Hundreds of passengers who use water vessels in Lake Victoria were on Wednesday stranded as the Kenya Maritime Authority (KMA) started a crack down to ensure adherence to standards.
The crackdown follows several fatal accidents in Kenya, Uganda and Tanzania and the realisation that many vessels are not up to standard.
It began in Mbita town is Suba North, Homa Bay County and will spread to parts in Siaya, Kisumu, Migori and Busia counties.
Travellers to Luanda Kotino, Imbo and Uyoma in Siaya watched helplessly as boat riders were taken to waiting police cars by maritime officers.
Some 40 passengers who had booked the MV Mbita III ferry from Mbita town to Luanda Kotineo is Siaya County got their fare back as the vessel was impounded for operating without a valid license.
The KMA's Branch Vessels Inspector Alexander Munga and Homa Bay County Commissioner Irungu Macharia launched the operation.
By noon, the authority had arrested 12 people including a ferry captain, boat owners, fishermen and passengers.
The authority is looking for offenders including those who operate water vessels without licences, lack life jackets and training, and those who are negligent or work while drunk.
Vessels that operate in the lake include ferries, water buses and speed boats.
Mr Munga said the exercise began in Homa Bay because it has the largest share of Lake Victoria.
"The exercise will be continuous," he said, noting all vessels should be inspected annually.
"Most of the vessels have not been inspected. We have also issued a warning to fishermen not to operate without licences from KMA and the fisheries department," he added.