Study On The Spatiotemporal Characteristics Of Water Environmental Factors In Xiamen Sea And Their Relationship With The Community Structure Of Fishery Resources

In this paper,Pearson correlation analysis,inverse distance weight method,canonical correlation analysis and other methods were used to analyze the water quality characteristics of Xiamen sea from 2011 to 2018,as well as the dominant species,relative resource density and community structure diversity of fishery resources from 2013 to 2014;Finally,Pearson correlation analysis and CCA canonical correlation analysis were used to explore the correlation between water quality factors and fishery resource structure from the perspective of single factor and system.（1）From 2011 to 2018,the interannual changes of DO,pH,salinity,and water temperature were relatively stable;COD remains relatively stable within the concentration range of 0-2mg/L;Nutrient indicators（DIN,DIP,silicate）fluctuated between 2011 and 2015,with a significant downward trend from 2016 to 2018;The interannual variation of chlorophyll a is significant;The petroleum industry remained at a stable low level from 2011 to 2015,but showed an upward trend from 2016 to2018;The Spearman rank correlation analysis results indicate that the annual average values of each indicator do not show a significant interannual change trend,and only DIN’s interannual change data in October showed a significant negative correlation（rs=-0.929）.ANOVA one-way ANOVA analysis showed significant seasonal differences in water temperature,DO,and petroleum.The seasonal changes in nutrient indicators and other pollutant indicators were not significant.The results of Spatial analysis of water quality factors show that DIN and DIP are two important pollution factors,which have seriously exceeded the standard in different years;The western sea area is the area with the most severe pollution,with salinity,pH,and DO showing low in the west and high in the east,and pollutants and nutrients showing spatiotemporal characteristics of high in the west and low in the east.（2）The relative density of fishery resources at 24 survey stations in Xiamen from 2013 to 2014 showed seasonal characteristics of autumn>summer>winter>spring,and the fishery resources showed a trend of degradation;The results of dominance analysis indicate that there are a total of 15 dominant species in the surveyed sea area throughout the four seasons,among which the Chinese croaker is the dominant species throughout the four seasons;The diversity index H,shows the characteristics of autumn=summer>spring>winter,which is low in the west and high in the east in autumn and summer;The richness index D has the characteristics of autumn>summer>spring>winter among different seasons;The uniformity index J,does not differ significantly among different seasons.（3）Pearson correlation analysis of water quality factors and fishery resource community structure showed that there was a close relationship between nutrient indicators（DIN,DIP and silicate）and other water quality indicators;The evenness index J,was significantly negatively correlated with silicate（p<0.05）,the relative resource density was significantly correlated with pH and chlorophyll a（p<0.05）,and the richness index D,diversity index H,,and number of species were not significantly correlated with water quality factors.The results of typical correlation analysis indicate that this study can extract a pair of typical variables with strong correlation（r=0.990）.The variables representing water quality and fishery resource community structure are silicate and evenness index,respectively;The typical variable V₁has a negative correlation with silicate,but the explanatory power of the typical variables U₁and V₁to their respective and each other’s variance is at a low level;Comparing the two correlation analysis methods,the systematic analysis method is more scientific and practical in exploring the correlation between fishery resource group structure and influencing factors.