PARENT SESSION
Poster Session # 7: Restoration, Resource Management, and Conservation.

Monday, August 4 Presentation from 5:00 PM to 6:30 PM. SITCC Exhibit Hall B.

Monitoring the ecosystem condition of the shallow sea by using the sound of snapping shrimp.

Watanabe, Moriyoshi^*,1, Sekine, Masahiko¹, UKITA, Masao¹, IMAI, Tsuyoshi¹, ¹ Yamaguchi University, Ube, Yamaguchi, JAPAN

ABSTRACT- Although detecting the impacts of pollution on sea ecosystem is very important, measuring the condition of living organisms in the sea requires some skill and patience. Snapping shrimp (Genus Alpheus), which are bottom-living animals, are distributed all over the world coastal area and yet have not suffered from fishing pressure. The rapid closure of the chela emits a powerful pulse sound accompanied by water jet. An idea came out: doesn't this sound represent the number of snapping shrimps (and hopefully the ecosystem condition, too) on the bottom of the sea? The objective of this research is to establish a monitoring method of the ecosystem condition in the shallow sea by monitoring the snapping shrimps sound. The pulse count (the number of snap per minute) measuring method is quite simple. The pulse count can be achieved merely by recording their sounds for a few minutes without special biological knowledge by using a hydrophone and a PC with the software we developed. From field surveys conducted since 1996, the following findings have been obtained; (1) A few minutes' measurement of pulse count is sufficient to acquire the pulse count value that represents the study period. (2) The pulse count changes according to water temperature under the normal condition. The shrimp population can be estimated from the pulse count and the water temperature. (3) The pulse count seems to decrease in the place where the water quality is not very good, like the head of Tokyo Bay or the Bosporus. (4) The pulse count sharply falls by the occurrence of hypoxia and red tide. This method has shown premise to be a new, simple and effective technique of monitoring the ecosystem health in coastal areas.

Key words: monitoring, Genus Alpheus, pulse sound, pollution