Effects of climate variability and climate change on the fishing conditions for grey mullet (Mugil cephalus L.) in the Taiwan Strait

Kuo-Wei Lan,Ming-An Lee,Pei-Yuan Wang,Long-Jing Wu,Kuo-Tien Lee,Chang Ik Zhang

doi:10.1007/s10584-014-1208-y

Kuo-Wei Lan, Ming-An Lee + Show 4 more

Open Access

https://doi.org/10.1007/s10584-014-1208-y

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Abstract

Grey mullet (Mugil cephalus L.) is one of the most important commercial species of fish in the coastal fisheries of Taiwan. In this study, we analyzed the long-term (1967–2009) records of grey mullet catch per unit effort (CPUE) in the Taiwan Strait (TS) to investigate the influences of climatic indices on the annual catch of grey mullet at multiple timescales. A wavelet analysis revealed that variations in climatic indices, namely the Pacific Decadal Oscillation (PDO), the Oceanic Niño Index, and sea surface temperatures (SSTs) might have affected the abundance and migration behavior of grey mullet in the TS in winter. The CPUE of grey mullet showed significant high correspondence with the annual PDO index (R 2 =0.82, p <0.01). The results suggested that the PDO affects the migration of grey mullet, but that increases in SSTs are a more important influence on the decreased catches of grey mullet after 1980. Mean SSTs increased 1.01 °C at the Chang-Yuen Rise in the TS from 1984 to 2009. The 20 °C isotherms in the TS in the winter also shifted from 23–24°N in 1958–1978 to north of 25°N after 1998. The fishing grounds of grey mullet also shifted to the north following changes in the 20 °C isotherm in the TS.

Highlights

The grey mullet (Mugil cephalus L.) is a cosmopolitan species that is distributed in tropical and temperate zones at latitudes 42°N–42°S (Thomson 1963)
The results of the regressions between climate indices and the catch per unit effort (CPUE) of grey mullet indicated that the annual CPUEs were positively and significantly correlated with the autumn Oceanic Niño Index (ONI), winter Pacific Decadal Oscillation (PDO), and annual PDO (Table 1)
The optimal model from stepwise multivariate regression analysis, including only the annual PDO, autumn ONI, and winter sea surface temperatures (SSTs) in the predictors, is expressed as follows: Log10(CPUE)=0.40*PDO +0.30*SST+0.18*ONI (R2=0.503, P

Summary

Introduction

The grey mullet (Mugil cephalus L.) is a cosmopolitan species that is distributed in tropical and temperate zones at latitudes 42°N–42°S (Thomson 1963). Previous studies have reported that the spawning and nursery grounds of the regional group of grey mullet affected by the NCCC are distributed in the coastal waters of the southeastern Taiwan Strait (TS). Tung (1981) discovered that the grey mullet lives in the coastal waters of China and that it matures at the age of 3–4 y. It migrates to the coastal waters of the southeastern TS for spawning in the cold NCCC in winter

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Discussion

Conclusion