Commercial sponge fishing in Libya: Historical records, present status and perspectives

摘要

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 modem 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. (c) 2007 Elsevier B.V. All rights reserved.