A pilot project on intermittent harvesting is proposed which will aim at:
documenting the occurrence of the strategy in selected areas
investigating and documenting the advantages and disadvantages of the strategy for the farmer with regard to social, economic, nutritional, technical and biological factors
developing and demonstrating means for improved harvesting strategies
The main activities for the pilot project are envisaged to be:
surveys/in-depth studies on the occurrence and reasons for inter-mittent harvesting
monitoring of yields, income and protein availability under different harvesting strategies
a bio-technical simulation model
investigations of the bio-technical aspects of intermittent harvesting strategies
technical consultation on intermittent harvesting
introduction, testing and monitoring impacts of improved production and harvesting strategies for small-scale farmers on yields, income and protein availability.
Pilot project activities will be carried out using the following methods:
desk studies
field surveys and in-depth studies
on-station applied research/trials
on-farm trials
The results of the desk studies, field surveys and studies will be synthesized in order to help determine the detailed workplan used for the on-station applied research and on-farm trials.
Luapula Province in Zambia and Murewa District in Zimbabwe were chosen as areas suitable for the initiation of main pilot activities on socio-economic aspects of intermittent harvesting strategies (activities 1 and 2) and on-farm trials (activity 5) because they fulfilled the following criteria:
large number of active fish farmers
fish farmers not widely dispersed
both established and new farmers
year round availability of water
intermittent and/or incomplete/complete batch harvesting is practised
ALCOM may initiate other pilot activities in these areas.
The significant difference between the two areas is that different pond drainage systems are in practice. In Murewa District (Zimbabwe) all ponds are undrainable, while in Luapula Province (Zambia), most of the ponds are drainable.
It is also envisaged that investigations on harvesting strategies can be included as part of the selected socio-economic studies on fish farmers. Selected activities will be undertaken in North-Western Province, Zambia by ALCOM and by NORAD Fish Culture Development Project in Northern Province, Zambia.
Possible sites for on-station research as proposed in activity 4 are the Henderson Aquaculture Station, Zimbabwe and the Fiyongoli Fish Culture Station in Luapula Province, Zambia.
Close contacts should be maintained to coordinate activities with other aquaculture research and/or extension programmes including:
FAO/Netherlands Development of Fish Culture in Zambia, Project GCP/ZAM/038/NET
ICLARM/Malawi Aquaculture Project
NORAD/GRZ Aquaculture Development Project in Northern Province, Zambia
FAO/TCP Project, Support for Rural Aquaculture: Rehabilitation of the Henderson Aquaculture Farm, Zimbabwe
Work plans for activities to be undertaken in each selected area are detailed below. Suggested time schedules for each activity are attached as appendix 7.
Objective
To document the occurrence and reasons for intermittent harvesting in selected areas.
Protocols.
A. LUAPULA PROVINCE, ZAMBIA
In-depth Case Studies (using informal interviews) on households selected from a stratified random sample of practising fish farming households interviewed (i.e. the population) during the ALCOM socio-economic survey of the province. Selection of sample size and strata should be made once the results of the socio-economic survey are available. The quality of these results will determine which criteria are selected for stratification. One possible method would be to classify farmers according to the critical resources under the control of the household, a system used by ARPT in Northern Province (see Bolt and Silavwe, 1988). The number of strata should not exceed half the sample size and the sample size should be at least 30% of the total sample of surveyed fish farmers. The strata should aim to maximize variation between groups and minimize variation within groups.
The case studies should aim to collect information on the relation of fish farming to the overall socio-economic activities of the households, the type of farming systems practised (linked to ARPT definitions for the province), availability and allocation of resources, nutritional and cash requirements during the agriculture year, reasons farmers give for practising their harvesting strategies and techniques used. The household head as well as other adult members should be interviewed.
Staff. ALCOM Socio-economist and one interpreter
Duration: 6 weeks plus 2 weeks report writing
B. MUREWA DISTRICT, ZIMBABWE
Because little data exists on fish farmers in Zimbabwe, it is proposed that an initial preparatory phase with the objective of collecting baseline socio-economic data on fish farmers in Murewa District is undertaken before in-depth case studies on intermittent harvesting are initiated.
