Abstract:
Light adaptation process of Russel`s scad (Decapterus ruselli) by natural condition and different light illumination were examined in respects of the application of light fishing operation. The experiment were conducted in Makassar Strait used a bagan rambo (large typed liftnet with light attraction) with ligting power 16.4 kW. From the total 33 individuals Russel`s scad (TL: 8.3 – 20.5 cm), their eye’s balls were sampled and prepared for the histological examination of the retina. Adaptation ratio was calculated from the cone and pigment movement in each experimental condition by using Cone Index and Pigment Index.
Concerning the light adaptation process, the movement patterns of the pigment and cone were different in natural condition and simulation, where in the natural condition the Russell` scad caught by the bagan rambo is light adapted occurred after midnight. The other hand in the simulation condition Russel`s scad was light adapted in 45 and 35 lux after 1 hour lighting. Russell` scad very sensitive to the light, as shown by the accurence of cone movement even the light illumination was low of 14 lux.
In relation to the fishing operation of bagan rambo, if the Russell`s scad as a target species, the effectively hauling time can be done as 3 times at the one night time is enough.
