第一作者Thushani Suleka Madhubhashini Elepathage 是唐丹玲研究员的博士研究生，来自斯里兰卡。

Abstract: 

Swordfish (Xiphias gladius) are a highly migratory keystone species, found in tropical and  temperate seas that are influenced by environmental parameters. In the Bay of Bengal, the Arabian  Sea, and the ocean region around Sri Lanka, the environment is gradually changing as a result of  climate change. In this study, we identified the preferable environmental conditions for swordfish  using satellite-derived environmental data and in-situ fish catch data. We modeled the relationships  between fish distribution and the environment changes using Boosted Regression Trees (BRT) and  Generalized Additive Model (GAM) methods. The monthly mean fishing effort is comparatively  high from October to March and the fish catch rates are high from September to November.  Chlorophyll-a concentration has a positive relationship with catch rates while sea surface  temperature (SST), sea salt surface mass concentration (SSS), and effort show negative relationships.  Approximately 0.3–0.4 mgm？3 of chlorophyll-a, 28–28.5 °C SST, and (3–5)10？8 kgm？3 of SSS were  significantly correlated with high swordfish catch rates. According to the optimum environmental  conditions identified using the above models, the suitable environmental spatial and temporal  distribution was mapped. The results show that the optimum conditions for swordfish are in the  eastern region of Sri Lanka, around Thailand and Myanmar, from June to August, and around  Bangladesh, Myanmar, Pakistan, the west coast of Sri Lanka, and the east coast of India during  September to November.

Modeled effect of (a) year, (b) month, (c) effort, (d) Chlorophyll-a, (e) SST, and (f) sea surface  salt (SSS) mass concentration on swordfish catch rates in the study region. The black solid line  indicates the fitted GAM function and the ash color area indicates 95% confidence intervals. The  relative density of data points is shown by the rug plot on the x-axis and the data are indicated by  black dots.

The pelagic habitat of swordfish according to the distribution of optimum environmental  conditions. (Habitats are demarcated in red; land masks are indicated with an ash color.).