PREPARATORY PHASE
(i) Brief formal census to collect baseline data on all former and practising fish farmers in the area: name, age and sex of fish farmers, household size, location, main economic activities, farm holding size and number of ponds.
Staff: 2 enumerators supervised by ALCOM Socio-economist
Duration: 4 weeks, including report writing
(ii) Socio-economic survey of a random sample (15–20%) of fish farming households using methodology developed by ALCOM in Zambia. Survey questionnaire to be adapted to local conditions.
Staff: ALCOM Socio-economist, ALCOM Aquaculturist, two enumerators/ interpreters.
Duration: 8 weeks (survey, input and analysis of data).
PHASE I
In-depth case studies on harvesting strategies and methodology used for sample selection as for Luapula Province. Types of farming systems can be linked to AGRITEX definitions.
Staff: ALCOM Socio-economist
Druation: 6 weeks plus 2 weeks report writing
C. NORTH-WESTERN PROVINCE, ZAMBIA
As part of the follow-up activities of the socio-economic survey undertaken by ALCOM in this province, protocols are being prepared for further in-depth studies on selected fish farming households to be undertaken by an ALCOM Socio-economist (APO) in the first half of 1989. Investigations of different harvesting strategies should be included as a component of these studies.
D. NORTHERN PROVINCE, ZAMBIA
NORAD/GRZ have recently begun a fish culture development project in this province. Part of the project activities will be to establish a baseline data collection and monitoring system to collect information on fish farmers. Also planned are in-depth studies on food intake, nutritional status, household size and allocation of resources. Adaptive research on different production strategies will be conducted with selected fish farming households. It is proposed that ALCOM establish close links with the NORAD project to enable information exchange on research undertaken.
Objectives
To investigate yields, income and protein availability under different harvesting strategies.
To provide information for on-station applied research.
Protocols (Luapula Province and Murewa District)
Monitoring twice a month, a total of 15–20 fish farming households in each area that undertake different harvesting strategies. Some households may be selected from Activity 1 and from the ALCOM socio-economic survey. Where applicable* basic socio-economic data about the household should be collected before monitoring commences.
Data collected for monitoring purposes should include: frequency, quantity and size of fish harvested; costs of inputs and outputs, destination of fish (e.g. household consumption, sale, payment for labour), protein intake of households, fishing effort, stocking densities and methods.
Staff: ALCOM Socio-economist or Aquaculturist, two enumerators.
Druation: 12–18 months
Objective
To investigate interactions between biotic and a-biotic factors controlling production simulating different harvesting strategies and environmental conditions.
Protocol
PHASE I
A desk study will establish a frame work simulation model including the biological, technical and management aspects of intermittent harvesting strategies from available literature.
PHASE II
Inclusion of results from on-station applied research and trials (see 3.5.4) in order to develop the simulation model. The possibility of incorporating economic data from the surveys and/or studies should be investigated.
Staff: ALCOM Aquaculturist (APO): Phase I
ALCOM Aquaculturist and Socio-economist: Phase II.
Duration: 8 weeks: Phase I
8 weeks: Phase II
Equipment: Computer
Objectives
To investigate biological and technical aspects of intermittent harvesting strategies aiming to improve production and harvesting techniques for small-scale tilapia farmers.
Protocols
The proposed applied research/trials are based on the following assumption:
application of simple techniques
self-production of fingerlings (if needed)
minimization of cash inputs
maximization of self-reliance.
Based on the facilities available for trials as well as the nature of pilot project activities, the proposed applied research may be characterized as empirical investigations rather than as academic research.
Two main activities to be undertaken at government fish culture stations are proposed:
PHASE I
Testing the growth potential of tilapia strains used by small-scale fish farmers practising intermittent harvesting strategies.
PHASE II
Testing different harvesting strategies under production conditions similar to those of the small-scale fish farmers.
PHASE I: Testing growth potential of local fingerlings
The aim of this experiment is to investigate the growth potential of rural tilapia fingerlings reared under different harvesting strategies for at least three years. The growth potential may be an indication of the occurrence (and possibly, degree) of inbreeding and/or effects of environmental factors controlling growth. All growth parameters should be considered.
These investigations are essential for the final design of the second phase.
