Abstract
The effects of periphyton grown on bamboo substrate, on growth and production of Nile tilapia, Oreochromis niloticus (Genetically Improved Farmed Tilapia strain) in monoculture and polyculture with the freshwater prawn (Macrobrachium
rosenbergii) were studied and economically evaluated. The experiment had 2×2 factorial design: The first factor was presence or absence of substrate for periphyton development, the second factor was related to culture system. The first system was monoculture of the GIFT strain of Nile tilapia stocked at 20,000 fingerlings ha−1, the second system was Design of sampling programmes: “begin with the end in mind” ......................................... 3
2.1 Introduction ........................................................................................................................... 3
2.2 Types of sampling programmes ......................................................................................... 3
2.3 Defining your objectives ...................................................................................................... 3
2.4 Issues of scale ........................................................................................................................ 5
2.5 Examples of setting objectives and carrying out a sampling programme ................... 6
2.6 Reference sites ..................................................................................................................... 12
2.7 Maximising information for the available budget ......................................................... 13
3 Determining data precision and number of sampling replicates required ........................ 16
3.1 Background .......................................................................................................................... 16
3.2 Measures of variability ...................................................................................................... 17
3.3 Estimating the number of replicate samples needed for general
resource surveys ................................................................................................................. 17
3.4 Estimating the number of replicate samples required for testing hypotheses
of differences in two population means for periphyton biomonitoring and
consent evaluation .............................................................................................................. 20
3.5 Estimating number of replicate samples required for testing hypotheses
regarding compliance with periphyton cover or biomass guidelines ........................ 22
3.6 Stratifying sampling effort to increase precision and reduce effort ............................ 24
3.7 Estimating the number of replicate samples required and level of
differences in testing effects: a cautionary note .............................................................. 25
4 Specific considerations in planning studies ............................................................................. 26
4.1 Resource surveys ................................................................................................................ 26
4.2 Impact assessments ............................................................................................................ 28
4.3 State of the Environment monitoring .............................................................................. 31
4.4 Some practical considerations before you start your study ......................................... 33
5 Common New Zealand stream habitats and their periphyton communities .................... 34
5.1 Spring-fed streams .............................................................................................................. 34
5.2 Lake-fed streams ................................................................................................................. 34
5.3 Wetland-fed streams ........................................................................................................... 35
5.4 Low-altitude streams.......................................................................................................... 35
iv
Stream Periphyton Monitoring Manual
5.5