基于最大熵模型模拟西印度洋剑鱼栖息地的时空分布

Simulation of spatio-temporal distribution of swordfish habitat in the western Indian Ocean based on maximum entropy model

剑鱼(Xiphias gladius)是一种高度洄游性鱼类,其迁徙和栖息地利用受海洋环境影响明显,理解其空间分布格局形成的机制对于资源的养护和管理具有重要意义。本研究利用2017−2019年中国印度洋延绳钓渔业观察员数据中剑鱼的渔获物信息作为物种出现数据,结合西印度洋海域的海表温度、海面高度、叶绿素a浓度、混合层深度、海表盐度等环境数据,采用最大熵模型对剑鱼的栖息地适宜性分布进行了模拟。结果表明:(1)模型对印度洋西部剑鱼栖息地适宜性分布的模拟精度非常高,各个季节受试者工作特征曲线的曲线下面积都大于0.9,可用于模拟剑鱼潜在的栖息地适宜性分布;(2)研究区域内剑鱼适宜栖息地分布变化与实际作业位置变动基本一致,干季和湿季剑鱼栖息地高适宜性的区域分布都较为集中,但湿季分布范围要大于干季;(3)海表温度、海表盐度和混合层深度是影响西印度洋剑鱼栖息地适宜性分布的重要环境因子,在干季和湿季的最适范围分别为25.8~31.6℃、34.4~35.9、0.1~24.9 m和25.6~30.5℃、34.8~36.4、13.1~54.1 m。研究结果可为西印度洋海域剑鱼种群的可持续利用和科学管理提供必要参考信息。

Swordfish(Xiphias gladius)is a highly migratory fish whose habitat suitability is significantly influenced by the marine environment,and the prediction of its habitat using changes in the marine environment is of great scientific importance.In this study,we used the catch information of swordfish in the Chinese Indian Ocean Longline Fisheries Observer Data from 2017 to 2019 as species occurrence data,combined with the environmental data in the western Indian Ocean waters,including sea surface temperature(SST),sea surface height(SSH),chlorophyll a(Chl a)concentration,mixed layer depth(MLD),and sea surface salinity(SSS),the habitat suitability distribution of swordfish in the western Indian Ocean is simulated by using a maximum entropy model(MaxEnt).Model results show that:(1)the model has very high accuracy in simulating the habitat suitability distribution of swordfish in the western Indian Ocean,with AUC values greater than 0.9 in all seasons,and can be used to simulate the potential habitat suitability distribution of swordfish;(2)changes in the distribution of suitable habitat for swordfish in the study area are generally consistent with changes in the actual operational location,and the distribution of areas with high habitat suitability for swordfish is more concentrated in both the dry and rainy seasons,but the distribution range is greater in the wet season than in the dry season;(3)SST,SSS and MLD are important environmental factors affecting the habitat suitability distribution of swordfish in the western Indian Ocean.The optimum ranges of SST,SSS and MLD in the dry and rainy seasons are 25.8−31.6°C,34.4−35.9 and 0.1−24.9 m,and 25.6−30.5°C,34.8−36.4 and 13.1−54.1 m,respectively.The results of the study provide essential reference information for the sustainable use and scientific management of swordfish populations in the western Indian Ocean.