Characteristics of submarine water temperature distribution of Trichiurus haumela in the East China Sea and Southern Yellow Sea with the improvement of the analysis methods

The study of the relationship between fishery organisms and water temperature is an important part of fishery scientific research, and the analysis of the suitable water temperature range of fish is an important aspect of this content. In this study, based on the distribution data of Trichiurus haumela resources obtained from a large-scale survey in four quarters from 2014 to 2015, the water temperature range analysis method was improved on the basis of previous studies to avoid some subjective factors in the analysis. A new biological subject temperature range analysis method was created and compared with the traditional frequency method and the previous biological subject method. The results show that the proportion of sites covered by the frequency method is relatively good, but the biomass coverage rate is relatively poor; in the previous biological main body method, the cumulative biomass coverage rate was the highest, and the site coverage rate was also relatively good. The disadvantage is that there are many subjective factors added in the operation process, and the distribution range is discontinuous and contains individual narrow range. In the new method, because its temperature range is relatively concentrated and short, the coverage of the site and biomass is not very high, but the biomass density in the determined temperature range is the highest, and the minimum range which can accommodate the most biomass is found and the distribution range is continuously concentrated. The characteristics of the biological spatial distribution will directly affect the results of the temperature range analysis method, for example, the aggregation degree of the spatial distribution of the belt fish is obviously lower than that of Larimichthys polyactis, that is, the spatial distribution of the belt fish is relatively uniform. As a result, one of the branches of the frequency distribution is consistent with its biological main body distribution, while the small yellow croaker has no such results, and there is a great difference between its frequency distribution and biomass distribution. The analysis also found that the populations with higher biomass are generally distributed in the waters with higher water temperature, which may be related to the good nutritional status of the population and the demand for rapid growth. The uneven distribution and aggregation in biological space may be related to the food needs and predation characteristics of species. According to the temporal and spatial distribution characteristics of the high biomass population of T. haumela, it is analyzed and inferred that the population may correspond to the reproductive fish schools of spring and summer and autumn.