The development of an appropriate cultivation method was started concurrently with the evaluation of suitable species and in close collaboration with the first sponge farmers. In this phase many technicalities had to be clarified and a simple yet robust cultivation system that can easily be multiplied was developed. Some of the details that needed to be worked-out were:
- The minimum water depth at which sponges thrive and at which sponge farmers can spend as much time as possible without being required to swim.
- The optimal spacing between sponges.
- Sourcing rope material suitable for the construction of the farm and attachment of cuttings that is durable, cheap, easy to handle and locally available.
- The ideal cutting size, shape and suspension method.
- The minimum number of cuttings per farm necessary for two sponge farmers to make a living and to ensure that propagation does not require collection of additional sponges from the wild.
- The frequency at which cuttings need to be cleaned and trimmed.
- The right moment to harvest sponges.
- Methods to process, clean, preserve and dry sponges as well as appropriate packaging and labelling of the product.
- A training curriculum for sponge farmers and the outline of technical assistance needed for future support independent sponge farmers.
Sufficient staff time, funds, patience and active communication were the most important factors that helped us establishing the first sponge farms.
Experiences gained over a two-year period are not guaranteed to be applicable as such in future years as climate, water temperature etc. are subject to change. In that respect aquaculture is like land based agriculture where years of experience, and trial and error are key to shape best practices. The possibility of variability should be kept at the back of one’s mind when setting-up similar projects and needs to feed back in the form of a continuous supervision of the farmers with a focus on quality assurance and advancement of the methods applied.