�ݺ�ߣ

At present laboratory reagent companies are suspending supply of specialised agar products due to low availability of raw material. These bacteriological/technical agars used in laboratories around the world are predominantly obtained from species of a single red algal genus, Gelidium. Harvesting of natural populations is the only source of feedstock as cultivation has never been feasible. Here we analyse historical landings data since the 1920s in all countries where natural Gelidium resources have been harvested. Up to WWII Japan was the only source of agar but then other countries like Spain, Portugal, Morocco, Mexico, and South Africa began to survey and exploit local Gelidium resources. Gelidium landings peaked in the 1960’s, while Japan lost market dominance. A sustained decrease in landings to less than 50% of peak annual values has occurred since. This trend was accompanied by concentration of feedstock production in just one country, Morocco, which contributed over 70% of world supply in the last two decades. A sudden decline in this country’s landings will have a disproportionate effect on world availability of Gelidium. This is actually the present situation when landing and export quotas were recently implemented in Morocco in order to safeguard the natural resources. Thus Gelidium agar is now undersupplied and priced itself out of the food industry but the increasing demand of bacteriological and technical agars will probably create an opportunity for historical producers, where production has declined, to get back into the market. If an interest in Gelidium resource exploitation is renewed adequate scientific management practices should be implemented. For this, simple harvest statistics such as daily harvest yields and harvest effort need to be collected by harvest area. Estimates of both the standing stock and the exploitation rate of the resource can then be calculated, without the need for time and space extensive, high cost sampling assessments.Read less