**Mert Gökalp 1,2,\*, Tim Wijgerde 2, Antonio Sarà 3, Jasper M. de Goeij 1,4 and Ronald Osinga 1,2**


Received: 29 November 2018; Accepted: 27 December 2018; Published: 5 January 2019

**Abstract:** In this study, novel methods were tested to culture the collagen-rich sponge *Chondrosia reniformis* Nardo, 1847 (Demospongiae, Chondrosiida, Chondrosiidae) in the proximity of floating fish cages. In a trial series, survival and growth of cultured explants were monitored near a polluted fish farm and a pristine control site. Attachment methods, plate materials, and plate orientation were compared. In a first trial, chicken wire-covered polyvinyl chloride (PVC) was found to be the most suitable substrate for *C. reniformis* (100% survival). During a second trial, survival on chicken wire-covered PVC, after six months, was 79% and 63% for polluted and pristine environments, respectively. Net growth was obtained only on culture plates that were oriented away from direct sunlight (39% increase in six months), whereas sponges decreased in size when sun-exposed. Chicken wire caused pressure on explants and it resulted in unwanted epibiont growth and was therefore considered to be unsuitable for long-term culture. In a final trial, sponges were glued to PVC plates and cultured for 13 months oriented away from direct sunlight. Both survival and growth were higher at the polluted site (86% survival and 170% growth) than at the pristine site (39% survival and 79% growth). These results represent a first successful step towards production of sponge collagen in integrated aquacultures.

**Keywords:** mariculture; sponge; *Chondrosia reniformis*; fishfarm; integrated multitrophic aquaculture
