文蛤动态能量收支模型构建、验证与应用

为评估文蛤生态容量，实验根据动态能量收支理论，基于R语言构建了文蛤动态能量收支模型，采用线性与非线性回归法估算模型参数，通过对比围塘环境下文蛤壳长、湿重、软体部湿重的实测值与模拟值验证模型，并应用于模拟黄海海域滩涂区文蛤的生长过程。结果显示，文蛤模型主要参数形状系数、阿伦纽斯温度系数和单位体积结构物质所需能量分别为0.57、9 278 K和2 056 J/cm³；实测与模拟的文蛤壳长、湿重和软体部湿重相关系数R²平均为0.996，模拟值与实测值的平均误差为3.58%；如东沿海区域6月实测文蛤软体部干重为0.48 g，壳长3.12 cm，模型模拟的软体部干重、湿重和壳长分别为0.476 g,6.6 g和3.2 cm。研究表明，实验构建的文蛤动态能量收支模型的准确度较高，可真实地反映出文蛤在自然水域中的生长过程，为评估文蛤生态容纳量及构建文蛤相关的生态系统模型提供科学参考。

Construction, validation and application of dynamic energy budget model for benthic bivalve clam (Meretrix meretrix)

Benthic bivalve clam (Meretrix meretrix) is one of the most important economic shellfish and widely distributed in the coastal tidal flats of China. The coastal areas of Jiangsu and Liaoning Provinces are natural nursing ground for clams, and the amount of clams had reached more than ten thousand tons in the history. However, due to overfishing, the fishery resources of clams generally decline. Understanding the growth process of M. meretrix in natural waters is of great theoretical significance and application value for the quantitative research on assessing the ecological capacity of M. meretrix. Because the matter circulation and the energy flow are complex in marine ecosystems, it is difficult to evaluate the dynamic growth changes of benthic bivalve clam in natural waters through experiments. A mathematical model, as a research tool, provides an effective tool for the study of shellfish growth in varied water environments. In this study, a new model of the clam, based on the dynamic energy budget theory, was constructed. The developed model was parameterized based on the physiological and ecological data of clam obtained in laboratory and field experiments, which were analyzed by linear and nonlinear regression methods. The relationship between shell length and wet weight of clam was verified based on the comparison between data observation and simulation. The change process of shell length and wet weight of soft tissue was simulated by using WHDEBSTD software, which was originally developed by the authors, in the field environment. The results show that the shape coefficient of the clam is 0.57, the Arrhenius temperature value is estimated to be 9278 K, and the volume-specific cost for structure value is 2056.3 J/cm³. The good agreement between measured and simulated results of shell length, total weight and soft body weight change can be found in earth pond culture of M. meretrix. The average correlation coefficient R² is about 0.996 and the average discrepancy between simulated and measured is 3.58%. In the coastal area of Rudong, the shell length and the soft body dry weight of M. meretrix were observed as 3.12 cm and 0.48 g in June, and the simulated value were 3.2 cm and 0.476 g, respectively, which indicate that the numerical model could reproduce the growth of M. meretrix in the natural sea. This study provides useful information for research on constructing the clam module in ecosystem model and evaluating the ecological capacity of clam in natural waters. However, some discrepancies can still be found between the simulated and the observed growth of clam, which might be caused by the difference between the sexes of the clam in terms of growth and the fact that the hibernation state of M. meretrix cannot be reproduced by the numerical model. Follow-up studies will focus on the sexual differences and the hibernation state of clams, so as to further improve the accuracy and stability of the model.