Abstract
SAIGUSA, MASAYUKI (Department of Natural Sciences, College of Liberal Arts and Sciences, Okayama University). 1987. An equipment to monitor the larval release activity in marine invertebrates. Benthos Research (Bull, Jap. Assoc. Benthology), 31 : 47-51.
A simple equipment monitoring the larval and/or gametes release of marine invertebrates in undisturbed condition is described. The activity recording device is based on the principle of detecting changes in transmitting infrared beam in water medium associated the release of larvae or gametes by photo-electric sensor. The recording system consists of a sensor unit (infrared source and receptor : OPE-S100 or E3S-2E4, Omron Co. Ltd.) and a photoelectric-switch unit with amplifier or controller (OPE-VA or S3S-A10, Omron Co. Ltd.).
Ovigerous female animal carrying well developed eggs is kept in a plastic cylindrical case with many pores, and the case is hanging in the glass beaker filled with artificial sea water. Infrared light beam source-receptor unit is set opposite sides of the beaker near the bottom. When larval disperse into the medium in the beaker, and the beam intensity passing through the medium decreases. This triggers a photoelectric switch which is placed outside of the experimental chamber, and the output of the system is monitored by the event recorder (R17-H12T, Fuji Electric Co.Ltd.). For example, experimental set up and results of monitoring of the case of a terrestrial crab, Sesarma haematocheir, are demonstrated.
