 2nd instars until the maximum was reached on the 15th day. No further significant oscillations were found in either the algal or animal component until the 75th day of exposure.

The field observations and laboratory experiments confirmed that:

(1) The distribution of frequencies of Cricotopua larvae found on 200 cm2 surfaces could be approximated by the normal distribution.

(2) The density of the algal periphyton is controlled by abiotic factors, not by grazing by chironomid larvae.

(3) The Cricotopus larvae of the 2nd instar colonize the substrate only after the algal film has been formed. Later instars are sedentary and do not colonize new substrate (except under stresa conditions).

(4) Food and predation do not seem to be the factors controlling the Cricotopus population density. The main factor is considered to be the territorial behaviour of the larvae.