Study On The Community Structure And Fishery Biological Characteristics Of Gobioidei In Laizhou Bay

In this paper,species composition,community structure,fishery and biological characteristics and the relationship between the abundance of Gobioidei and environmental factors were studied based on the fishery and biological data collected in beam trawl surveys conducted in May,August,October,December of 2011.And fish were captured at 20 sites of the study area(37°12'N—37°40'N,119°05'E—120°00'E).The results as follows(1)12 kinds of Gobioidei(Acanthogobius flavimanus,Acanthogobius ommaturus,Acanthogobius lactipes,Amblychaeturichthys hexanema,Chaeturichthys stigmatias,Ctenotrypauchen chinensis,Favonigobius gymnauchen,Acentrogobius pflaumii,Myersina filifer,Odontamblyopus lacepedii,Tridentiger barbatus,Tridentiger trigonocephalus)were captured in Laizhou Bay,which belonged to 9 genera.Of the Gobioidei in Laizhou Bay,10 kinds(Acanthogobius ommaturus,Acanthogobius lactipes,Amblychaeturichthys hexanema,Chaeturichthys stigmatias,Ctenotrypauchen chinensis,Favonigobius gymnauchen,Acentrogobius pflaumii,Odontamblyopus lacepedii,Tridentiger barbatus,Tridentiger trigonocephalus)were captured in spring,6 kinds(Acanthogobius ommaturus,Chaeturichthys stigmatias,Ctenotrypauchen chinensis,Acentrogobius pflaumii,Myersina filifer,Tridentiger barbatus)were captured in summer,7 kinds(Acanthogobius flavimanus,Acanthogobius ommaturus,Amblychaeturichthys hexanema,Chaeturichthys stigmatias,Acentrogobius pflaumii,Myersina filifer,Tridentiger barbatus)were captured in autumn and 7 kinds(Acanthogobius flavimanus,Acanthogobius ommaturus,Amblychaeturichthys hexanema,Chaeturichthys stigmatias,Odontamblyopus lacepedii,Tridentiger barbatus,Tridentiger trigonocephalus)were captured in winter.And we can see that Acanthogobius ommaturus,Chaeturichthys stigmatias and Tridentiger barbatus were captured in each season.Among these Gobioidei,the quantity of Chaeturichthys stigmatias and Acanthogobius ommaturus was more than others.The number of Chaeturichthys stigmatias was over 50,000 and the number of Acanthogobius ommaturus was over 10,000.Chaeturichthys stigmatias Acanthogobius ommaturus together account for 97.34%of the weight of Gobioidei.(2)Chaeturichthys stigmatias and Acanthogobius ommaturus were the dominant species of the survey in Laizhou Bay and Acanthogobius flavimanus was the important species.The dominant species and important species were different in each season.The number of dominant species and important species were more than other seasons.In spring,Acanthogobius ommaturus,Ctenotrypauchen chinensis,Chaeturichthys stigmatias and Acentrogobius pflaumii were dominant species and Acanthogobius lactipes,Odontamblyopus lacepedii and Amblychaeturichthys hexanema were important species.Chaeturichthys stigmatias and Acanthogobius ommaturus were the dominant species in summer and autumn.There was no important species in summer and Amblychaeturichthys hexanema was the important species in autumn.Acanthogobius ommaturus,Acanthogobius flavimanus,Chaeturichthys stigmatias were the dominant species and Tridentiger barbatus was the important species in winter.(3)We used CLUSTER to study the community structure of Gobioidei in Laizhou Bay.The result showed that the community structure of Gobioidei could be divided into 3 groups in the similarity of 66%with the stress level in 0.18 of MDS:the Tridentiger trigonocephalus group(Group One),the north Laizhou Bay group(Group Two),the west and south-central Laizhou Bay group(Group Three).Group One included stations SL11,SL16,SL18,Group Two included SL03,SL04,SL05,SL06,SL09,SL19,Group Three included SL01,SL02,SL07,SL08,SL10,SL12,SL13,SL14,SL15,SL17,SL20.ANOSIM showed that species compositions in the three groups were very significantly different(p<0.01),and with very significant between Group Three and Group One,Group Three and Group Two.SIMPER analysis showed that Chaeturichthys stigmatias and Acanthogobius ommaturus had a significant influence on each group.And Tridentiger trigonocephalus,Acanthogobius flavimanus,Amblychaeturichthys hexanema,Ctenotrypauchen chinensis,Acanthogobius lactipes had influence on every two group.(4)For Acanthogobius ommaturus,the standard length was 45-315mm,with a mean length of(131.29±44.17)mm.The dominant standard length was 65?190mm,accounting for 88.03%of the abundance.The body weight was 1.4?275.7g and the mean weight was(25.14±21.79)g.The dominant body weight was 2?48g,accounting for 88.95%of the abundance.For Chaeturichthys stigmatias,the standard length was 35?172mm,with a mean length of(86.01 ±19.55)mm.The dominant standard length was 60?115mm,accounting for 85.69%of the abundance.The body weight was 0.5?43.9g and the mean weight was(7.97±5.95)g.The dominant body weight was 2?14g,accounting for 83.05%of the abundance.(5)The length-weight relationship of Chaeturichthys stigmatias was W=1.33×10-5L2 94(n=2780,R2=0.951),and the length-weight relationship of Acanthogobius ommaturus was W=1.92×10-4L2 37(n=1687,R2=0.913).The b value of the length-weight relationship of Chaeturichthys stigmatias was 2.94,which closed to 3,we could treat Chaeturichthys stigmatias as a kind of constant growth fish approximately.And Acanthogobius ommaturus was a kind of allometric growth fish.Von Bertalanffy formula was used to estimate the growth of Chaeturichthys stigmatias.Von Bertalanffy growth parameters was estimated using the ELEFAN I program.Values found were k=0.66,L?=297,and to=-0.24.(6)The condition factor value of Acanthogobius ommaturus was lowest in spring and highest in summer of the whole year,the same as Chaeturichthys stigmatias.The trend of condition factor value for Acanthogobius ommaturus was decreasing from summer to winter gradually.The condition factor value of Chaeturichthys stigmatias in winter was higher than it in autumn.(7)The space distribution of Gobioidei was different by seasons.In spring,there was more Gobioidei in south central Laizhou Bay and the Yellow River estuary and its adjacent waters.In summer,most Gobioidei lived in south Laizhou Bay and the Yellow River estuary and its adjacent waters.In autumn,most Gobioidei lived in southwest Laizhou Bay.In winter,we caught more Gobioidei in the west coast of Laizhou Bay.(8)Generalized additive model(GAM)was used to analyze the relationship between Goboidei and environment factors and akaike information criterion(AIC)was used to find the optimal model.The model showed that the model including month X latitude,bottom temperature,dissolved oxygen,Chlorophyll,depth and transparency was the optimal model based on AIC and could explain 76.7%of the variance in biomass of Gobioidei.Monthxlatitude,bottom temperature and dissolved oxygen had very significant influence on the biomass of Gobioidei(P<0.01).Chlorophyll,depth and transparency had significant effect on the biomass of Gobioidei(P<0.05).And month X longitude,bottom salinity,PH and chemical oxygen demand(COD)has less effect on the biomass of Gobioidei(P>0.05).