Impact of Climate Change on Wintering Ground of Japanese Anchovy (Engraulis japonicus) Using Marine Geospatial Statistics

Shuhao Liu,Haiqing Yu,Jianchao Li,Zhenjiang Ye,Yongjun Tian,Yang Liu,Irene D Alabia,Jiahua Cheng

doi:10.3389/fmars.2020.00604

Abstract

Distribution and fluctuations in abundance of small pelagic species such as anchovy are largely affected by climate change. We hypothesized that the future projected rise in temperature will result to a northward shift of Japanese anchovy (Engraulis japonicus) habitat and a subsequent increase in relative abundance. To test this hypothesis, we explored the link between the Japanese anchovy abundance and environmental conditions using machine–learning and statistical models. The models were fitted with catch per unit effort (CPUE) as the response variable and remotely sensed data of sea surface temperature (SST), sea surface chlorophyll-a, assimilated information of sea surface salinity, meridional and zonal ocean currents, and depth as environmental covariates. Our results showed that the abundance of E. japonicus was significantly influenced by environmental factors. In particular, salinity front and SST highlight strong relationships with winter CPUE distribution. Based on these models, The results reinforced our hypothesis and showed that warming ocean will drive a substantial shift in Japanese anchovy habitat in the China Seas. SST and CPUE showed negative correlations with the El Niño Southern Oscillation index. These findings underpin ramifications of climate-driven habitat shift of small pelagic fish species on the regional marine ecosystem in the China seas.

Highlights

Climate change is considered as one of the major drivers of the fluctuations in abundance and distributions of small pelagic fish resources such as anchovy (Lecomte et al, 2004)
A histogram of residuals and normal quantile-quantile plots indicated that the distribution of residuals of generalized additive models (GAM) adequately conformed to the application of Gaussian distribution (Supplementary Material 2.2)
A comparison of the three models showed that GAM is the most suitable prediction model for wintering Japanese anchovy

Summary

Introduction

Climate change is considered as one of the major drivers of the fluctuations in abundance and distributions of small pelagic fish resources such as anchovy (Lecomte et al, 2004). One of the climate phenomena that impacts fish resources is the El Niño Southern Oscillation (ENSO), which is a coupled atmosphere-ocean variability in the tropical Pacific Ocean. We proposed a hypothesis that a climate-driven temperature rise will result in the northward shift of anchovy habitat and increase of anchovy relative abundance We tested this hypothesis using the climate projections from the IPCC (Intergovernmental Panel on Climate Change)–RCP (Representative Concentration Pathway) scenarios. By the end of the 21st century (2081–2100), the IPCC-RCP scenarios projected that the global surface temperature would rise between 1.0◦C and 3.7◦C compared to the 1986–2005 baseline (IPCC, 2014b) This raises the urgent need to study the impacts of future climate change on fisheries. Using the Japanese anchovy as a model species to study this topic is likely to disclose processes and mechanisms similar to other small pelagic fisheries across the globe

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