| Saury(Cololabis saira)fishery in the Northwestern Pacific high seas is an important fishing ground for Chinese distant-water fishery.Duo to the convenient location and abundant resources, it has developed rapidly in recent years, with number of fishing fleets and catches substantially increased. To strengthen the study on the saury resource and fishing ground in the Northwest Pacific Ocean is essential for the further development of Chinese saury fishery.The fishing ground of saury fishery in the Northwest Pacific Oceans it in the outside of the 200 nautical mile exclusive economic zone(EEZ)of Russia and Japan. Specifically, the longitude and latitude scope are 44-55 ° N, 152- 164 ° E. Study the temporal and spatial variations of Cololabis saira resources can provide a basis for the reasonable development of saury fishery in the Northwest Pacific Ocean.In this paper, firstly, we standardized the nominal CPUE(Catch Per Unit of effort) using generalized linear model(GLM) and generalized additive model(GAM). We further analyzed the spatial and temporal variations of the abundance of Cololabis saira using standardized CPUE. Then, we investigated the relationships between the abundance of C. saira and sea surface temperature(SST), chlorophyll(chl-a) in the spawning and feeding grounds using cross-correlation function. Finally, using linear regression model, we predicted the abundance of C. saira based on SST and chl-a, and verified the effect of the model using the data in the year 2015. The results were as follows:(1)There sults of standardized CPUE of saury fishery in the Northwest Pacific high sea. The effects of captain, year, month, longitude, SST, and interaction terms including year and longitude, month and longitude, latitude and longitude on CPUE is significant. GAM model account for 43.2% of the variance of CPUE, the results of CPUE standardization were good.(2)The interannual variation of the abundance of C. saira in the Northwest Pacific high seas. The abundance of C. saira showed first decreased and then increased phenomenon periodicallyfrom2003 to 2014,and there were two loops during this period. The abundance of C. saira showed decreasing trend during the period 2003-2003, but gradually increased from 2008 to 2011, then it continued declining in 2013, and increased to the highest level in 2014.(3)Spatial distribution of the abundance of C. saira in the Northwest Pacific high seas. The changes of barycenter of fishing ground over year were as follows: It moved to the northeast in 2003-2005 and 2009-2011, the abnormal environment resulted in the barycenter of fishing ground moving to the southwest in 2008, and the barycenter of fishing ground stabilized at154 °E,N 43 °in 2013-2014. The changes of barycenter of fishing ground over month were as follows: It moved to the northwest in May to August, and directed to Southwest in August to December. Furthermore, the barycenter of fishing ground moved to the northeast with the increase of Nino 3.4 SSTA, and it skewed slightly to the Southeast with the increase of SST and Chl-a.(4)SSTA in the area of Nino3.4 would have negative effect on spawning and feeding grounds SST after 3 months and 6 months, and it had positive effect on spawning and feeding ground SST after2 months and 12 months. Resource abundance had negative correlation with SST in the spawning ground, and had positive correlation with SST in the feeding ground. In addition, resource abundance also had positive relationship with SST in the spawning and feeding ground.(5)Resource abundance forecasting model. The resource abundance forecasting model that based on SST is better than the model that based on chl-a. In addition, the forecasting model that based on SST was a good predictor of significantly decreased abundance in 2015, and equation of the model was:CPUR=375.004-15.645*SST in spawning ground-1.337*SST in the feeding ground... |
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