Low fish predation pressure in London reservoirs: II. Consequences to zooplankton community structure

✍ Scribed by Jaromir Sedal; Annie Duncan

• Book ID: 104613651
• Publisher: Springer
• Year: 1994
• Tongue: English
• Weight: 708 KB
• Volume: 291
• Category: Article
• ISSN: 1573-5141
• DOI: 10.1007/bf00014707

✦ Synopsis

The 1992 survey of zooplankton structure in fourteen London supply reservoirs showed the overall dominance of large-bodied zooplankton, mainly species of Daphnia . These reservoirs can be considered as 'anti-fish' by virtue of their steeply sloping concrete or brick sides . The average biomass of large Daphnia spp (retained on a 710 pm sieve) in the total zooplankton biomass was higher than 20% for twelve out of fourteen reservoirs . The cladoceran-copepod ratio was inversely correlated with both dominance of large-bodied Daphnia magna and cladoceran body-size structure . Parallelly, there were tendency of more efficient utilization of lowered algal crops in reservoirs dominated by large-bodied Daphnia spp .

A graphical model is presented which relates daphnid species composition and zooplankton size structure to a presumed gradient of fish biomass in these reservoirs .