Groups of fingerlings from different types of harvesting strategies practised in the area and/or from farms under different environmental conditions should be pooled (fingerlings from 5–10 farmers per group) and tested in small ponds or aquaria (if available). Three possible groups and a control group to be tested are:
fingerlings from farmers practising incomplete batch harvesting but no intermittent harvest
fingerlings from farmers practising intermittent harvesting and incomplete batch harvest
fingerlings from farmers practising only intermittent harvesting
control group: local strains from a Government Station or from river systems
Staff: National Aquaculturist in collaboration with ALCOM Aquaculturist
Duration: 3–4 months
PHASE II: Intermittent harvesting strategies
The aim of this experiment is to investigate the production potential under different intermittent harvesting strategies. Although an experimental framework is proposed here, the final design will incorporate preliminary results from socio-economic studies (activity 1), data from monitoring of different harvesting strategies (activity 2), the interactions elucidated by the simulation model (activity 3) and phase I of this activity. Special attention should be given to the:
time interval between two intermittent harvests
quantity of fish to harvest
quantity of each size class to harvest
techniques of harvesting fish
Four different harvesting strategies are likely to be undertaken with mixed sex culture of O. andersonii (or T. rendalli or T. machrochir) in Zambia and O. mossambicus in Zimbabwe (if possible with new, pure strains collected from the wild). The production technique used should be based on the inputs available to local small-scale farmers i.e. fertilization through a compost crib (household leftovers, green manure, animal droppings), ash liming and feeding with green feeders (leaves) and locally available maize or rice bran. Land-based compost can be tested as an alternative for the compost crib. The proposed strategies are:
standard culture technique plus intermittent harvest
stocking density: 2 fingerlings/m2
culture period: 6–8 months
selective intermittent harvest after 2–3 months (only “big” fish)
complete batch harvest
restocking
Extended culture period with intermittent harvesting plus complete batch harvest
stocking density: 2 fingerlings/m2
culture period: 1 or 2 years (will be determined according to the degree of in-breeding)
selective intermittent harvesting after 3–4 months (all size classes)
complete batch harvest
restocking
Extended culture period with intermittent harvesting plus incomplete batch harvest
stocking density: 2 fingerlings/m2
culture period: indefinite
selective intermittent harvest (all size classes)
no restocking
Standard technique
stocking: 2 fingerlings/m2
no intermittent harvest
culture period: 6–8 months
complete batch harvest
restocking
The most important parameters to be investigated are net production, number and size of fish. Monitoring of population dynamics, breeding frequencies, number of offspring per batch and a-biotic factors controlling production are essential. The occurrence and degree of inbreeding of fingerlings produced under these “controlled” different strategies should be investigated yearly, (as in phase I).
Killing of remaining fry/fingerlings with a natural poison (e.g. rotenon) is a prerequisite for a complete batch harvest for undrainable ponds (Zimbabwe). Rotation culture with monosex tilapia may alternatively be tested.
Other factors controlling production such as stocking densities and feeding regimes, as well as tilapia polyculture, may be considered for follow-up research.
Staff: National Aquaculturist in collaboration with ALCOM Aquaculturist
Duration: 4 years.
Objective
To discuss the relevance of the findings of the pilot activities undertaken. To enable discussion and information exchange. To identify areas which need further investigation.
Protocols
PHASE I
Synthesis of results from socio-economic studies, monitoring data of small-scale farmers, simulation model and applied on-station research (activities 1,2,3 and 4 respectively). Preparation of results for the technical consultation.
PHASE II
Technical consultation for social scientists and aquaculturists involved and/or interested in investigations of intermittent harvesting strategies.
Staff: Phase I: ALCOM Socio-economist and Aquaculturist
Phase II: ALCOM Professional staff
Duration: Phase I: 4 weeks
Phase II: 1 week plus 1 week report writing
Objective
To introduce and test improved production and harvesting strategies and to monitor their impact on yields, income and protein availability.
Protocols
Detailed protocols for this activity will be developed once the results of Activities 1–5 are available.
Pilot project activities will be continuously documented. Details of the monitoring and evaluation procedures for each activity will be elaborated during the critical stages of pilot project implementation.
