Study On Behavior Of Yellow Catfish Larvae,Pelteobagrus Fulvidraco

The yellow catfish, Pelteobagrus fulvidraco, is one of the most important freshwater fish in China. People love this species of fish because of its tender flesh, delicious flavor, and high nutrition value. Increasing demand for this fish has resulted in the development and intensification of aquaculture operations; however, there are few hatcheries throughout China providing larvae for pond stocking. In order to realize the biological characteristics and enhance the success of larval rearing, we need to know the early behavior of yellow catfish thoroughly. This study used the perspective of Behavior Ecology to understand the preference of early larvae of yellow catfish for swimming height, illumination, hiding and substrate. This information is expected to provide fundamental knowledge for larval rearing management of this fish species. The results are as follows:1 Swimming height above the bottomIn the swimming tube, days 3-10 larvae swam on or within 40 cm of the bottom. Days11-20 larvae swam a mean of 0-195 cm above the bottom; but days11-12 larvae mainly swam 0-20cm above the bottom, days 16-20 juveniles swam 40-60cm above the bottom. Days 21-32 juveniles still swam a mean of 10 cm above the bottom.2 Illumination choiceBefore ingestion, days 3-6 larvae significantly preferred bright illumination, but preferences were not significant for days 7,8 and 10 larvae. Day-11 larvae did not significantly prefer far away from illumination, but day-12 larva had no preference for illumination. Days 13-23 larvae spent most of the time in no illuminated habitat, and preference for no illumination was significant on days 13-23. Day-25 spent all of the testing time in no illuminated habitat. After ingestion. day 3 larvae significantly preferred bright illumination; days 4-8 larvae preferred bright illumination, but not significantly; days 10-23 larvae significantly preference for no illumination; and day 25 late larva significantly preference for no illumination.3 Cover choiceDays 1～18 larvae preferred hiding in gaps, but days 19～25 juveniles did not select gaps. Days 1～18 larvae preferred hiding in gaps during the day significantly (p< 0.05), compared with hiding in gaps at night. Days 2-7 larvae preferred hiding in 0.5 cm gaps significantly (p<0.05), compared with hiding in 0.3 cm gaps; days 9-18 larvae only selected a wide (0.5 cm) gap. Before days 18, larvae preferring the bottom of the gap (20 cm above the bottom) was significantly higher than the percentage of larvae in surface gaps (20 cm below the surface) during the day (p<0.05). Days 13～18 larvae preferring the bottom of the gap (20 cm above the bottom) was not significant at night (p>0.05), compared with the percentage of larvae in surface gaps (20 cm below the surface).4 SubstrateLater larvae from day 12 to day 18 preferred soil compared to fine sand, and preference was significant (p<0.05).Depending on the result above, the surviving rate of yellow catfish got 65% after larval rearing method improving, but the surviving rate was 30% before method improving.