Sampling procedures
The respondents were sampled using proportionate to boater-population size sampling techniques to obtain the required number of boaters per cluster. Study participants were identified from their shelters at the landing sites. The sampling frame was obtained from the landing site management committee. At each shelter, simple random sampling was used to select the boaters for interview. At each landing site, the interviews started at about 7:30 am (the time many boaters return from the lake) to 4:30 pm (the time they start to go back to the lake). Diligence was taken to ensure that no participant (boater) was interviewed more than once.