Photo credit: Marx Perfecto C. Garcia (Philippines) Description: Abdel Rahman El Gamal (Founder of the website)
The inserted picture was taken in an aquaculture facility in China and shows several sizes of bamboo graders.
The use of bamboos in aquaculture goes back to about a century when bamboo cages were used in Indonesia. In countries where bamboos are abundant, bamboos have been introduced more in aquaculture as an eco-friendly material with lower cost and easier maintenance. Fish graders have been added to the use of bamboos.
Bamboo graders are commercially produced at the moment. As the case with other bar graders, the thickness of bamboo stems as well as the distance between them would determine the size of fish retained above the grader and those that passes through for a given species. That is why; graders are numbered according to the space between bars for easier use. It may need mentioning that freshly cut green bamboo are often flexible and can be shaped and manipulated for various uses including graders. Other treatments may be applied for the same purpose including the use of heat.