IASUS sea trials refine sponge cultivation methods in Cyprus

Sea trials conducted since August 2025 have helped IASUS refine how marine sponges are handled and secured on underwater cultivation structures in Cyprus. The latest deployment, using revised handling procedures and cultivation designs, recorded the project’s best survival and growth so far and provides a stronger basis for future work alongside marine fish farms.

IASUS (Increasing Aquaculture Sustainability Using Sponges) is examining whether sponges can be incorporated into integrated multi-trophic aquaculture (IMTA) systems with European seabass and gilthead seabream. In IMTA, species from different trophic levels are cultivated together so that nutrients or organic material from one part of the system can be used by another. Sponges are of interest because they naturally filter particles and dissolved material from seawater and can also provide material for further research.

The sea trials began in August 2025. Early deployments exposed several practical obstacles: survival was low in some groups, cultivation structures had to be replaced, and heavy biofouling made maintenance and monitoring more difficult. Lantern nets also accumulated unwanted growth and did not secure each sponge well enough. The tests showed that different local sponge species did not respond equally to the cultivation conditions.

The team responded by revising both the handling protocol and the cultivation design. Sponge fragments were removed with cleaner cuts, transported rapidly in cool, well-oxygenated seawater and kept out of the air as little as possible. In May 2026, the team installed new structures in different positions and tested improved ways of securing each sponge. The final group produced the best survival and growth recorded during the project to date. These results suggest that much of the early loss was associated with handling stress and unsuitable structures, rather than an inability of the sponges to grow under farm conditions.

One of the most practical designs was a system of individual PVC mesh bags attached separately to a larger underwater structure. Each sponge can be installed, inspected and maintained individually, while the system can be expanded gradually. This is an encouraging operational result, but it should not yet be interpreted as proof of commercial-scale sponge farming or confirmed biofiltration performance.

As IASUS enters its final phase, the team will use these findings to guide future sponge cultivation and examine how sponges could be grown alongside fish farms within an IMTA approach. The project continues until 31 October 2026.

IASUS is implemented by Marine & Environmental Research (MER) Lab Ltd. in collaboration with SeaWave Fisheries Ltd. and the National and Kapodistrian University of Athens. It is co-financed by the Republic of Cyprus and the European Regional Development Fund through the Operational Programme Thalia 2021–2027 and the Research and Innovation Foundation.