sponge fishing

Sponge-fishing, disease and farming in the Mediterranean Sea
Roberto Pronzato *
DIP.TE.RIS. (Dipartimento per lo studio del Territorio e delle sue Risorse), Università degli Studi di Genova, Via Balbi 5, 16126 Genova, Italy

*Correspondence to Roberto Pronzato, DIP.TE.RIS. (Dipartimento per lo studio del Territorio e delle sue Risorse), Università degli Studi di Genova, Via Balbi 5, 16126 Genova, Italy

Keywords
sponge; Mediterranean; organic waste; integrated mariculture system; eutrophication

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. Copyright © 1999 John Wiley & Sons, Ltd.
Received: 18 February 1998; Accepted: 24 June 199Commercial sponge fishing in Libya: Historical records, present status and perspectives
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M. Milanesea, b, Corresponding Author Contact Information, E-mail The Corresponding Author, A. Saràa, b, R. Manconic, A. Ben Abdallad and R. Pronzatoa

aDipartimento per lo Studio del Territorio e delle sue Risorse, Università di Genova, Corso Europa 26, 16132 Genova, Italy

bStudio Associato Gaia snc, Via Brigata Liguria 1/9, 16121 Genova, Italy

cDipartimento di Zoologia e Genetica Evoluzionistica, Università di Sassari, Via Muroni 25, 07100 Sassari, Italy

dFaculty of Science, Al-Fatah University, PO Box 606, Tripoli, Libya
Received 29 January 2007;
revised 30 August 2007;
accepted 14 September 2007.
Available online 22 September 2007.

Abstract

Natural bath sponges (genera Spongia and Hippospongia, Porifera, Demospongiae) have been harvested for millennia to be used as aids to beauty and body tools, in traditional and modern medicine as well as in painting. Recently, a series of severe epidemics have affected Mediterranean commercial sponges fostering the overexploitation of remaining fishing grounds. Furthermore, Mediterranean bath sponges attain the highest prices compared to Caribbean or Indo-Pacific ones but little or no correct information on origin is transferred to the final buyer. A complex network of re-selling activities and the lack of labelling make it almost impossible to track the pathway of sponge trade.

Some of the finest Mediterranean natural bath sponges come from Libya. Nevertheless, little information on Libyan sponge banks and trade have been available mostly given the former international ban. Under an Italian–Libyan joint-project it was possible to assess the past and present situation of sponge fishing in Libya, roughly covering a period of 150 years. After rather low production in years 1860–1879, average crop exceeded 40 t/year between 1880 and 1929. The peak was recorded in years 1920–1929 (almost 70 t/year on average). Today Libyan sponge fishery and trade are mostly confined to the eastern area of the country. Less than 10 t/year are currently harvested. According to a preliminary SCUBA diving survey along the Libyan coasts, sponges belonging to the order Dictyoceratida appear to be the most conspicuous sessile invertebrates in the investigated areas. Here, sponges belonging to the genera Ircinia and Sarcotragus (commonly defined “wild sponges” with no commercial value) appear to be more abundant than those belonging to the genera Spongia and Hippospongia. Sustainable approaches to the exploitation of this valuable natural resource such as sponge farming are proposed and discussed.

Keywords: Bath sponges; Spongia; Hippospongia; Libya; Harvest; Trad