Preliminary Study On Behavior Of Glyptosternum Maculatum Larvae And Juveniles

Glyptosternum maculatum is an important cold water fish in Tibet.It has high nutritional value and economic value.Because of its slow growth,late sexual maturity,artificial reproduction and domestication difficulties,Overfishing and the invasion of alien species have caused the poor resilience of the Glyptosternum maculatum magpie population,and its distribution area has rapidly shrunk,becoming a critically endangered species.This article uses fish behavioral research methods to preliminary study the early behavioral characteristics of the Glyptosternum maculatum juveniles,such as their preference for habitat water layer,hiding behavior,feeding rhythm and feeding behavior,light selection,and their growth and body characteristics under different photoperiod,and the influence of different photoperiods on its growth,body color and survival rate.In order to optimize the model of seedling cultivation and solve the bottleneck of seedling maintenance technology.1)Preference for water layer habitat.The Glyptosternum maculatum larvae and juveniles are mainly concentrated in the water layer 0 ～ 7 cm above the bottom,and a few branches are in the water layer 30-64 cm and190-195 cm.On the 3rd day,the Glyptosternum maculatum larvae and juveniles were mainly concentrated in the water layer 75 ～ 195 cm above the bottom.On the 4th to 11 th days,the Glyptosternum maculatum larvae and juveniles’ inhabiting water layer fluctuated greatly,and the water layer from 0 to 195 cm was distributed.On the 12 th to 16 th days,the depth distribution of the habitat water layer tended to be polarized.On the 17 th to 30 th days,the depth of the aquatic and juveniles’ inhabiting water layer was mainly distributed in the water layer below 5cm.In view of the characteristics of the habitat water layer,it is recommended that both floating and sinking feeds be placed at the same time when feeding.2)Hiding behavior.During the experiment,the preference of the Glyptosternum maculatum larvae and juveniles to the gap was significantly higher in daytime(7-20 points)than in night(21-6 points)(p < 0.05),at night(except for6,11-13 feeding days),there was no preference for gap(p > 0.05).The day has no preference behavior for the gap(p > 0.05),and at night(except for opening 6,11 ～ 13 days)has no preference behavior for the gap(p > 0.05).On the12 th,13th,15 th and 24 th feeding day,the larvae and juveniles showed a preference for small gaps(0.9 cm)(p < 0.05);On the 2nd and 3rd feeding day,the larvae and juveniles showed preference for bottom gaps(p<0.05);On the 5th,6th,8th,21 st and 24 th feeding day,the larvae and juveniles showed a preference for surface gaps(p<0.05);The preference of the whole day’s larvae and juveniles to the stone substrate was significantly higher than that of the sand substrate(p < 0.05).Under the light compensation of 400±50 xl,there was no obvious preference for the different background colors on larvae and juveniles;under the light compensation of 10±2 xl,the preference for the black bottom was significantly higher than that for the white bottom,the black bottom and the gray bottom,while the preference for the gray bottom and the white bottom was not significant(p > 0.05).3)Feeding rhythms and feeding behaviors.The Glyptosternum maculatum larvae and juveniles can feed at 0,6,12 and 18 o’clock,and there was no significant difference in feeding rate and satiety rate(p > 0.05).When a small and appropriate amount of micro-particulate feed and a small amount of cut mosquito larvae were fed at the center of the test aquarium,Glyptosternum maculatum larvae and juveniles did not ingest;The test fish showed very active feeding behavior when there was an excessive amount of chironomid larvae.In terms of the maximum response distance,feeding of Chironomid larvae was significantly larger than feeding of microparticulate feed(p <0.05).The feeding rate and satiety rate of fish fed with excessive amounts of micro-particulate feed,excessive chironomid larvae,and appropriate amount of micro-particulate feed were significantly higher than those of other test groups(p <0.05).The feeding time of excessive micro-granular feed,excessively cut mosquito larvae,and suitable micro-granular feed fish was significantly lower than that of other test groups(p <0.05).4)Preference of light intensity and influence of photoperiod on its growth performance.During the whole test period,the test fish before and after feeding were placed in the gradation zone,and the test fish moved upstream to the dark zone,and only remain in the dark zone.Glyptosternum maculatum larvae and juveniles have a significantly higher preference for dark areas than for light areas(P <0.01).Four weeks before the test,there was no significant difference in weekly average weight gain between different photoperiod test groups(p > 0.05).Under the experimental breeding conditions,the survival rate of the first three weeks reached about 90%,and there was no significant difference in survival rates between the groups(p> 0.05).On the 28 th day,the survival rate of the all-light group decreased significantly,which was significantly lower than that of the all-dark group and the natural photoperiod group(p <0.05),and there was no significant difference between the composition of the all-dark group and the natural photoperiod(p> 0.05).On the 35 th day of the experiment,the survival rate was significantly different between the groups(p <0.05).The survival rate was as follows: All dark group> Natural light cycle group>All light group.After the experiment,the body color of the juveniles in the full light group was the darkest,followed by the natural light period group,and the lightest in the dark group.The Glyptosternum maculatum plover has a very strong negative phototaxis,and the Glyptosternum maculatum plover can feed and has a high survival rate in the dark environment,so the dark environment should be maintained during the breeding process.