Spatiotemporal heterogeneity of Priacanthus spp. resources in the northern South China Sea

It’s helpful to know the formation of fishing grounds by the center of gravity of fish resource density and temporal and spatial heterogeneity. The traditional economic fish resources are declining owing to the impact of overfishing, environmental change and other factors. Priacanthus spp., the main catches in bottom trawls in the South China Sea, are important ecologically. But few studies on their spatial-temporal patterns of distribution are available, and spatial autocorrelation of data is also scarce in the studies. Analysis of temporal and spatial heterogeneity on the distribution of Priacanthus spp. in the northern South China Sea has been essential for sustainable development and rational management of the fishery. To investigate temporal and spatial distribution of Priacanthus spp. resource density, we used the data of bottom trawl fishery in the northern South China Sea by a fishery information network from 2009 to 2014, for spatial analysis of center of gravity and semivariogram plots to investigate temporal and spatial distribution of Priacanthus spp. resource density. The results showed that the resource density of Priacanthus spp. decreased gradually and the differences were extremely significant (P<0.01) from 2009 to 2014. The maximum value of resource density was (26.69±7.34) g/h/kW/nets in 2012. The center of gravity of the resource density which was distributed between the 50-m and 100-m isobath in the middle part of the survey area, had no significant difference (P>0.05). The spatial distribution of Priacanthus spp. showed a well-organized structure, with strong spatial autocorrelation in 70–90 km. Spatial heterogeneity in resource density of Priacanthus spp. appeared to be caused less by randomness than by structural variations. The spatial distribution of Priacanthus spp. showed weak spatial autocorrelation when the distance exceeded 90 km.