Sponge‐fishing, disease and farming in the Mediterranean Sea

Abstract

1. Some Mediterranean sponge species belonging to the genera Spongia and Hippospongia, have been harvested for commercial purposes since ancient times. Recently, a widespread epidemic has greatly reduced the density of sponge populations which has had serious repercussions in the commercial field.2. The synergetic action of harvesting and disease has taken a number of populations to the brink of extinction. Sponge-population densities are steadily decreasing and their recovery after the disease event is incomplete and has taken a long time.3. There is a simple solution to the problem: sponge-farming. Trials have been underway since the beginning of the century and recently, Cuba, the Philippines and Micronesia Islands have started commercial sponge-farming. 4. Sponges are naturally able to remove dissolved organic matter, organic particles and bacteria from the water-column and this ability could be exploited in an integrated mariculture system. Floating cages for fish production result in the release of a lot of organic wastes that can be used as a source of food for surrounding intensive commercial sponge communities. Such an integrated system could result in effective eutrophication control, commercial sponge production and a consequent reduction of fishing effort on already heavily-stressed natural sponge populations.

Sponge Mass Mortalities in a Warming Mediterranean Sea: Are Cyanobacteria-Harboring Species Worse Off?

“…It has been reported that when a small proportion of the sponges are affected, populations are able to recover [8]. In contrast, when mortality rates are high (similar to the values reported here) or if other mortality sources are acting synergistically (e.g., overfishing), sponge populations may disappear [39]. As a result, we may predict a dramatic extinction of the populations studied.…”

Morphotypes ofSpongia officinalis(Demospongiae, Dictyoceratida) in two Mediterranean populations

“…In the long term, the most evident phenomena were mainly fragmentation and re-organisation of the sponge body (Fig. 6A) in accordance with the clonal strategies of sponges and their phenotypic plasticity (Wulff, 1985(Wulff, , 1991Pronzato & Pansini, 1994;. A wide temporal variability in body shape and size due to fragmentation into clonal strains and subsequent regenera- tive processes and re-aggregation phenomena characterise Mediterranean populations of other species such as Oscarella lobularis, Cacospongia mollior, Anchinoe tenacior, Clathrina clathrus, Chondrosia reniformis and Chondrilla nucula (Pansini & Pronzato, 1990;Pronzato & Pansini, 1994;Gaino et al, 1995).…”

Growth and survival of marine sponges, Stylissa massa (Carter, 1887) and Liosina paradoxa (Thiele, 1899) in sea and land based culture systems

“…In our study, mortality occurred during first 15 days and hardly any mortality was noticed further as mostly sponges were acclimatised. Similar observations showed that morality mostly occurs in the initial days of transplantation (Pronzato et al, 1999;van Treeck, 2003) and hence survival rates will give good impression on the sensitivity of the species (Devoogd, 2005).…”