Upwelling Impact on Sardinella lemuru during the Indian Ocean Dipole in the Bali Strait, Indonesia

Daduk Setyohadi,Adi Wijaya,Umi Zakiyah,Abu Bakar Sambah

doi:10.3390/fishes6010008

Daduk Setyohadi, Adi Wijaya + Show 2 more

Open Access

https://doi.org/10.3390/fishes6010008

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Abstract

Understanding the impact of Indian Ocean Dipole (IOD) on fishery around Indonesia is important as the fishery resources are small compared to the demand. In this study, we analyzed the effect of positive and negative phases of IOD on chlorophyll-a concentration and the catch of Sardinella lemuru in the Bali Strait. Data are based on field surveys in the Bali Strait during the positive and negative phase of IOD and Sea Surface Temperature (SST) and Sea Surface Chlorophyll (SSC) obtained from the analysis of satellite images. The results suggest that SSC concentration in the strait significantly correlates with the positive and negative phase of IOD, possibly through a change of upwelling and downwelling there. It is suggested that the change of phytoplankton biomass due to positive IOD would result in an increase of Sardinella lemuru in the Bali Strait. This research has direct implications as important information for the government in planning lemuru fisheries management in the Bali Strait based on oceanographic studies and climate phenomena.

Highlights

The Indian Ocean is the center of the occurrence of the Indian Ocean Dipole (IOD) phenomenon [1,2,3]
The waters of the Bali Strait are indirectly affected by the IOD phenomenon, in which primary productivity fluctuations occur in the surface layer due to the upwelling process that occurs in the Indian Ocean [12,13,14,15,16]
This condition affects the variability of chlorophyll-a concentration and sea surface temperature and affects the production of Sardinella lemuru in the Bali Strait

Summary

Introduction

The Indian Ocean is the center of the occurrence of the Indian Ocean Dipole (IOD) phenomenon [1,2,3]. The waters of the Bali Strait are indirectly affected by the IOD phenomenon, in which primary productivity fluctuations occur in the surface layer due to the upwelling process that occurs in the Indian Ocean [12,13,14,15,16] This condition affects the dynamics of Sardinella lemuru caught in the Bali Strait. The IOD period has an impact on the intensity of the upwelling that occurs This condition affects the variability of chlorophyll-a concentration and sea surface temperature and affects the production of Sardinella lemuru in the Bali Strait. STmheorme osingtnhilfyiccaanttchthoafn SinartdhineeIlOlaDlemphuarsueo(v+e/‐r),2a0ltyheoaurgshisthshisowwansianlsFoigiunfrleu2e.ncDeudrbinygththeenIuOmDbe(+r )apnhdaisneteinns2it0y06o,f 2f0is1h1i,n2g0a1c2t,iv2i0t1y5,in20t1h7e, B2a0l1i8Satrnadit.20T1h9e, SaSvCeraagneomcaatlcihesotfenSdareddinteollainlcermeausreu, lwanhdeeredasatSSthTe anomalies tended to be low This phenomenon can be used as an indicator of an increase in phytoplankton biomass which is followed by an increase in the production of Sardinella lemuru. During the period of IOD (−) in 2010, 2013 and 2016, the phytoplankton biomass was lower than usual and was followed by a decrease in Sardinella lemuru production (see Figure 2)

Comparison of Sardinella lemuru Catch with the IOD Phase

Materials and Methods